Volume 1, Issue 2

Jo ur n a l o f FD R

June 2015 Volume 1 I ssue 2

Sc ien c e

Welcom e Welcome t o t he t hird issue of t he Journal of FDR Science. The aim of t his journal is t o share and showcase some of t he high qualit y st udent science t hat is occurring here at Colegio Roosevelt in L ima, Peru. I encourage you t o not e, as you read t hrough t he st udies in t his journal, t hat t hese st udies represent aut hent ic work t hat is original.

St udent s devised t heir own quest ion and creat ed experiment s t o at t empt t o answer t heir quest ions. Work found here was conduct ed wit hin our classes, for Personal Project as well as for Ext ended Essays.

Special t hanks must be given t o our st udent edit ors who are st art ing t o spearhead t he cont inued development of t his journal.

St udent Edit ors: - Savka Akest er (Grade 12) - Jae Hee K im (Grade 10) - Alejandra Vidal (Grade 10)

This t hird dit ion of t his journal would not be possible wit hout t he hard work of our t eachers and lab assist ant s who spend t ime and energy coaching and advising our st udent s. They help prepare mat erials, devise st rat egies and t each t he scient ific writ ing process. They inspire and provide opport unit ies for experient ial learning, discovery and inquiry. They edit and encourage st udent s t hrough t he cycle of improvement . Please join me in t hanking our Science depart ment t eachers and laborat ory assist ant s.

- Grade 6 & 7: Nikki Ellwood and Rae M arrigan - Grade 8 & 9: Rocio M alat est a and Amy Rebancos - Grade 10: K eit h Herold, L eigh Pet t y, Gilles Buck and Sam Bourke - I B Chemist ry: L eigh Pet t y - I B Biology: Davidand Gilles Buck - I B Physics: K eit h Herold - I B ESS: David Hoover and Allana Rumble - L aborat ory Assist ant s: Pat i M orit ani and Tabat a M olina Please join me in recognizing t he effort s of our st udent s whose work is showcased in t his journal. They produced high qualit y work for t heir st udies and t hen engaged in t he cycle of edit ing and review t hat is necessary t o have t heir work published. I would like t o t hank t hem for t heir effort and perseverance. Great job and congrat ulat ions.

A Colegio F.D. Roosevelt Science Depart ment Publicat ion Gilles Buck Edit or- I n- Chief Subject Area L eader Sciences I B Biology M Y P Grade 10

June 2015

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COVER PHOTO An onion (Allium cepa) root t ip preparat ion by 11t h Grade st udent St eve L iu. The root t ip was t reat ed wit h 1M HCl and st ained wit h met hionine blue. The root t ip was carefully t eased apart using a razor blade. The image was capt ured t hrough a light microscope at 400X magnificat ion using an iPhone camera. I mage t aken by 11t h Grade st udent Oscar Cart agena.

The essay below on det erminat ion capt ures t he grit necessary t o get such a prep and image.

Phot os in t he Jour nal All phot os feat ured in t he journal are t aken by t he st udent s or Get t y I mages

DETERMINATION

?Patience is bitter, but it?s fruit is sweet? ?Aristotle

by St eve L iu (Grade 11) ?I t ?s impossible?, I said as I peered t hrough t he small glass lens on t he microscope. I looked for t he small lit t le lines inside t he globular object s t hat float ed about in my field of view. Not hing. I t t urned out t hat finding t he process of mit ot ic division in an onion root t ip was harder t han Oscar, my part ner, and I t hought it would be. One hour passed, and as t he clock slowly t icked down I knew it was t ime t o brainst orm.

Then it st ruck me. As droves of people in my class began t o pack up t o go t o lunch or give up on t heir findings, I kept going. ?M aybe if I cut t he sect ion of t he root t ip t hat has t he highest percent age of cell replicat ion and isolat e it ... t hen just maybe.? I pondered about t his, and sprung int o act ion. I carefully cut a t hin slice off of t he t ip of t he root , and sliced it up, t hin enough for t he st ain t o show t he smallest of det ails below t he microscope. Eureka.

Science is not an easy subject . Beyond t he confusing numbers and puzzling t erms is t he process of t rial and error, t he process of eliminat ion, and ult imat ely, raw det erminat ion. Great scient ific discoveries did not come easy, and alt hough many of t hem accident al; it was t hanks t o t he pat ience of large t eams of scient ist s, or det ermined individuals who spent hours upon hours in t heir labs secluded from t he light of day.

I t t akes more t han being smart t o be a good scient ist . I don?t act ually consider myself compet ent in t he subject , but I do at t ribut e my pat ience and det erminat ion t o my success during t he experiment at ion process. I feel like it is a qualit y t hat a lot of young st udent s and scient ist s lack t hese days. The difference is in t he t ime and effort t hat you put in int o your work and learning from t he mist akes t hat you make along t he process.

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Tab le of Content s Daphnias Pg. 5

by Annika M ussell, Domenica L oor & Teresa De L a Vega

Shaped & Flavored Sugar Cryst als Pg. 9

by Et han Fairlie & Gabriel de Romaña Comparing t he Rat e at which Different Colored Tissues from t he Plant Codiaeum Variegat um Perform Phot osynt hesis Pg. 15

by Jimena Salinas The Effect of t he Concent rat ion of Ant ibiot ic on t he I nhibit ion of Bact erial Cell Growt h Pg. 23

by Romina L izier and Valent ina Alvarez The Effect of Sprinkler Type on Coverage Area Pg. 32

by Jose L uis Tejada, Juan L uis Quispe, The Effect iveness of Different Cleaning Agent s t o K ill Bact eria Pg. 40

by Ana L ucía Cabrera, Nerea Ramos and Alejandra Reynafarje Baking Wit h Solar Ovens Pg. 52

by Ariana Wu, Ariana L oor, Fernando Chero

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Dap hnias

by Annika Mussell, Domenica L oor & Teresa De L a Vega Grade 6

ABSTRACT We wanted to measure the effect of caffeine on the heart rate of daphnia (a small crustacean).

We did this by submerging daphnia into water with different amounts of caffeine, then we observed their heart rate under a microscope. I n the end we found out that the more caffeine a daphnia is exposed to the higher their heart rate will be.

BACKGROUND INFORMATION Daphnia is a genus of small freshwater plankton, usually called water fleas, found in ponds and lakes all over the world. T he top characteristic of the water fleas is that the main part of the body is enclosed in a shell, with the appearance of two lids, but made of one piece. By seeing the water fleas through the microscope, you can study their beating of the heart and follow the course of the blood round part of the body. T heir sizes are really different in general and have a weird way of reacting when at different temperatures. Since daphnias are see- through it is easy to find the heart as well as all their organs. Because of their minuscule size, substances have a much greater impact in their system. T hat is why we decided to use this crustacean to test Caffeine effect´s in their heartbeats. Caffeine is a stimulant of the nervous system, ?opposite? of alcohol that is a depressor.T his project will benefit the real world by informing the effects of coffee and other products with caffeine on the human body.

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QUESTION How does changing the amount of caffeine the daphnia is put in effect the daphnia's heart rate?

METHODS 1.

Dissolve 50mg of caffeine into 100

ml of water 2.

With your turkey baster take 1

daphnia and put it in the solution of 50 mg caffeine and 100 ml of water

HYPOTHESIS I t is predicted that the daphnia's heart rate will increase when it is put in water with greater amount of caffeine, also that that the daphnia's

3.

After 30 seconds use your turkey

baster to take it out and put it under the microscope 4.

Using a spoon, isolate it by taking all

the water away from it so it can't move 5.

Once it is immobile and focused on

heart rate will decrease when it is put

the screen, count its heartbeat for 15

in water with less amount of caffeine.

seconds.

We think this because we have all seen adults take these caffeine pills

6.

Repeat steps 1- 5 six times for 50mg,

25mg, 12.5mg and 0mg of caffeine

and they are using them to stay awake so they are used to accelerate heart rate and that is exactly what we are doing with the daphnia but it has a much greater effect on daphnias due to their size.

MATERIALS 100 mg pill of caffeine Wat er Tank full of living daphnias M icroscope

VARIABLES

5 cont ainers Comput er

Independent variable: T he amount of caffeine we put the water flea in.

Dependent variable: T he heart rate of water fleas after being in the substance for 30 seconds.

Control variables: Temperature of the substance, amount of liquid,

Turkey bast er Pet ri dish Scissors Paper Pencil L abels

amount of time daphnia is put in the substance.

6

RESULTS

trial 1

trail 2

trail 3

trail 4

trail 5

trail 6

Average

50.0

252

250

236

242

262

258

250

12.5

188

186

191

195

189

189

190

Heartbeats per minute

Amount of caffeine

Amount of coffeine

DISCUSSION Our Hypothesis was correct, as stated in

For instance, caffeine once consumed enters

our hypothesis that the daphnia's heart

your bloodstream from the stomach and small

rate will increase when it is put in water

intestine and begins to raise your central

with greater amount of caffeine or that the

nervous system activity levels giving you more

daphnia's heart rate will decrease when it

energy. T hat is why we predicted that the

is put in water with less amount of caffeine, we were able to prove it. We can now say this with confidence because there was more than a 60 heartbeat gap between the heartbeats of a daphnia exposed to 50 mg of caffeine and a daphnia?s regular 7

heart rate of a daphnia would react similarly as humans though thanks to their transparent and tiny it would be much easier to see the caffeine effect in their system. We noticed that in a lot of tests the daphnias were pregnant and just out of observation we came to the conclusion that most pregnant daphnias

REFERENCES "M icscape M icroscopy and M icroscope M agazine." M icscape M icroscopy and M icroscope M agazine. N.p., n.d. Web. 12 M ay 2015. ht t p://www.microscopy- uk.org.uk/mag/indexmag.ht ml? ht t p://www.microscopy- uk.org.uk/mag/art jun99/wflea.ht ml ht t p://www.arkive.org/wat er- fleas/daphnia- spp/image- A21531.ht ml ht t ps://bet adifferent iat ie.files.wordpress.com/2010/09/background- informat ion- on- daphnia. pdf

"Daphnia." Wikipedia. Wikimedia Foundat ion, n.d. Web. 12 M ay 2015. ht t p://en.wikipedia.org/wiki/Daphnia

"St udyZones.com | Act ivit y Zone St udyZones.com | Act ivit y Zone - An I nvest igat ion int o How Alcohol and Caffeine Affect t he Heart ."St udyZones.com | Act ivit y Zone St udyZones.com | Act ivit y Zone - An I nvest igat ion int o How Alcohol and Caffeine Affect t he Heart . N.p., n.d.

Web. 12 M ay 2015. ht t p://www.st udyzones.com/Act ivit yZone/Art iclePrint .cfm?Select edObjec t UUI D=97C846FB- F5D5- 11D4- B1C800B0D049C8DF

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had up to 2- 3 babies. We are sure we did our

way we got the water form the same place

experiment right because every time our data

before. We used the same type of caffeine

supported more our hypothesis and gave us

pills in all tests, and finally we took all the

accurate results. We are proudly allowed to

caffeine infected daphnias and we put them

officially say that the more caffeine a daphnia

in a separate water tank. We could have

consumes the faster its heart beat, we can now say this with confidence because there was more than a 60 heartbeat gap between the heartbeats of a daphnia exposed to 50 mg of caffeine and a daphnia´s regular heartbeat in plain water. T his project reflects on the thesis

collected different data for our dependent variable since it's about the heart rate of a general specie which could have impacted differently on another daphnia. With the data collected we are confident about our

that says that the more caffeine a person

answer and have accurate points of view that

consumes the greater amount of heartbeats

helped us reach a better understanding of

could end up crashing their system.

what the answer of this data meant. Within the process we faced a lot of problems that interfered in our experiment. T he most

T his scientific experiment was an incredible challenge but at the same time very usable experience for life. T hrough out the process we were able to realize a lot of things that are really impacting. We were able to control

heart and the materials functions. An example is how the heart of the daphnia was really tiny so we took a lot of time making a

mostly all the variables, in a few occurrences

efficient focus that leaded us to be able to

either the timing may have started some part

see its beats. Also the microscope we had, for

early or some time late. Also the daphnia's

it to work it needed to be installed as a

heart rate might have raised due to the fact

software and in the laptop different

that the daphnias probably were scared and the

programs had to be in there for all this to

process could have given them adrenalin. We

work. We had to use a blended laptop and

also must have took in some daphnias more

install the programs missing. All this

time to isolate a few of them (the more hipper

problems started as a give up chance and a

ones) so that part wasn't so accurate and

stress moment. We overcame all of this by

controlled. Sometimes the daphnias died in the

working as a team and supporting the

middle of the counting so it had a big impact

negative thoughts with good ones.

on the final data. We tried our best following the control variables we had listed above. We

made this control variables work by using always the same temperature of the water, we did this by using a thermometer and above that we never change dthe water for each steps, only if it was needed and in that 9

challenging problem was the view of the

Shaped & Flavored Sug ar Cr ystals

by Ethan Fairlie & Gabriel de RomaĂąa Grade 6

ABSTRACT

high ambient temperature causes

dissolved crystalline solid that

We wanted to figure out in

crystals to form faster than at a

than the liquid can hold. W hen

what temperature do sugar

low temperature because it

sugar is supersaturated in

crystals grow faster and

removes solvent from the solution,

water, nucleation will occur

bigger. We did this by

therefore forcing the crystals to

allowing sugar molecules to

boiling sugar, placing it in

form faster. L ow temperatures

stick together and form large

cups, placing it each

inhibit the evaporation of a

crystal structures. A substance,

environment (cold, hot and

solvent.

the solute, is dissolved into a

room temperature) and

T he molecules in crystals are

liquid, typically water. T his

observing it for 15 days. I n

different from the molecules in

liquid is known as the solvent,

the end we found out that

other substances because they are

and combining the two creates

the hot temperature made

aligned in a recognizable,

a solution. A specific kind of

the sugar crystals form

repetitive pattern. Since you can

solution is needed for crystals: a

bigger and faster.

dissolve more of a substance in

supersaturated solution. W hen

BACKGROUND INFORMATION

hot water than you can in cold

the solvent is heated, it is

water, a saturated state is

typically easier for the solute to

achieved by dissolving a substance

dissolve into it. A hot solution is

in hot water. As the solution

able to contain more solute

cools, it will hold less of the

than one that is cold. As the

dissolved substance. As it cools

heated solution cools, the

crystals will form. T hey will

solvent is unable to contain the

continue to grow for as long as

solutes, and they precipitate out

there is enough space and more of

of the solution as crystals.

the solute.

Changing the ambient

Crystals are solid materials that form when atoms or molecules form repeating patterns. Many ordinary substances can form crystals, such as salt or sugar.

Regardless of the material, all crystals are created in

temperature changes how

basically the same way: by

A saturated solution is one that

making a crystal solution. A

contains more molecules of a

quickly the solutes precipitate out of the solution.

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QUESTION

VARIABLES

W hat temperature creates

I ndependent Variable: t he

1.

Glass/plast ic cups

crystals faster and bigger in

environment t emperat ure

2.

W hit e sugar

Dependent Variable: Sugar

3.

Flavor you want t he

15 days (hot, cold or room temperature)?

HYPOTHESIS We t hink t hat cryst als will grow fast er in hot t emperat ure because heat makes wat er heavier and it also makes wat er evaporat e. Weight and evaporat ion will make cryst als grow bigger and fast er t han cryst als in cold or room t emperat ure. We t hink t his because wit h evaporat ion and heat , sugar will be all around t he cup wit h wat er (it will be easier and fast er for sugar t o get t o t he st ick).

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MATERIALS

cryst als growt h (more t han

cryst al t o be ( make sure

15 days)

all cryst als have t he same amount )

Cont rol Variable: boiled wat er t emperat ure, boiled t ime, amount of sugar and wat er per cup, what cup you are using, what st ick you are using, what t ype of sugar (whit e granulat ed sugar in a bag (big grained whit e sugar), t ime given for cryst al t o grow (15 days) and if t he glass cups used are clean or not .

4.

St icks (at least 10 cm

long, at least 0.5 cm wide) 5.

Thermomet er

(opt ional) 6.

Pot

7.

Food Coloring (use

same coloring for each cup on a t rial, as t he different chemicals t hey cont ain may alt er slight ly result ) 8.

Ruler

METHODS 1.

Add 3 cups of wat er in a pot dissolved it in

at t aching t he st ick t o some clips and t he clips

cold wat er and t hen boiled it , st irring t hem all

should be above t he cup, t hat way t he st ick

t he t ime,t hat way you're solut e will become a

will hang up.

sat urat ed solut ion.

2.

Add 1 t easpoon of t he flavor you want t he

cryst al t o be at t he solut e (sat urat ed solut ion) 3.

St op boiling when t he sugar get s

complet ely dissolved and t he sat urat ed solut ion is formed, boiled t he solut e for more t ime but not t oo much just unt il it become clear like honey.

4.

Aft er t hat split t he solut e (flavored

sat urat ed solut ion) in 3 different t ransparent plast ic cups.

5.

Then add t o t he sat urat ed solut ion 2 or 3

9.

Now you have t o put t he solut e on t op of

a lamp ( hot t emperat ure), because we already know t hat cryst als grow bigger in hot t emperat ure.

10. Aft er 3, 7 t ake out t he st icks and see if t hey grow more t han experiment 1 11. Aft er 7 days remove t he crust and t ransfer t he st icks t o new cups wit h t he remaining solut e and leaving t he cryst als t hat are at t ached t o t he sides of t he cups.

12. M easure t he cryst als wit h a ruler lengt h and widt h.

drops of t he food coloring color you want t he cryst al t o be. Add t his drops t o t he cup wit h t he solut e t hat is sat urat ed, hot , flavored, colored and in a cup.

6.

Then grab t he st icks (18 or more cm large

and wit h a widt h of 0.5 cm long or less) 7.

Dip t he st icks in t he solut e t hen dip t he

st ick in a cup t hat cont ains 1 cup of sugar.

L eave some sugar cryst als at t ached t o t he st ick. L et it dry for more t ime.

8.

Then put t he st ick inside 3 glass cups wit h

t he solut e( t he st ick should not t ouch t he sides or t he bot t om of t he glass (help yourself by 12

RESULTS

DISCUSSION Our Hypot hesis was kind of correct , cryst als grow more in hot t emperat ure t han in cold t emperat ure (it is kind of correct because part of t he answer t o our quest ion was NUCL EATI ON). The hot t emperat ure cryst al AVG was (L engt h 4 CM ) and (Widt h 6 CM ) in our first experiment but cont rolling t he variables of t he solut e t emperat ure and by let t ing t he st ick dry more in our t hird experiment we had an AVG of (L engt h 8 CM ) and (Widt h 2 CM ).

The answer t o our research quest ion is t hat cryst als grow bigger and fast er in hot t emperat ure because heat makes wat er weigh more and it also makes wat er evaporat e. Weight and evaporat ion will make cryst als grow fast er and bigger t han cryst als in cold and room t emperat ure.

I t is also very import ant t o cont rol variables like t he t ype of sugar ( more granulat ed sugar will make bet t er cryst als) t he t ime t he solut e is boiled ( boiling t he solut e unt il it t urned t ransparent is t he perfect t ime t o t urn t he heat off) , and finally t he t ime t he solut e is let t o cool down ( let t ing t he solut e cool down will not dissolve t he st ick wit h sugar) W hen sugar is supersat urat ed in wat er , t he molecules t ry t o escape, t hey can?t and nucleat ion happens. Nucleat ion is when sugar molecules st ick t oget her forming a large layer of molecules mixed t oget her (CRY STAL S) t hat at t ached t o a surface in our case t he st ick.

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We managed t o cont rol some variables like t he t ime we let t he sugar in t he st ick dry, t he t ime we boiled t he solut e and t he t ime we let t he solut e cold down before t ransfer it int o t he cups.

But we could not cont rol t he t ype of sugar we used in t he second experiment .

W hat we did t o cont rol t he independent variable was t hat we put t he t rial in room t emperat ure in a t able in t he middle of t he room but it is impossible t o cont rol t he same t emperat ure during t he day.

I n t he cold t rial we put it int o t he refrigerat or and t he t emperat ure inside never changed, and finally t he t rial in hot t emperat ure was always above a lamp and t he t emperat ure was more regular.

We collect ed enough dat a t o be

able t o answer our research quest ions because we made more t han one t rial. Our challenges were t o discovered when it was t he correct t ime t o remove t he solut e from t he heat , because if you let it for long t ime t he experiment can fail. We also discovered t hat is bet t er t o dissolve all t he sugar in cold wat er and t hen put in in t he st ove.

Our project was fun and also challenging. We made some mist ake t hat we t ried t o correct in t he ot her experiment s and we discovered t hat ...

We can learn science, we can eat science and we can sell science t oo! For more informat ion look our sit e: www.sugarcryst a.weebly.com

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REFERENCES Anne M arie Helmenst ine, Ph.D. 'How To M ake Homemade Rock Candy Or Sugar Cryst als'.

About .com Educat ion. N.p., 2015. Web. 22 Apr. 2015.

Educat ion.com,. 'Cryst al Wonderland | Educat ion.Com'. N.p., 2015. Web. 22 Apr. 2015.

Educat ion.com,. 'Growing Cryst als | Educat ion.Com'. N.p., 2015. Web. 22 Apr. 2015.

Educat ion.com,. 'Sixt h Grade Science Fair Project I deas | Educat ion.Com'. N.p., 2015. Web. 22 Apr. 2015.

Sciencebuddies.org,. 'Crazy Cryst al Creat ions: How To Grow The Best And The L argest Cryst als'.

N.p., 2015. Web. 22 Apr. 2015.

Sciencebuddies.org,. 'W hen Science I s Sweet : Growing Rock Candy Cryst als'. N.p., 2015. Web. 24 Apr. 2015.

Thehappyscient ist .com,. 'Text : Egg Geodes | The Happy Scient ist '. N.p., 2015. Web. 22 Apr. 2015.

Van.physics.illinois.edu,. 'Q & A: Sugar Cryst als - - Using Hot And Cold Wat er | Depart ment Of Physics | Universit y Of I llinois At Urbana- Champaign'. N.p., 2015. Web. 22 Apr. 2015.Wikipedia,.

'Rock Candy'. N.p., 2015. Web. 24 Apr. 2015.

15

Com p ar ing t he Rate at w hich Different Colored Tissues from t he Plant Codiaeum Variegatum Per for m Phot osynt hesis

by Jimena Salinas

INTRODUCTION Chlorophyll is an essent ial pigment for it is responsible of absorbing t he light t hat provides t he energy for phot osynt hesis. I t is found in chloroplast s, and it s molecules absorb blue and red wavelengt hs of light provided by t he sun. Since Chlorophyll molecules are unable t o absorb green wavelengt hs, green light is reflect ed causing plant s t o obt ain a green color. Wit hout chlorophyll, phot osynt hesis cannot happen; nevert heless, different colored plant s can also phot osynt hesize because chlorophyll can be present along wit h ot her pigment s, known as accessory pigment s.

Crot on or Codiaeum variegat um is a t ype of t ropical plant t hat is known for it s colorful leaves, which range from green, yellow, and black t o a combinat ion of all t hese. The different colors observed in it s leaves emerge due t o t he presence of different pigment s such as Chlorophyll, Carot ene and Ant hocyanin. (Janardan) W hen t he concent rat ion of Carot ene in a leaf exceeds t he concent rat ion of chlorophyll, t he plant adopt s a yellow color. This happens because Carot ene "absorbs blue- green and blue light in 16

sunlight " (Conrad). Hence since Carot ene cannot absorb yellow wavelengt hs, plant s cont aining t his pigment in abundance obt ain a

HYPOTHESIS

yellow or an orange color. Cont rary t o

The rat e of phot osynt hesis will vary among

Chlorophyll, Carot ene "cannot t ransfer energy

different colored t issues depending on t he

direct ly t o t he phot osynt het ic pat hway"

predominant pigment , associat ed wit h t he

(Boundless Biology); inst ead it t ransfers it s

color of t he leaf. I f 3 different colored t issues

energy t o Chlorophyll molecules t hat carry out

(red, yellow and green), from t he plant

phot osynt hesis.

Codiaeum variegat um, are t est ed under a

On t he ot her hand, red leaves on Crot on

whit e light desk lamp t hen, since a higher

shrubs obt ain it s color from a pigment called

concent rat ion of chlorophyll indicat es t hat

Ant hrocyanin. This t ype of pigment absorbs

t here is a great er amount of chloroplast s, t he

green and blue light . W hen it s concent rat ion

green colored t issues will phot osynt hesize or

exceeds t he concent rat ion of chlorophyll, t he

produce oxygen at a fast er rat e. Ergo, t he

plant obt ains a red or purple color. However,

rat e of phot osynt hesis for t he green colored

"[ Ant hrocyanin plays] no part in

t issue will be fast er t han t he rat e of

phot osynt hesis."(Conrad)

phot osynt hesis for t he red and yellow plant

This lab aims t o explore t he effect t hat t he predominance of different phot osynt het ic pigment s on leaves have on t he rat e of phot osynt hesis. This will be done indirect ly by t est ing t he rat e at which different colored t issues (red, yellow and green), from t he plant Codiaeum variegat um, perform t he process of phot osynt hesis measured by t he t ime it t akes for equally sized deoxygenat ed disks t o float t o t he surface of a beaker (100ml) cont aining H20 (100ml) and Sodium bicarbonat e (8 grams).

RESEARCH QUESTION

t issues.

The previous hypot hesis is based on t he not ion t hat chloroplast s are plast ids t hat carry out t he process of phot osynt hesis.

Since Chloroplast s cont ain chlorophyll, green colored t issues wit h a higher concent rat ion of chlorophyll should cont ain a great er amount of chloroplast s. Thus, a great er amount of chloroplast s should allow green t issue t o phot osynt hesize fast er t han red and yellow t issues, which exhibit a different color because t he concent rat ion of accessory pigment s, such as Carot inoids and

Do different colored plant t issues (red, yellow

Ant hocyanins, exceeds t he concent rat ion of

and green), from t he plant Codiaeum

chlorophyll. Since t he color of t he desk lamp

variegat um, phot osynt hesize at different rat es

is whit e, it combines all t he colors from t he

measured by t he t ime (Âą0.02 minut es) it t akes

spect rum; t hus t he color of t he lamp will not

for, equally sized, deoxygenat ed disks t o float t o

int erfere wit h t he result s.

t he surface of a beaker (100ml) cont aining H20 (100ml) and Sodium bicarbonat e (8 grams) under a whit e desk lamp?

17

METHOD AND MATERIALS 1.

Prior t o t he experiment , different colored leaves (green, yellow, and red) from t he plant

Codiaeum variegat um were collect ed and immersed in a 1000ml beaker wit h 250 ml of wat er.

2.

10 disks of different colored leaf t issue (green, yellow, and red) were cut for each t rial using a

paper puncher. This process was repeat ed 6 t imes for each of t he 3 t issue colors.

3.

Three 150ml beakers were labeled wit h t he one of t he t hree colors (green, yellow, red).

4.

100 ml of dist illed wat er were added t o each of t he beakers.

5.

Sodium bicarbonat e was weight ed using a weight scale (± 0.2 g). 8 grams of sodium bicarbonat e

were used per t rial.

6.

Sodium bicarbonat e was added t o t he beakers (150ml) using a spat ula t o t ransfer t he 8 grams of

powder (± 0.01 grams).

7.

The solut ion was mixed using a met al st irring rod.

8.

10 disks of t he same color were insert ed int o a 20 ml syringe and pushed int o t he bot t om wit h

t he plunger.

9.

The syringed was sit uat ed on t op of t he beaker and t he plunger was pulled out in order t o suck in

some of t he carbon dioxide wat er subst ance int o t he syringe cont aining disks.

10. The syringe was posit ioned vert ically (wit h t he adapt or on t op) and t he plunger was pushed t o eliminat e all t he air bubbles in t he subst ance.

11. Covering t he hole of t he adapt or wit h a t humb, t he plunger was pushed out and t he pushed up, in order t o remove t he air out of t he leaves. This allowed t he disks t o sink.

12. The liquid and t he plant disks inside t he syringe were t ransferred int o t he (150ml) beaker by pulling out t he bot t om of t he syringe.

13. Once t he plant disks had sink t o t he bot t om, a (11W ) desk lamp was put on t op of t he beaker. A met al st irring rod was used t o help t he disks sink.

14. A (250ml) beaker wit h (150ml) of wat er (used as a heat sink) was put on t op of t he (150ml) beaker cont aining t he disks.

15.

A chronomet er (±0.02 minut es) was used t o measure t he t ime it

t ook for t he first 4 plant disks t o float t o t he surface. St eps 8 t o 15 were repeat ed 6 t imes for each of t he 3 t issue colors.

16. Wat er was recycled and used in different t rials; however t he amount of wat er was maint ained by adding a lit t le bit of ext ra wat er whenever t he process of replacing t he disks caused t he wat er level t o go slight ly down. This prevent ed t he wast e of wat er. Disks were removed using a met al st irring rod.

17. Dat a was recorded in a dat a t able including t he t ime it t ook for t he first 4 disks t o float for each t issue color (green, yellow, and red).

18. An elect ronic t hermomet er was used t o cont rol t he t emperat ure.The work place was cleaned, and all mat erials used were washed.

18

RESULTS

QUALITATIVE DATA I t was observed t hat red leaves t ook t he longest t ime t o float t o t he surface of t he (150ml) beaker cont aining carbonat ed wat er. The fast est leaf disks t o float t o t he surface were t he green disks. I t was also observed t hat wit hout deoxygenat ing t he leaves by forming a vacuole wit h t he syringe, it was impossible t o sink t he disks t o t he bot t om of t he beaker before st art ing t he t est for t hey would st ay on t he surface of t he liquid. For t his reason, t aking t he air out of t he leaves wit h t he help a syringe was an essent ial st ep in t he procedure of t his

experiment . Phot osynt hesis was observed by looking at t he small bubbles t hat formed around t he leaf disks, t his was sign t hat t he plant s were producing oxygen. W hen enough bubbles were formed around t he disks, t hey would st art t o elevat e t owards t he surface of t he H20 (100ml) wit h sodium bicarbonat e (8 grams).

19

ANOVA TEST

Following t his result s, a one- way bet ween subject s ANOVA t est was conduct ed t o compare t he effect of different visibly predominat ing pigment s, green, yellow, and red, on t he rat e of phot osynt hesis of a single plant species, Codiaeum variegatum. There was a significant effect of color of leaf t issue on t he rat e of phot osynt hesis measured by t he t ime (Âą0.1 minut es) it t akes for leaf disks t o float t o t he surface of a beaker at t he p<.05 level for t he t hree condit ions [ F(2, 15) = 330.6103, p = - 0.0000] .

Because t he ANOVA t est indicat ed t hat t he result s were st at ist ically significant , a post hoc t est was comput ed. The Tukey post hoc t est , designed t o compare each of t he condit ions t o every ot her condit ion, indicat ed t hat t he mean score for t he green leaf disks (M = 2.48, SD = 0.83) differed from t hat of t he yellow (M = 3.79, SD = 0.79) and red (M = 6.59, SD = 1.23) leaf disks. However t here was a great er difference bet ween t he green leaf disks (M = 2.48, SD = 0.83) and t he red leaf disks (M = 6.59, SD = 1.23). Taken t oget her, t hese result s suggest t hat different visible pigment s wit hin a single species do have an effect on t he rat e of phot osynt hesis. Specifically, t he result s obt ained suggest t hat (under a whit e light ) green colored leaves phot osynt hesize fast er t han red and yellow leaves when insert ed under a whit e light lamp. I t should be not ed t hat light must be whit e in order for t his condit ion t o be t rue. Table 5 and Table 6 display t he result s of t he ANOVA t est conduct ed wit h t he help of t he one- way ANOVA calculat or from t he websit e of t he Depart ment of M at hemat ics and Physical Sciences from t he Sout hwest ern Advent ist Universit y. These result s are 20

* Graph 2. I llust rat es t he result s obt ained by conduct ing a one- way bet ween subject s ANOVA t est . By looking at t he dist ance t hat separat es t he rat e of phot osynt hesis of t he 3 different colors, it can be observed t hat t he result s were st at ist ically significant . Under a whit e light , green colored leaves phot osynt hesized fast er t han red and yellow leaves. This can be seen because t he green disks t ook less t ime t o float . The disks wit h a lower rat e of phot osynt hesis were t he red disks.

DISCUSSION The result s obt ained in t his lab support ed t he following hypot hesis: The rat e of phot osynt hesis will vary among different colored t issues depending on t he predominant pigment , associat ed wit h t he color of t he leaf. I f 3 different colored t issues (red, yellow and green), from t he plant Codiaeum variegat um, are t est ed under a whit e light desk lamp t hen, since a higher concent rat ion of chlorophyll indicat es t hat t here is a great er amount of chloroplast s, t he green colored t issues will phot osynt hesize or produce oxygen at a fast er rat e. Ergo, t he rat e of phot osynt hesis for t he green colored t issue will be fast er t han t he rat e of phot osynt hesis for t he red and yellow plant t issues.

The collect ed dat a concurs wit h t he hypot hesis because as predict ed, Graph 1 illust rat es a sit uat ion in which green disks t ook t he lowest period of t ime t o float t o t he surface of a liquid cont aining H20 (100ml) and sodium bicarbonat e (8 grams). Addit ionally, t he result s obt ained from t he one- way ANOVA t est conduct ed suggest t hat different visible pigment s in t he leaf t issues of t he plant Codiaeum variegat um do have an effect on t he rat e of phot osynt hesis.

Specifically, t he result s obt ained suggest t hat , under a whit e light desk lamp, green colored leaves phot osynt hesize fast er t han red and yellow leaves. As st at ed in t he just ificat ion, t his sit uat ion occurred because green colored t issues have a higher concent rat ion of chlorophyll, t hus t hey cont ain a great er amount of chloroplast s. Hence, a great er amount of chloroplast s allows green t issue t o phot osynt hesize fast er t han red and yellow t issues, which exhibit a different color because t he concent rat ion of accessory pigment s, such as Carot inoids and Ant hocyanins, exceeds 21

* Graph 1 shows t he average t ime (Âą0.02 minut es) it t ook for t he first 4 disks of each color t o float t o t he surface of a beaker (150ml) cont aining H20 (100ml) and sodium bicarbonat e (8 grams) over 6 t rials. I t can be observed t hat t he green disks t ook t he least t ime t o elevat e t o t he surface of t he carbonat ed liquid in t he beaker. This means t hat t he rat e of phot osynt hesis was great er for t he green disks t han for t he ot her disks. The increasing t rend in all t he colors is due t o t he progressive t imes, in which consecut ive disks elevat ed t o t he surface. The disks t hat t ook t he longest average t ime t o float were t he red disks; t his shows t hey had t he lowest rat e of phot osynt hesis.

t he concent rat ion of chlorophyll. However, it should be emphasized t hat light must be whit e in order for t his condit ion t o be t rue.

I n t erms of t he result s obt ained showing t hat yellow disks phot osynt hesize at a fast er rat e t han red disks, a possible explanat ion is t hat whereas Carot ene (responsible for t he yellow appearance of t he disks) is able t o t ransfer it s energy t o Chlorophyll molecules t hat carry out phot osynt hesis, Ant hrocyanin (responsible for t he red appearance of disks) does not t ake a role on phot osynt hesis.

Previous research has been done on t he effect t hat different colored light s and different plant species have on t he rat e of phot osynt hesis; however, lit t le research has been conduct ed on t he effect t hat different predominant pigment s, wit hin t he same species, have on t he rat e of phot osynt hesis.

Nevert heless, t he result s of a st udy carried out by Court ney M arne, Erin M arkley, and Travis Pecha from The Universit y of Colorado Boulder conform t o t his experiment as, aft er having performed a t - t est , it concludes in t hat ?green leaves did have a higher mean rat e of phot osynt hesis ? t han red leaves?. The result s in t his experiment are significant because t hey cont ribut e t o showing t hat 22

REFERENCES "Absorpt ion of L ight ." Boundless Biology. Boundless, 03 July 2014. Web. 07 Jan. 2015. <ht t ps://www.boundless.com/biology/t ext books/boundless- biology- t ext book/phot osynt hesis - 8/t he- light - dependent - react ions- of- phot osynt hesis- 81/absorpt ion- of- light - 375- 11601/>. " Conrad, Jim. "W hy Do L eavesChange Colors in t he Fall?" L eaf Color. N.p., n.d. Web. 07 Jan.

2015. <ht t p://www.backyardnat ure.net /lf_color.ht m>.

Janardan, K ausalya. "Akshay: Everywhere Science!!!" Web log post . Akshay: Everywhere Science!!! N.p., 23 Sept . 2013. Web. 07 Jan. 2015. <ht t p://kayjayr- akshay.blogspot .com/2013/09/everywhere- science.ht ml>.

One- way ANOVA Calculat or." One- way ANOVA Calculat or. Depart ment of M at hemat ics and

Physical Sciences from t he Sout hwest ern Advent ist Universit y, n.d. Web. 07 Jan.

2015. <ht t p://t urner.facult y.swau.edu/mat hemat ics/mat h241/mat erials/anova/>.

M arne, Court ney, Erin M arkley, and Travis Pecha. "L eaf Color and Phot osynt het ic Rat es."

The

Effect s of L eaf Color on Rat es of Phot osynt hesis. The Universit y of Colorado

Boulder, Fall 2014. Web. 07 Jan. 2015. <ht t p://www.colorado.edu/eeb/courses/1230jbasey/abst ract s/29.ht m>.

ACKNOW LEDGEMENTS A t hank you t o M r. Buck, who int roduced me t o t he M et hodology of work, and whose dynamic t eaching allowed me t o underst and t he concept s of Biology. I would also like t o t hank M s. Pat t y for her kind support and help in providing me wit h t he necessary lab mat erials.

23

The Effect of t he Concentrat ion of Ant ib iot ic on t he Inhib it ion of Bacter ial Cell Grow t h

by Romina L izier and

Valentina Alvarez

ABSTRACT We approached t he invest igat ion on t he effect of ampicillin concent rat ion on t he inhibit ion zone of bact erial growt h by alt ering t he

INTRODUCTION Research Quest ion: W hat is t he effect of t he concent rat ion of

concent rat ions of ampicillin in

ant ibiot ics wit h variat ions of 0.02mg/mL , 0.10 mg/mL , 0.18

five different variat ions,

mg/mL , 0.26 mg/mL and 0.34 mg/mL wit h an uncert aint y of ±0.5

insert ing t hem in agar plat es

mg/mL on t he inhibit ion zone of bact erial growt h measured by t he

wit h a E. Coli DH- 5 Alpha

diamet er of t he inhibit ion zone around t he ant ibiot ic discs placed in

bact erial cult ure t hrough filt er

t he bact erial agar plat es (in cent imet ers [ cm] wit h an uncert aint y

paper discs, and t hen measuring

of ±0.05cm) when t he t ype of bact eria (E Coli DH5 Alpha), t he t ype

t he inhibit ion zones around t he

of ant ibiot ic (ampicillin), t he t emperat ure inside t he incubat or

discs aft er 18 hours of

(37º, ± 0.05º), and t he composit ion of t he agar plat es are kept

incubat ion. The concent rat ion

const ant ?

of ant ibiot ic and t he size of t he inhibit ion zones, which indicat es t he growt h of bact eria, show a direct correlat ion and linear relat ionship bet ween bot h variables; we found t hat as t he concent rat ion of ant ibiot ic increases, t he inhibit ion zones also increases.

BACKGROUND RESEARCH Bact eria- single celled microbes (microorganism), wit h a cell st ruct ure cont aining no nucleus or membrane bound organelles. A single loop of DNA serves as t heir cont rol cent er where genet ic informat ion is st ored; some bact eria have a plasmid, which is an ext ra circle of genet ic mat erial t hat may cont ain genes t hat make t he bact erium resist ant t o cert ain ant ibiot ics. t he scient ific relat ionship bet ween bact eria and ant ibiot ic.

24

Ant ibiot ic- drug used t o t reat bact erial

Microbiology, 2015) T he region where no colonies

infect ions by causing t he cell wall t o

grow is wherever the concentration in the agar is

disint egrat e. They are chemicals t hat

greater than or equal to that effective concentration,

kill or inhibit t he growt h of bact eria,

called the zone of inhibition.

originally produced by one

Antibiotic concentration and bacteria- An

microorganism t hat select ively inhibit s

experiment conducted by the American

t he growt h of anot her.

Society for Microbiology says: Bacterial regrowth

Ampicillin- a semisynt het ic form of

occurred when the antibiotic concentration fell below

penicillin, used chiefly t o t reat infect ions

the minimum inhibitory concentration of the drug

of t he urinary and respirat ory t ract s. I t

against the strains tested? (Grasso, S).

is a bet a- lact am ant ibiot ic t hat at t acks Gram- posit ive and some Gram- negat ive bact eria. This happens because Ampicillin?s amino group allows it to penetrate the outer membrane of Gram- negative bacteria. Gram- negative bacteria- is resistant to multiple drugs and is becoming increasingly resistant to many ntibiotics (Center for Disease Control and Prevention).

E. Coli- Full name of Escherichia Coli is a Gram- negative, rod- shaped bacterium that normally lives in human and animal intestines. E. Coli DH5- Alpha is not a pathogen strain and was developed by D. Hanahan as a ?cloning strain with multiple mutations that enable high- efficiency transformations.? (Prof.

McDevitt, 2013).

Agar Diffusion Test and I nhibition Zone- Also known as the K irby- Bauer disk- diffusion method that ?measures the sensitivity of bacteria to antibiotics by culturing bacteria on solid growth media surrounding sources of drug.?(K irby- Bauer Disk Susceptibility Test, Boundless 25

METHODS AND MATERIALS * Put on gloves, goggles and coat s at t he beginning of each working day and use t hem for t he ent iret y of t he experiment .

Day 1: 1. The t ip of t he inoculat ing loop was heat ed in t he Bunsen burner.

2. One colony of E. Coli was picked wit h t he inoculat ing loop and placed in t he flask wit h 150 mL of L B Brot h.

3. The flask was left in t he incubat or overnight (18 hrs) for t he bact eria t o grow.

Day 2: 4. Table was wiped wit h 70% Et hanol and paper t owels.

5. The 6 125 mL beakers were st erilized.

6. 100mL of dist illed wat er were measured in t he graduat ed cylinder and poured int o one of t he six beakers. This st ep was repeat ed for t he six beakers.

7. The cont ent s of t he ampicillin pill were poured int o a measuring plat e. The following amount s were individually measured and separat ed: 2 mg, 10 mg, 18 mg, 26 mg and 34 mg (8mg int erval bet ween each).

8. The cont ent s of each measuring plat e were poured int o t heir corresponding beaker and t he ampicillin measure was st irred wit h t he wat er.

9. Using a hole puncher, 66 holes were cut on filt er paper and 12 discs were placed in each of t he beakers.

10. The t able was wiped wit h 70% Et hanol and paper t owels.

11. The flask of now- grown E. Coli DH5- Alpha colony was removed aft er 18 hours in t he incubat or.

12. Using a 100- 1000 micropipet t e, 100 ÂľL of E. Coli DH5- Alpha were t ransferred int o t he agar plat es, keeping t he lid of t he beaker as closed as possible for t he bact eria t o prevent ot her bact eria from cont aminat ing our t est subject s and t he bact eria were spread evenly on t he ent ire area of t he agar plat es.

13. The ant ibiot ic concent rat ion solut ions were set on t he t able paired accordingly t o t he agar plat es labeled for each of t he corresponding solut ions.

14. Using forceps, t he discs of filt er paper were picked up from t he ant ibiot ic solut ion and placed carefully on t heir corresponding agar plat e wit h bact eria. 5 discs were placed per agar plat e in a st ar format ion 15. Forceps were rinsed in dist illed wat er when we finished t reat ing wit h one concent rat ion and went on t o t he next .

16. St eps 17- 18 were repeat ed eleven t imes (unt il every bact eria populat ion has 5 filt er paper discs of it s corresponding concent rat ion of ant ibiot ic).

17. Agar plat es were sealed closed wit h Parafilm and st ored in t he incubat or at 37ÂşC 18. Table was disinfect ed wit h et hanol and paper t owels.

Day 3: 19. Table was wiped wit h et hanol and paper t owels.

26

20. Aft er about 18 hours, agar plat es were t aken out of t he incubat or 21. Agar plat e wit h 0.02mg/mL concent rat ion was set on t op of t he blue light illuminat or and, using a ruler, t he diamet er of t he inhibit ion zone around t he filt er paper discs was measured.

22. The agar plat es were wrapped wit h Parafilm and t he bact erial cult ures were discarded safely.

23. The t able was wiped wit h et hanol and paper t owels.

RESULTS

Qualitat ive Ob ser vat ions: ? All the inhibition zone diameters for the 0.34 mg/mL concentration trials were measured through radius. ? Agar plates contained condensed water in them when we introduced the bacteria. ? I n the 0 mg/mL concentration, a second bacterial culture grew in the agar plate due to unknown external factors (some possibilities could be: from our breath, from the air, etc.) (See Appendix A: I mage 6) 27

event ually kill t he bact eria, t hey st unt t heir growt h in t he beginning of t he process, wit h t he larger concent rat ions st unt ing t hem more t han lower concent rat ions (L awrence, Ant hony).

Anot her st udy by t he Public M edical Cent er, t oget her wit h US Nat ional L ibrary of M edicine and t he Nat ional I nst it ut es of Healt h st at ed t hat t he apparent generat ion rat e const ant for each E.Coli showed charact erist ic concent rat ion- dependent result s, which means t hat t he reproduct ion of E Coli was dependent upon t he concent rat ion of Trend st at ement : The graph shows a near perfect linear correlat ion, confirmed by t he coefficient of det erminat ion (R²

ant ibiot ic is was act ing against (K ohanski, Dwyer, Collins).

value), 0.99315. The error bars indicat e t hat t he dat a was most widespread in t he 26 mg/mL concent rat ion t rials, but t he

Our result s t urned out t he way t hey did

st andard deviat ions for t he ot her concent rat ion were

because ampicillin?s amino group allows

low/moderat e.

it t o penet rat e t he out er membrane of

DISCUSSION

Gram- negat ive bact eria and E. Coli is a Gram- negat ive bact erial. Once t he out er

Based on our research quest ion, we concluded t hat t here is a

membrane is penet rat ed, t he cell int erior

direct relat ionship bet ween t he increase of concent rat ion of

is exposed t o t he ant ibiot ic and t o ot her

ant ibiot ics and increase in t he inhibit ion zone of bact erial

hazardous compounds t hat not only kill

growt h. Based on t he fift y dat a point s, t he correlat ion bet ween

t he bact eria but also st op it from

one variable and t he ot her showed t o be nearly perfect , wit h a

reproducing (T, Nakae). This means t hat

coefficient of det erminat ion of ? 0.99. The init ial concent rat ion

a great er concent rat ion of ant ibiot ic,

of 0.02 mg/mL showed an average inhibit ion zone of 0.88 cm

because it is more powerful, will be

while t he highest concent rat ion of 0.34 mg/mL , showed an

quicker and more effect ive t o break t he

average inhibit ion zone of 2.69 cm. This comparison is t he most

out er membranes of t he cells t hat it

ext reme because it exemplifies wit h t he ranges of t he dat a, but

comes int o cont act wit h, killing a

t he concent rat ions t hat were closest t o each ot her st ill showed

great er surface area of bact eria in less

significant difference bet ween t he sizes of t he inhibit ions zones.

amount of t ime and t hus creat ing a

For inst ance, bet ween a concent rat ion of 0.10 mg/mL and 0.18

larger inhibit ion zone. L ower

mg/mL , t he average increment was of 0.42 cm.

concent rat ions will kill t he bact eria at a slower rat e and t hen make it easier for

Our conclusions are support ed by expert sources. A st udy by

t he bact erium t hat wasn?t in cont act

Nort h Carolina St at e Universit y t est ed and concluded t hat t he

wit h t he ant ibiot ic t o reproduce and

lag phase of E. Coli is most affect ed by t he varying

re- spread over t he surface area of t he

concent rat ions of ampicillin, which means t hat before ant ibiot ics

agar plat e quicker, t herefore yielding 28

smaller inhibit ion zones.

25%. I n t he dat a we collect ed, t he percent ual increase for t he average inhibit ion zone was always smaller t han t hat of

However, while our dat a demonst rat es correlat ion and causat ion, a conclusion support ed by professionals, it also demonst rat es a difference in percent ual proport ion bet ween t he increase in ant ibiot ic concent rat ion and

concent rat ion of ant ibiot ics, but t hey became more similar as t he concent rat ion increased. I n a real world cont ext , for example as relat ed t o dosage, it could be concluded t hat when concent rat ion is low, one would have t o increase it by a significant amount (considering t he measurement s we?re working wit h) t o get only a small change in t he effect on t he bact eria, but as concent rat ion increases, one would have t o alt er t he concent rat ion by less t o creat e t he same effect on t he bact eria.

t he diamet er of t he inhibit ion zone. The concent rat ions of

Alt hough t he correlat ion bet ween our variables was nearly perfect ly

ant ibiot ics have grown in a

linear, t he ranges exhibit ed in t he raw dat a demonst rat e t hat t here

much larger proport ion t han

was fluct uat ion among t he diamet ers of t he same concent rat ion.

t hose of t he diamet er. W hile

The difference bet ween t he averages and t he ranges varied bet ween

t he concent rat ion from 0.02

no less t han 10% or 0.10cm (in t erms of st andard deviat ion). For

mg/mL t o 0.10 mg/mL

example, t he average diamet er for t he 0.26 mg/mL concent rat ion

increases by 400%, t he average

was 2.16 cm, but t he act ual values ranged from 1.79 cm t o 2.81 cm,

inhibit ion zone diamet er for

showing a - 21% and +30% variance against t he average. The

0.02 mg/mL t o t he average of

st andard deviat ion was highest for t he 0.26 mg/mL concent rat ion,

0.10 mg/mL increases by only

at 0.32 cm (Âą 0.05cm). This uncert aint y is nat ural in any

61%. However, as t he concent rat ions increase, t he percent ual difference bet ween t he concent rat ions of ant ibiot ics and t he inhibit ion zone diamet ers get closer t o each ot her. W hen t he concent rat ion of ant ibiot ics increased from 0.02 mg/mL t o 0.10 mg/mL , t he percent ual increase was of 400% and t he corresponding percent ual increase in t he average inhibit ion zone was 61%, but when t he concent rat ion of ant ibiot ics increased from 0.26 mg/mL t o 0.34 mg/mL , t he percent ual increase was of 31% and t he corresponding percent ual increase in t he average inhibit ion zone was 29

30

EXTENSION OF EXPERIMENT An ext ension t o t his experiment t hat looks deeper int o t he relat ionship bet ween concent rat ion of ant ibiot ic and t he inhibit ion zone of bact eria growt h would be by manipulat ing variables such as t he amount of wat er (Ex: 50 mL inst ead of 100) wit h t he same amount s of ant ibiot ics (grams) and see t he difference in relat ionship once t he rat ios are uniformly modified. A furt her ext ension would be t o inquire deeper int o ant ibiot ic resist ance, alt hough in a very safe and cont rolled environment , t o know more about how resist ance can be avoided and ant ibiot ic modified t o at t ack resist ant bact eria.

31

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"Ampicillin." WebM D Drugs and M edicat ion. WebM D, n.d. Web. 11 June 2015. <ht t p://www.webmd.com/drugs/2/drug- 8613- 518/ampicillin- oral/ampicillin- oral/det ails>.

"Ant ibiot ic Use & Resist ance." Ant ibiot ic Awareness. N.p., 2012. Web. 11 June 2015. <ht t p://ant ibiot icawareness.ca/?page_id=14#01>.

"DH5- Alpha E.coli." M icrobeWiki. K enyon College, 14 Aug. 2015. Web. 11 June 2015. <ht t ps://microbewiki.kenyon.edu/index.php/DH5- Alpha_E.coli>.

"E. Coli (Escherichia Coli)." Cent er for Disease Cont rol and Prevent ion. U.S. Depart ment of Healt h & Human Services, 16 Apr. 2015. Web. 11 June 2015. <ht t p://www.cdc.gov/ecoli/general/index.ht ml>.

Grasso, S., et al. "New I n Vit ro M odel t o St udy t he Effect of Ant ibiot ic Concent rat ion and Rat e of Eliminat ion on Ant ibact erial Act ivit y."

Ant imicrobial Agent s and Chemot herapy 13.4 (1978): n. pag. Print . 1978 American Societ y for M icrobiology

"Growt h of Bact erial Cult ures." QI AGEN. QI AGEN 2013- 15, n.d. Web. 11 June 2015. <ht t ps://www.qiagen.com/us/resources/t echnologies/plasmid- resource- cent er/growt h%20of%20bact erial%20cult ures/>.

Hamilt on- M iller, J. M . T., and Saroj Shah. "Effect of ant ibiot ic concent rat ion on t he killing of St aphylococcus aureus and Ent erococcus faecalis: comparison of t he novel penem, M en 10700, wit h ot her ? - lact am ant ibiot ics." Oxford Journals- Journal of Ant imicrobial Chemot herapy (1999): 418- 20. Print .

K ohanski, M ichael A., Daniel J. Dwyer, and James J. Collins. "How ant ibiot ics kill bact eria: from t arget s t o net works." Nat ure Reviews M icrobiology (2010): n. pag. Print .

L awrence, K hadija, and M ichelle Ant hony. "The Effect s of Ampicillin on t he Growt h of Escherichia coli." Nort h Carolina St at e Universit y, Depart ment of M icrobiology Journal (2013): n. pag. Print .

Thonus, I . P., P. Font ijne, and M . F. M ichel. "Ampicillin suscept ibilit y and ampicillin- induced killing rat e of Escherichia coli."

Ant imicrobial Agent s and Chemot herapy (1982): 386- 90. Print .

T, Nakae. "Result Filt ers." Nat ional Cent er for Biot echnology I nformat ion. U.S. Nat ional L ibrary of M edicine, n.d. Web. 12 June 2015.

ACKNOW LEDGEMENTS We would like t o t hank M r. Buck and M r. Bourke for t heir const ant support t hroughout t he invest igat ion, and sharing t heir broad knowledge on t he t opic of bact eria.

32

The Effect of Sp r inkler Type on Coverag e Area

by Jose L uis Tejada, Juan L uis Quispe, and Marc Mirella

ABSTRACT W hat is t he effect of t he t ype of

INTRODUCTION There are several fact ors cont ribut ing t o t he coverage area of a

sprinkler nozzle wit h variat ions of

sprinkler. The main cont ribut ing fact ors are; pressure, nozzle

sled rot ary, 2- arm rot ary, st at ic

diamet er and flow rat e. The wat er pressure (Formally K nown

spray and mult iple st ream

as; Fluid pressure) is referring t o t he amount of collisions

(Variat ions Bet ween Spray and

part icles have wit h a surface which is measured as a force

Rot or Sprinklers) on t he effect of

exert ed upon t he surface. This means t hat if you increase t he

t he sprinkler coverage area

number of part icles of a cont ainer wit h a const ant size, t here

measured by t he radius of t he

will be a great er number of part icle collisions wit h a surface,

coverage area squared mult iplied

hence great er pressure. This would also mean t hat if t he

by ? (A=r2?) in cm +/- 0.5cm

part icles have a great er energy (Usually wit h t he increase of

when t he input wat er pressure,

t emperat ure) t here would be a great er amount of collisions

t emperat ure and out door

hence, increasing t he pressure of t he fluid. The diamet er of

condit ions are kept const ant ?

t he nozzle indicat es t he pat h t he fluid needs t o t ake in

Convent ional irrigat ion

order t o be dispersed by t he sprinkler.

sprinklers are very wast eful when it comes t o amount of wat er used.

We can observe in t he grassy areas around school are wat ered using said sprinklers. However, we want t o creat e wat er- efficient met hod t o wat er t he grass wit hout act ually using a drip syst em, given t he impract ical nat ure of t his syst em wit h regards on t he purposes and scales of t he school?s green areas.

By designing bet t er, more efficient wat er sprinklers, we can reduce t he school?s expenses and reduce t he wat er consumpt ion t he school uses whilst keeping our school areas and foot print green.

33

The apert ure has numerous effect s on aspect s such as t he; pressure, wat er t raject ory, and flow and applicat ion rat es.

However, when t he out put pressure of a sprinkler is kept const ant and t he apert ure is t he only aspect being changed, t he coverage area should increase as well. According t o t he equat ion; a=q/2.78ar (On which A is t he coverage area in hect ares, q is t he flow rat e in lpm, and ar is t he applicat ion rat e in millilit ers per hour) when t he flow rat e is increased - meaning t he amount of wat er flowing t hrough t he nozzle in a cert ain period of t ime- so does it coverage area as suggest ed by t he equat ion. L ogically t his makes sense if we t ake int o considerat ion t hat more wat er can cover a larger area if t he

pressures are kept

ult imat ely yield t he largest moment um which also plays a role in

proport ional t o a smaller body

t he coverage area of wat er.

of wat er. However, if we

There are t wo main classes of irrigat ion sprinklers; Spray

maint ain t he same input

sprinklers (W hich as it s name suggest s delivers a spray of wat er

pressure and deliver it

in mult iple or single direct ions) and Rot or Sprinklers (W hich

t hrough several different

usually are sprinklers who deliver a single st ream or somet imes

nozzles of smaller diamet ers

mult iple st reams of wat er which rot at e in circles). Usually, t he

t he result is t hat t he wat er

Rot or sprinklers have a large range since t he increase out put

t ravels fart her (W hich doesn?t

pressure is larger due t o t he single small nozzles which makes t he

int rinsically mean t hat it will

wat er have a larger kinet ic energy and hence t ravel longer.

cover a larger area) since

(Equat ion 2.) Spray sprinklers cover t he largest area since t hey

higher pressure means a

?spray? t he wat er across mult iple direct ions meaning t hat t he

larger kinet ic energy, which

same amount of wat er is displaced across a larger area, meaning

also means a larger

t hat it could have a lower applicat ion rat e meaning t hat it would

moment um meaning t hat it will t ravel a longer dist ance because it ?s current st at e will remain unchanged. However, larger range does not mean a larger coverage area.

According t o t he equat ion K = 1/2 * p* v2( I n which K is kinet ic energy, P is pressure and V is velocit y) a larger

M ult iple Spray

Two- Arm Rot ary

pressure will yield a larger kinet ic energy. Since a larger amount of kinet ic energy will also mean t hat t he wat er will t ravel a longer dist ance since it would have a larger moment um according t o t he equat ion P=2m* k (I n which P is M oment um, M is M ass and k is K inet ic Energy). As you may t ell from t he previous equat ion, t he t wo fact ors of mass and kinet ic energy of

St at ic Spray

Rotaty Sled Sprinkler

wat er relat e wit h each ot her and it is a balance in bet ween t hese t wo fact ors which will

34

RESEARCH QUESTION W hat is t he effect of t he t ype of sprinkler nozzle wit h variat ions of sled rot ary, 2- arm rot ary, st at ic spray and mult iple st ream (Variat ions Bet ween Spray and Rot or Sprinklers) on t he effect of t he sprinkler coverage area measured by t he radius of t he coverage area squared mult iplied by ?

(A=r2?) in cm (+/- 0.5cm) when t he input wat er pressure (+/- 5 kPa), t emperat ure (+/- 0.5? ) and out door wind condit ions (+/- 1 m/s) are kept const ant ?

HYPOTHESIS Coverage area is direct ly proport ional t o t he combinat ion of bot h t he flow rat e and out put wat er pressure. Due t o t he fact t hat t he coverage area is det ermined by t he equat ion a=q/2.78ar(On which A is t he coverage area in hect ares, q is t he flow rat e in lpm, and ar is t he applicat ion rat e in millilit ers per hour.).The equat ion above suggest s t hat when t he flow rat e of t he sprinkler is increased, so does it s area, when t he applicat ion rat e is kept const ant . Hence, t he flow rat e of t he sprinkler is posit ively proport ional t o it s coverage area. I n addit ion, t his sprinkler also makes t he wat er have a larger moment um since increased pressure allows for t he wat er?s kinet ic energy t o be larger according t o t he equat ionP=2m* k (I n which P is M oment um, M is M ass and k is K inet ic Energy)

JUSTIFICATION

SAFETY CONCERNS

I f t he sprinkler head select ed is t he 2- arm

The only safet y concerns t hat could apply

rot ary, t hen t he coverage area radius will be

would be wit h t he Cube 3D print er. M ake

larger hence covering a larger area, because t he

sure t hat when somet hing is print ing, you do

sprinkler will have a larger flow rat e since it

NOT t ouch t he hot plat e. This will result in

delivers t wice t he amount of wat er t han a single

1st or 2nd degree burns. M ake sure t here is

st ream sprinkler in a dispersed fashion and it

adult supervision. Be careful while handling

will also deliver t he wat er t hrough small nozzles,

mat erials t hat are made of glass. M ake sure

which will allow t he wat er t o have a larger

t hat no plast ic is left on green areas. Always

pressure and larger moment um.

pick up wast e plast ic and dispose of t hem appropriat ely.

35

MATERIALS AND METHODS 1. Download t he Sket chUp soft ware and creat e a new project .

2. Develop a common base from which each sprinkler will at t ach ont o and creat e one sled rot ary, 2- arm rot ary, st at ic spray, mult iple st ream and sprinkler gun.

3. Go on www.Cubify.com and download t he soft ware, once downloaded open

13. Connect t he T- connect ion wit h t he 500 kPa pressure gauge on one end t ube on one end of t he hose.

14. Connect t he sprinkler t o t he rubber hose.

15. Set t he M easuring t ape from t he cent er of t he sprinkler and unwind in a st raight line.

16. M easure t he t emperat ure and wind condit ions and asses if t hey fall bet ween t he ranges above.

cubify.

17.Turn on Wat er Source.

4. I mport Sket chup document in t he cubify soft ware and make sure your design

18. Adjust t he Faucet ?s handle so t hat t he wat er

is cent ered and finally click on t he build

pressure out put t ing t hrough t he nozzle is equal t o 345

but t on so t hat t he program can make t he

kPA by viewing on t he pressure gauge dial.

rest of t he changes before print ing.

5. Export file t o a ext ernal pendrive for t he print ing.

6. Plug in t he Cube 3D print er t o t he power cord and t urn t he Cube on.

7. Connect t he pen drive t o t he Cube 3D print er and select t he program and click PRI NT. 8 . Conduct t he Experiment on a large

19. M easure t he lengt h of t he sprinkler st ream by observing up t o where does t he wat er reach. Record in Dat a Table.

20. Turn off Wat er Source.

21. Repeat st eps 15- 19 five t imes wit h t he same sprinkler .

22. Repeat St eps 11- 120 wit h 2- arm rot ary, st at ic spray and mult iple st ream nozzles connect ed t o t he rubber hose.

out door area which is available for sprinkler use (Park,Soccer Field et c.)

9.Connect t he Pressure Gauge t o t he Sprinkler.

10. Place t he sled rot ary nozzle sprinkler in t he middle of t he area.

11. Connect t he rubber hose t o t he wat er source (Faucet ).

12. Cut t he hose about 3- 4 met ers from t he wat er source.

36

RESULTS TABLE

GRAPH

TREND STATEMENT Since we are comparing discret e and not ?cont inuous dat a values, t here is no correlat ion in bet ween t he x and t he y values t here is no correlat ion coefficient needed for t he represent at ion of t he dat a above. We may also not e t hat since t he measurement s were t aken in cent imet ers and our measuring t ool (I n t his case a met er st ick) did include millimet ers, we were able t o achieve a lower uncert aint y hence a ext remely low margin of error (Along wit h ot her fact ors t hat will be described in t he conclusion). This is why t he error bars are virt ually nonexist ent and seem a single bar, on our graph and because t he values are incredibly large in comparison t o t he 37

variat ion in t he result s of t he experiment .

DISCUSSION The hypot hesis we devised for t his research lab

M t =2m* (1/2* p* v2) ("Fluid Dynamics and

is: ? I f t he sprinkler head select ed is t he 2- Arm

Bernoulli's Equat ion.") which yields t he

Rot ary, t hen t he coverage area radius will be

moment um (M t ) given t he mass (M ), pressure (P)

larger hence covering a larger area, because t he

and velocit y (V) of t he moving fluid. Due t o t he

sprinkler will have a larger flow rat e since it

fact t hat t he t wo arm rot ary sprinkler makes t he

delivers t wice t he amount of wat er t han a single

wat er flow int o small nozzles, making t he

st ream sprinkler in a dispersed fashion and it

pressure significant ly increase. This in t erm

will also deliver t he wat er t hrough small nozzles,

makes t he wat er have a great er kinet ic energy

which will allow t he wat er t o have a larger

which when insert ed int o t he equat ion for

pressure and larger moment um.? M y hypot hesis

moment um above, yields a higher moment um.

in t his experiment was support ed because of t he

M oment um defines t he quant it y of mot ion, which

clear deduct ions t hat can be made upon t he

is complet ely relat ed t o how far an object will

result s on t he coverage area of each sprinkler

t ravel. Hence, t he higher t he pressure, t he longer

head. Once we t ried each sprinkler for five t rials,

t he dist ance t raveled. But as discussed earlier, t he

it was clear t hat t he 2- Arm Rot ary sprinkler had

dist ance t raveled by t he fluid doesn?t int rinsically

an ext remely large area and unquest ionably

mean t hat it will cover a larger area. Wit h t he

out performed t he ot her sprinklers in t erms of

equat ion: a=q/2.78ar(?I rrigat ion Efficiency."

coverage area. Aft er t he first t rial, t he 2- Arm

Howell) (On which A is t he coverage area in

Rot ary sprinkler had about t hree quart ers of t he

hect ares, q is t he flow rat e in lpm, and ar is t he

coverage area of t he nearest area coverage

applicat ion rat e in millilit ers per hour.) we can

sprinkler, which is t he sled rot ary wit h 266.7

det ermine t hat wit h a larger flow rat e and same

cm2. Aft erwards, it kept having consist ent

applicat ion rat e t here is a larger area. L ogically

result s varying from 402.40 t o 404.10 cm2

t his makes sense if we follow a example; if we have

across t he second, t hird, fourt h and fift h t rials,

a cert ain amount of wat er (Flow Rat e) in a

whereas t he ot her sprinklers?coverage area

cont ainer wit h a very large vert ical height

ranged from 67.5 t o 266.7 cm2. Addit ionally, on

(Applicat ion rat e) t his means t hat t he area has t o

average t he 2- Arm Rot ary had a coverage area

be small. However, if we have t hat same amount of

of 403.58 cm2 has a difference of exact ly 137.3

wat er in a cont ainer t hat has a small vert ical

cm2 from t he closest average coverage area. The

height t his would mean t hat t he cont ainer has a

clear verdict from t he dat a collect ed on our

larger base area, which is coverage area in t his

experiment undoubt edly verifies t he hypot hesis,

case. Since t he t wo arm sprinkler had t he same

t hat t he 2- Arm Rot or has t he largest coverage

flow rat e as t he ot her sprinklers (Since we never

area.

varied input pressure and used t he same source)

The scient ific principle behind t his set of

but t he amount of wat er t hat it delivered across

result s resides wit hin t he scient ific rules of

t he surface was low, t his would logically mean

pressure and coverage area propert ies. The

t hat t he sprinkler spread t he wat er across a

pressure plays a role on how far t he wat er t ravels

larger area. Scient ifically t he Two- Arm

according t o t he modified formula

Sprinkler excelled in bot h if t hese aspect s because 38

it included a small nozzle and had a small applicat ion rat e, which made it cover t he largest area.

T his lab had some control variables that could

instantaneous to provoke a measurable change.

Nonetheless, the action of measuring the radius of the watered circle could very significantly affect the results we collected. T his is because there will always be irregularities of the area

have been more persistent from trial to trial

covered by water, consequently creating an

during the conducting of the experiment. T he

irregular circle for us to measure. We

factor that accounted for the most uncertainty

approximated on what the average length of the

in between trial and trial was the outdoor

radius is and calculated the area of the wetted

conditions. T he outdoor conditions could have

circle left by the sprinkler. However, since we

significantly affected our experiment due to the

estimated the average radius for all of the trials,

fact that passing wind or even the variations in

this was more of a error in the measurement

temperature may have potentially created a

method rather than an uncontrollable variable.

difference in the results collected in between

Albeit, there were variables that were left

sprinkler trials. T he wind could have created a

uncontrolled in our experiment, the results

slightly oblong shape in the water pattern and

couldn?t have been more precise and accurate

hance giving the impression that the coverage

than the way we collected them. Although these

area was in fact more. Although the results had

would have been controlled in a scientific research

a significant difference in coverage area, had

laboratory, the uncontrollable variables remain

the wind changed randomly through trials

insignificant in comparison the the variance and

could have affected our results to a certain

scale that were required to ultimately change the

degree. Temperature plays a role in the

outcome of the experiment.

pressure of any fluid since it gives the particles a higher amount of energy, creating a increase in the number of collisions with a surface, leading ultimately to an increase in pressure (I n accordance with Charles's L aw of Gases). T he temperature was in fact an uncontrolled variable since we couldn?t regulate it at will, however, the variations necessary to create a significant pressure change in the water flowing through the hose are unrealistic. We minimized the effects of both temperature and wind by conducting the five trials per sprinkler immediately after finishing the previous trial, which made the variations virtually nonexistent since the trials were conducted in such a short timespan and the variations in these variables would have had to be enormous and 39

T his experiment allowed us to gain lots of insight on how the different types of sprinkler heads have an effect on the extent of water dispersion. I n general, this lab allowed me to see how simple everyday activities such as watering lawn can be explained and improved with the use of physics and scientific reasoning. A possible extension for this experiment is to explore the optimal pressure and flow rate required to cover the largest area with the same sprinkler. T he question I could draft from this is; ?W hat is the optimal pressure and flow rate required to cover the largest possible area??.

REFERENCES "Fluid mechanics." Britannica School. EncyclopĂŚdia Britannica, I nc., 2015. Web. 6 Apr. 2015. <http://school.eb.com/levels/high/article/110311>.

"I rrigation and drainage." Britannica School.EncyclopĂŚdia Britannica, I nc., 2015. Web. 6 Apr. 2015.<http://school.eb.com/levels/high/article/111031>.

"Annex I : I rrigation Efficiencies." Annex I : I rrigation Efficiencies. I rrigation Efficiencies, n.d. Web. 06 Apr. 2015.

"Selecting the Right Sprinkler Head." I rrigation T utorials. I rrigation T utorials, n.d. Web. 06 Apr. 2015.

"Fluid Dynamics and Bernoulli's Equation." Fluid Dynamics and Bernoulli's Equation (99): n. pag. Print.

Howell, Terry A. "I rrigation Efficiency." USDA 1 (200): 467- 72. Print.

Stryker, Jess. "How to Select the Best Rotor- T ype Sprinkler." How to Select the Best Rotor- T ype Sprinkler. Jess Stryker L iited, 2011. Web. 26 Apr. 2015.

3, L ecture. "OCW." T ypical Examples of L ow, Correct, and High Sprinkler Pressures (see Fig 5.5).

Pressure I s Too L ow Pressure I s OK Pressure I s Too High(n.d.): n. pag. OCW.USU. Utah State University. Web.

40

The Effect iveness of Different Cleaning Ag ent s t o Kill Bacter ia

by Ana L ucĂ­a Cabrera, Nerea Ramos and Alejandra Reynafarje

ABSTRACT

RESEARCH QUESTION

This experiment researched t he effect of using

W hat is t he effect of using different cleaning

different cleaning agent s (FDR Soap, Aval, Bat h

agent s (FDR soap, Aval, Bat h & Body Works,

& Body Works, Hand Sanit izer, and Dist illed

Hand Sanit izer, and Dist illed Wat er) in t he

Wat er) in t he zone of inhibit ion. The result s were

zone of inhibit ion when filt er papers wit h

measured by dipping t he filt er papers each in t he

cleaning agent are put in a pet ri dish filled

respect ive subst ances, put t ing it in a pet ri dish

wit h Escherichia Coli, measured in

filled wit h Escherichia Coli and measuring t he

millimet ers aft er being left for one day when

zone of inhibit ion (in millimet ers) aft er being left

t he amount of cleaning agent used (20 mL ),

for one day when t he amount of cleaning agent

size of pet ri dishes, filt er paper size (one hole

used, size of pet ri dishes, filt er paper size,

punch), t emperat ure (37 ° C), and incubat or

t emperat ure, and incubat or were kept const ant .

are kept const ant ?

Through t he dat a collect ed we concluded t hat FDR soap is t he most effect ive cleaning agent when killing bact eria.

41

INTRODUCTION Bact eria are oft en seen as ?germs?, or

applied on t he bact eria, it immobilizes t he cell

creat ures t hat are invisible t o t he human eye

membrane by st opping t he process t hat elongat es

and causes many of our sicknesses. However, not

t hese chains. (W hat M akes Ant ibact erial Soap

many know t he benefit s t hat it can also bring t o Ant ibact erial). Once t he process is st opped, t he us, since t hey coexist wit h us and all living

bact eria is not allowed t o grow any furt her. W hen

t hings all t he t ime. The creat ion of vit amins,

comparing t he effect of regular soaps t o

breaking down garbage, and maint aining our

ant ibact erial ones, t he t riclosan and similar agent s

at mosphere are a few t hings t hat are done wit h

make t he killing of bact eria more effect ive t han t he

t he help of bact eria (M icrobe World). And even

element s in a regular soap, which will ult imat ely

t hough t hey are microscopic single- celled

result in a great er zone of inhibit ion.

organisms, some bact eria are able t o resist t he

Cleaning agent s don?t always explain how

t emperat ure and physical condit ions t hat not

unnecessary domest ic use or excessive use could

even humans could resist t o. Now, of course not

pot ent ially make some bact eria resist ant t o all bact eria are beneficial for our body, t here are ant ibact erial subst ances. I t consist s of overuse of some t hat need t o be killed or removed, which is t hese product s t hat causes bact eria (as any ot her where cleaning product s come in hand.

Nowadays, media advert isement t end t o

living t hing would do) t o become more and more resist ant t o t he same ant ibact erial product being

press t he point t hat bact eria can be harmful t o

used wit h frequency (L aura BiM ugno). M oreover,

our bodies and must be eliminat ed by using a

t he int ended effect for an ant ibact erial subst ance

number of cleaning product s. I n t he

will no longer be enough t o kill bact eria, since a

compet it ion of product s on t he market ,

more powerful subst ance will be needed. Yet using

ant ibact erial cleaning product s t end t o assert

an agent even st ronger t han t riclosan can also have

t hat t hey kill 99.9% of t he bact eria. The

healt h and environment al implicat ions.

difference bet ween ant ibact erial and

To measure t he amount of bact eria being used it is

non- ant ibact erial cleaning product s are cert ain

necessary t o liquify it . This is done by put t ing a

agent s such as t riclosan t hat are found in t he

single colony of e.Coli in brot h and put t ing it in an

subst ance. This pot ent synt het ic chemical is

incubat or t o allow it t o grow here. The t emperat ure

ext remely effect ive in killing bact eria if used on

t he incubat or is at makes t he bact eria grow fast er.

low concent rat ions (I llumin). I n order t o

A micropipet t e can be used t o measure t he exact

underst and how t his st rong chemical is able t o

amount of bact eria t hat will be used. For t he liquid

kill bact eria (or disable t hem t o grow any

bact eria t o be spread equally and form a layer of

furt her), we must examine it s effect on a single

bact eria a spreader can be used. I n t his way

organism. Any cell of an organism cont ains a

bact eria can grow const ant ly around t he whole dish

cell membrane, which is put t oget her by t he

making t he result s reliable. The mat erial t hat

lipid bilayer, or ?fat t y?. They are long

makes t he filt er papers allow it t o absorb anyt hing,

hydrocarbon chains essent ial for t he cell

like an ant ibiot ic or a soap, and t hen form a zone of

membrane?s funct ion and growt h. W hen t he

inhibit ion if being effect ive. Agar will allow more

t riclosan or any ot her subst ance cont aining it is

bact eria t o grow and t he filt er papers wit h cleaning 42

agent (if t hey are effect ive) will

inhibition due to this. T he bigger the

form a zone of inhibit ion due t o

zone of inhibition, the more effective

t his. The bigger t he zone of

the substance is.

inhibit ion, t he more effect ive t he subst ance is.

Moreover, the intended effect for an antibacterial substance will no longer be enough to kill bacteria, since a more powerful substance will be needed. Yet using an agent even stronger than triclosan can also have health and environmental implications.

To measure the amount of bacteria being used it is necessary to liquify it. T his is done by putting a single colony of e.Coli in broth and putting it in an incubator to allow it to grow here.

T he temperature the incubator is at makes the bacteria grow faster.

A micropipette can be used to measure the exact amount of bacteria that will be used. For the liquid bacteria to be spread equally and form a layer of bacteria a spreader can be used.

I n this way bacteria can grow constantly around the whole dish making the results reliable. T he material that makes the filter papers allow it to absorb anything, like an antibiotic or a soap, and then form a zone of inhibition if being effective. Agar will allow more bacteria to grow and the filter papers with cleaning agent (if they are effective) will form a zone of 43

VARIABLES

of e.Coli in t he agar t o avoid killing a colony wit h t he heat .

W hen t he inoculat ing loop was cooled down, it was used at t hat immediat e moment t o scoop a single colony of e.Coli.

The 225 mL flask wit h brot h was slight ly opened and t he inoculat ing loop now wit h t he colony was dipped in it and st irred around. I t was immediat ely closed again using t he t in foil.

The flask was placed in t he incubat or at 37 ° C for 24 hours.

20 mL of each cleaning agent

METHOD & MATERIALS For t his experiment , prelim t rials were not conduct ed due t o lack of t ime. Since t he experiment consist ed in growing bact eria and using different subst ances t o see it s different

(Aval Soap, Bat h & Body Works, FDR, Hand Sanit izer, Dist illed Wat er) was poured int o five different 50 mL beakers.

effect on it , we did not know how much t ime it would t ake for

One of t he holes in t he t hree

t his t o occur. I t is not a procedure t hat can be done in a single

hole?s hole puncher was used t o

day, so making prelim t rials would t ake a very long t ime.

cut 10 filt er paper disks.

Also, when we began doing t he experiment , everyt hing was

The t weezers were used t o pick up

coming out as expect ed, t here weren't any inconveniences, so

t he disks from t he hole puncher

we were able t o use t his dat a as our final result s. Our

and put t hem in t he beaker wit h

procedure was previously consult ed wit h t he t eacher t o know

t he first cleaning agent .

which met hod and mat erials t o use for our specific research quest ion.

1. Brot h was poured int o a 225 mL flask.

2. The pet ri dish wit h agar and bact eria was slight ly opened,

The beaker was covered wit h t in foil t o close it .

St ep 12- 14 was repeat ed four more t imes wit h t he ot her cleaning agent s.

enough for t he inoculat ing loop t o ent er t o avoid ot her bact eria ent ering or leaving t he dish.

The inoculat ing loop was cooled down by t ouching a free spot

24 hours lat er: (For t he following 44

st eps, gloves were used)

one. This was done by picking one filt er paper disk at a t ime, slight ly opening t he

The 225 mL flask was removed from t he

pet ri dish and placing t he filt er paper disk.

incubat or (it looked cloudy because of t he

The lid was closed and paper film was used t o

bact eria t hat had grown over night ).

seal it complet ely.

10 pet ri dishes cont aining only agar were

St eps 24- 25 were repeat ed nine more t imes

gat hered.

wit h t he remaining pet ri dishes so t hat t here

All pet ri dishes were labeled according t o t he

were t en pet ri dishes wit h five filt er paper

cleaning agent it would cont ain and t he

disks each and t wo per cleaning agent .

number of t he pet ri dish (since t here were t wo

The dishes were st ored upside down in t he

pet ri dishes per cleaning agent ). For example

incubat or at a t emperat ure of 37 ° C and left

?Aval Soap 1?.

for 24 hours.

A pipet t e t ip was insert ed in t he t ip of t he 100- 1000 µL micropipet t e.

The 100- 1000 µL micropipet t e was used t o

24 hours lat er:

hold 100 µL of t he brot h wit h t he e.Coli. To be

The t en pet ri dishes were removed from t he

able t o do so, t he t in foil t hat was covering t he

incubat or.

225 mL flask wit h brot h and e.Coli was slight ly opened, enough so t hat t he pipet t e t ip

The first pet ri dish was put in t he luminat or.

could ent er and immediat ely closed aft er

The lengt h of t he zone of inhibit ion was

holding t he µL necessary.

measured for each filt er paper disk wit h a

The first pet ri dish was slight ly opened, and t he bact eria was insert ed in t he dish.

Wit h t he pet ri dish opened t he least possible,

ruler and recorded as raw dat a in a paper.

St eps 29- 30 were repeat ed wit h t he ot her nine pet ri dishes.

t he back part of a bent plast ic pipet t e was

Dat a was processed int o a dat a t able and t he

used t o carefully spread t he liquid all over t he

average and st andard deviat ion were

pet ri dish. W hen finished t he pet ri dish was

calculat ed.

closed.

St eps 20- 22 were repeat ed wit h t he remaining nine pet ri dishes.

Tweezers were used t o pick up five filt er paper disks of t he first beaker wit h t he first cleaning agent and were placed in t he pet ri dish one by 45

RESULTS

Qualitat ive Data: - I n one of t he pet ri dishes for FDR, one of t he filt er paper disks didn't st ick on t he agar like t he ot hers did so it fell down, since t he pet ri dishes have t o be st ored upside down for condensat ion. We couldn't use t his as one of our result s, t herefore it was recorded as an error. - I n t he t rials for AVAL , t he filt er papers had t oo much soap, so t here was a ring of soap around t he filt er paper, and around t hat ring, t here was anot her ring of inhibit ion.

- M ore bact eria grew around t he filt er paper disks wit h dist illed wat er since wat er had anot her t ype of unknown bact eria which when put t ing in t he agar wit h e.Coli allowed bot h of t hese t o keep growing t oget her.

- The zone of inhibit ion of some of t he filt er paper disks grew so much t hat t hey connect ed wit h each ot her.

46

DISCUSSION

47

I f filt er paper disks are dipped int o different

t he cont rol and least effect ive, did not kill any

cleaning agent s (Aval, Bat h & Body Works,

bact eria, having 0.0 mm average. Aft er FDR

FDR, Hand Sanit izer and Dist illed Wat er)

soap, t he second most effect ive cleaning agent

and placed in a pet ri dish filled wit h agar

is Aval, wit h an average of 5.0 mm. Very close

and spread e.Coli for 24 hours t o see t he

t o it is Bat h & Body Works wit h 4.0 mm of

lengt h in t he zone of inhibit ion, FDR soap is

average. Next , wit h a 2.6 mm difference, t he

t he most effect ive t o kill bact eria, according

hand sanit izer average lengt h of t he zone of

t o t he dat a. According t o t he dat a in Table

inhibit ion is 1.4 mm. Figure 1: Average

1: Bact eria K illed wit h Different Cleaning

Bact eria K illed wit h Different Types of

Agent s, t he average lengt h of t he zone of

Cleaning Agent s, shows clearly t hat FDR

inhibit ion, meaning t he amount of bact eria

soap is t he most effect ive in killing bact eria

killed by t he most effect ive soap, which is

since t he pink bar which represent s it is t he

FDR soap, is 9.4 mm while dist illed wat er,

most prominent by being almost seven t imes

bigger t han hand sanit izer and almost double t he size of Aval and Bat h & Body Works. We found out t hat t he soap t hat FDR uses is K imberly Clark, which is an ant ibact erial soap. The scient ific principle t hat is responsible for making t he FDR (K imberly) soap t he most effect ive in killing bact eria is an act ive ingredient in an ant ibact erial product , which is called Triclosan. This pot ent synt het ic chemical is ext remely effect ive in killing bact eria if used on low concent rat ions (I llumin) ot herwise it may lead t o bact erial resist ance. I n order t o underst and how t his st rong chemical is able t o kill bact eria (or disable t hem t o

DISTILLED WATER

grow any furt her), we must examine it s effect on a single organism. Any cell of an organism cont ains a cell membrane, and t hese are put t oget her by t he lipid bilayer, or ?fat t y?. They are long hydrocarbon chains essent ial for t he cell membrane?s funct ion and growt h. W hen t he t riclosan or any ot her subst ance cont aining it is applied on t he bact eria, it immobilizes t he cell membrane by st opping t he process t hat elongat es t hese chains. (W hat M akes Ant ibact erial Soap Ant ibact erial). Once t he process is st opped, t he bact eria is not allowed t o grow any furt her. To be able t o st op t his process, t riclosan inhibit s a bact erial enzyme, what makes a chemical react ion

AVAL SOAP

fast er. I n a react ion like t his, t he react ant is a subst rat e which fit s t oget her wit h t he act ive sit e of t he enzyme. W hen using soap, t riclosan t akes act ion by compet ing wit h t he 48

subst rat es as a molecule inhibit or t o st eal t he places of t he subst rat es. I t is a compet it ion bet ween bact eria and t riclosan t o arise in an act ive sit e. I t is when t riclosan wins t his bat t le by st ealing t he act ive sit e t hat it kills t he bact eria by st opping t he fat t y chain growt h (I llumin).

There is an int erference of t riclosan wit h t he gene t hat cont rols t he process of encoding t he enzyme. For E.coli it int erferes wit h a gene called Fabl. I t is st at ed t hat Triclosan acts as a competitive inhibitor when it binds to the active site of the ENR enzyme and forms a

HAND SANITIZER

FabI - NAD+- triclosan complex (I llumin).

L ike t his it forms a complex t hat was not part of t he process of t he cont rol gene which st at es t he success and effect iveness of t riclosan, since it is impeding t he synt hesis of fat t y acids, weakening t he cell membrane and in effect st opping bact eria from funct ioning correct ly. I n relat ion t o our experiment al lab, t he only subst ance t hat showed t o be ant ibact erial, and t herefore cont ained t riclosan, was t he K imberly (FDR) soap. This is why t he filt er papers covered wit h FDR soap were t he ones t hat result ed in a great er bact eria- free circle in t he Escherichia coli.

Accurat e and precise dat a was able t o be collect ed due t o t he procedure creat ed.

This one allowed us t o collect accurat e

BATH & BODY W ORKS

result s yet precision could have been bet t er. The way we chose t o collect our dat a was by using various cont rol variables measured wit h beakers, sizes, and shapes so t hat t he result s got t en

49

addressed t he specific variable we were measuring: t he amount of bact eria different cleaning agent s could kill. The same amount of cleaning agent used (20 mL ), t he size of t he filt er paper disks (one hole punch), t he t emperat ure (37 ° C), size of pet ri dish and incubat or were kept as cont rol variables t o obt ain t his.

For example, if t he size of t he filt er paper disks wouldn?t have been kept t he same, t hen t he filt er paper disk would have more soap which could have caused more e.Coli bact eria t o be killed. The amount of soap couldn?t have been measured and t herefore result s may have varied. This is why we could obt ain accurat e result s. As for precision, my procedure could

FDR SOAP

improve t o make my result s even more precise for example for FDR and Bat h & Body Works which have t he great est st andard deviat ions of 1.1. Alt hough t here are no out liers, it st ill could have been somewhat more precise so t hat t he st andard deviat ion would lower and t he error bars were smaller. Anyhow, we were able t o get t he accurat e result of which cleaning agent was more effect ive when killing bact eria. Below you can see errors, effect on t he dat a and improvement s t o our experiment which addresses t he accuracy and precision in our lab.

bact eria st art s growing on it again. Also, anot her idea for a lab could be t o see what organic mat erials kill bact eria, obt ain result s and compare t hese t o t he ones wit h soap already collect ed t o see what is more effect ive. Research we could do t o have a furt her underst anding of our t opic, could be t o see t he ext ent at which it is healt hy t o use a soap t hat kills a lot of bact eria, since bact eria is also healt hy for our skin. Our lab relat es t o t he out side world because people wash t heir hands daily wit h different soaps or ot her product s t hat disinfect wit hout knowing which is act ually best for t he healt h of t heir skin. Also, people are not aware

This experiment , could be ext ended t o do

t hat bact eria can be good t o some ext ent in our

more research about how you can kill and

hands, so t hey simply priorit ize t he opt ion of

prevent bact eria from growing. For

using ant ibact erial soaps.

example, an idea for a relat ed lab could be how much t ime each soap works unt il 50

51

REFERENCES

Angkadjaja, St ephanie. "W hat M akes Ant ibact erial Soap Ant ibact erial." I llumin. N.p., 1 Dec. 2007. Web. 13 Apr. 2015. <ht t ps://illumin.usc.edu/68/what - makes- ant ibact erial- soap- ant ibact erial/>.

"Ant ibact erial Cleaning Product s." Bet t er Healt h Channel. N.p., 24 M ar. 2015. Web. 20 Apr. 2015. <ht t p://www.bet t erhealt h.vic.gov.au/bhcv2/bhcart icles.nsf/pages/Ant ibact erial_cleaning_product s>.

"Bact eria." M icrobe World. N.p., n.d. Web. 13 Apr. 2015. <ht t p://www.microbeworld.org/t ypes- of- microbes/bact eria>.

DiM ugno, L aura. "Disinfect ant s: A Guide t o K illing Germs t he Right Way." M ot her Nat ure Net work. N.p., 21 M ar. 2013. Web. 12 Apr. 2015. <ht t p://www.mnn.com/healt h/healt hy- spaces/st ories/disinfect ant s- a- guide- t o- killing- germs- t he- right - way>.

M elone, L inda. "Does Ant ibact erial Soap Work Bet t er t han Regular Soap?" Everyday Healt h. N.p., 1 Apr. 2013. Web. 14 Apr. 2015. <ht t p://www.everydayhealt h.com/cold- and- flu/ant ibact erial- soap.aspx>.

52

Baking W it h Solar Ovens

by Ariana Wu, Ariana Loor, Fernando Chero

ABSTRACT Our object ive was t o find if it was possible t o bake food wit h a device t hat would replace modern day ovens t o help reduce t he consumpt ion of energy. Through research, we discovered t hat solar energy was a great subst it ut e, so we designed and built solar ovens out of cardboard boxes, aluminum foil, and st yrofoam. We carried out an experiment t o t est what angle should t he box?s flaps should be in t o bake fast er - in t his case we used cookies. Through t he course of 3 weeks we have been able t o build, modify, and perfect an oven t hat has given us successful result s. From all 5 different ovens, we were able t o conclude t hat t he oven wit h t he flaps at an angle of 90° was t he most efficient .

INTRODUCTION Using t he energy of t he sun is a green,

of fossil fuels emit t ed, result ing in having cleaner

inexpensive, and accessible way of baking food.

air (Natural Life).

Solar ovens aren?t exclusive for baking, but can

W hat one has t o consider in order t o build a

be used for cooking, heat ing, and obt aining clean

successful solar oven is: 1) how t hey can maximize

wat er as well. These are oft en int roduced t o

t he amount of sunlight reflect ed t o t he right

families of low resources t hat don?t have t he

direct ion, and 2) how t o maint ain t he heat obt ained

access t o regular ovens (Cooking With The Sun).

t hrough insulat ion. W hat is t he best way t o

Besides, t hese subst it ut es t heir wood ovens,

maximize t he amount of sunlight int o t he oven is

helping reduce deforest at ion; if t hey used one for

what we will be exploring by changing t he angle of

a year, it ?s est imat ed t hat t hey would save one t on

t he flaps of t he solar oven. The second t hing,

of firewood. Also, solar ovens lower t he amount s 53

insulat ion, can be accomplished by covering t he

heat s up enough t o conduct it s heat t o t he

ent ire oven so no heat escapes, and by creat ing

cookies, object which has a much cooler

t hick walls for t he oven and using mat erials such

t emperat ure t han t he heat sink. Finally, t he

as st yrofoam.

cookies are obt aining heat in t hree different

The principle behind solar ovens is t hat t hey are designed t o absorb more heat t han it releases. Since t he hole of t he box is being covered wit h a Vinifan layer, t his act s as a greenhouse roof, let t ing direct and reflect ed

ways, via conduct ion, convect ion, and t hermal radiat ion, as all t hree end up t ransferring heat t o t he main cool object in t he box, t he cookies (Hyper Physics).

We got t he idea of building a solar oven

solar rays go int o t he box, while ret aining all of

t hrough t he websit e Educat ion.com and

t he radiat ed heat inside t he box, inst ead of

t hrough a YouTube video where we got clear

let t ing escape as it normally would (Now You're

st eps on creat ing our first solar oven. Aft er

Cooking! Building a Simple Solar Oven).

concluding our preliminary t rials wit h t his oven,

Furt hermore, inside t he box t here is a st yrofoam

we came t o t he conclusion t hat we needed a new

piece paint ed black, which act s as a ?heat sink?,

oven design. Alt hough t he cookies did bake, it

because it absorbs direct and indirect sunlight

t ook t oo long and we designed a new oven

more significant ly t han t he rest of t he box,

t aking in considerat ion a bet t er insulat ion

reason for why t hat is t he part of t he box in

syst em and adding more flaps direct ing t he

which t he food is cooked. L at er on, t he

sunlight t owards t he cookies. So, we replaced

st yrofoam piece radiat es t he absorbed heat ,

t he pizza box for regular cardboard boxes,

which is t rapped inside t he box due t o t he

covering all four flaps wit h aluminum. We put

Vinifan and t he insulat ion mat erials used t o

on t he four sides inside t he box a t hick layer of

cover t he walls, heat ing t he box up and let t ing it

st yrofoam wrapped in aluminum, and in t he

reach higher t emperat ures (Now You're

bot t om a st yrofoam paint ed black. W hat we

Cooking! Building a Simple Solar Oven).

kept t he same was t he Vinifan layer t hat went

Convect ion, conduct ion and radiat ion of heat are also an import ant fact or in t he oven we

over t he hole of t he box just like in t he video.

Some safet y procedures we t ook were t o

have creat ed. Thermal radiat ion from t he sun, as

handle t he cookies and box wit h caut ion when

ment ioned before, is t rapped inside t he box and

reaching high t emperat ures, using rubber

is absorbed by t he heat sink inside t he box,

pot holders at all t imes. L ikewise, use t he ut ilit y

which t hen radiat es it back int o t he air inside

knife wit h caut ion when cut t ing t he st yrofoam

t he box. Convect ion t hen occurs when t he hot

pieces. Regarding environment al care, we made

air inside t he box st art s t o expand, becoming

sure t hat we left none of t he mat erials we used

less dense, and rising t o t he t op of t he box,

laying around in our t est place, especially since

making t he cooler air drop and get heat ed by

we had t o do t he t est ing out side.

t he radiat ion t he heat sink is emit t ing, event ually heat ing all of t he air inside t he box.

Conduct ion t hen t akes place when t he heat sink 54

RESEARCH QUESTION W hat is t he effect of having different angles of t he flaps on t he solar oven wit h variat ions of 70° , 90° , 110° , 130° , and 150° (+/- 0.5° ) on t he effect of how fast cookies are baked measured by minut es (+/- 0.5 minut es) when t he t ime of t he day, t he t emperat ure, t he size of t he oven, t he size of t he cookies (1 t ablespoon), t he brand of t he mat erials (Scot ch t ape, Aluminum foil: Reynolds W rap), t he brand of t he ingredient s (L aive but t er and ?Huevos de corral?), and t he brand of t he cookie mix (Bet t y Crocker) are kept const ant ?

MATERIALS & METHOD B. The ingredient s were mixed unt il all of

1. 5 solar ovens were made:

t hem were fully combined and t he cookie A. The inside of t he four flaps of t he

dough was made

cardboard boxes were covered wit h Reynolds wrap aluminum foil (figure 1)

3. Cookies were made t he size of a t able spoon and were flat t ened out

B. St yrofoam pieces t he size of t he int erior part of t he sides of t he box were cut (right , left , front , back, bot t om) C. All st yrofoam pieces except t he ones of t he bot t om were covered wit h a layer of aluminum foil (figure 2) D. The bot t om st yrofoam rect angles were paint ed black on t he t op (figure 3) E. All st yrofoam pieces were placed in t heir corresponding places (figure 4) f. A t hird of a sheet of paper was placed in t he bot t om (where t he cookies would be placed. For hygienic reasons) 2. The cookie mix was prepared

4. Two of t hem were placed on each box on t he paper on t op of t he black surface 5. Vinifan was used t o cover t he t ops of t he boxes 6. The flaps of each box were placed at different angles: 70° , 90° , 110° , 130° , 150° and a prot ract or was used t o measure t he angles 7. The init ial t emperat ure was measured and recorded inside each box 8. Each cookie was t imed for how long t hey t ook t o bake and t oot hpicks were used t o t est if t hey were done 9. W hen t he last cookie was done, t he final t emperat ure of all ovens were recorded

A. An egg and ½ cup of soft ened but t er were added t o t he Bet t y Crocker mix

10. We repeat ed t his procedure 4 more t imes in order t o have 5 t rials.

55

RESULTS

56

DISCUSSION Our research quest ion was: W hat is t he effect of having different angles of t he flaps on t he solar oven wit h variat ions of 70° , 90° , 110° , 130° , and 150° on t he effect of how fast cookies are baked when t he t ime of t he day, t he t emperat ure, t he size of t he oven, t he size of t he cookies, t he brand of t he mat erials, t he brand of t he ingredient s, and t he brand of t he cookie mix are kept const ant ?

From t he dat a collect ed from t he experiment , we can conclude t hat t he solar oven wit h t he flaps at 90° baked t he cookies in less t ime. W hat we did was bake cookies in 5 different solar ovens, each wit h t he flaps cont aining aluminum foil at different angles t o see what cookies baked fast er. As st at ed on t he dat a t able and graph above, t he amount of t ime t aken for t he cookies t o bake in t he 90° angle oven was an average of 42.4 minut es, while t he solar oven wit h t he flaps at a 70° angle t ook an average of 72.8 minut es; t he oven at 110° was a close second t aking 46.40; t he one at 130° t ook 53; and t he one at 150° t ook 91 minut es.

We can also not ice a correlat ion bet ween t he change in t emperat ure and t he t ime t he cookies t ook t o bake. The solar oven wit h t he flaps at 90° had t he highest change in t emperat ure, it increased by 48.2° celsius, and baked t he cookies fast er, while t he oven wit h t he lowest change in t emperat ure was wit h t he flaps at 150° only increased 31.2° celsius and baked t he cookies t he slowest .

The scient ific reasons behind why our solar ovens heat ed t he way t hey did was because of t he law of light reflect ion and because of t he insulat ion syst em in our ovens. Reflect ion involves t wo rays called t he incident ray and t he reflect ed ray. The incident ray is incoming ray, in t his case t he one coming direct ly from t he sun, while t he reflect ed ray like t he name says, is t he ray t hat is reflect ed from t he surface, in t his case t he aluminum foil. Bot h direct and indirect sunlight rays are lat er on t rapped inside t he box due t o t he greenhouse effect t he Vinifan causes. Once inside, t he radiat ion from t he sunlight is most ly absorbed by a piece of st yrofoam paint ed black which act s as a heat sink. This piece of st yrofoam absorbs t he majorit y of t he heat , and t hen radiat es it back int o t he oven, making it t he 57

perfect spot t o cook food.

emit t ing on t he bot t om of

and t he normal line form an

Due t o t his, t he Vinifan, and

t he box, event ually heat ing

angle, which is t he same

t he insulat ion syst em around

all of t he air inside t he box.

degree as t he one t he surface

t he walls, t he oven is capable

Conduct ion t ransfer of

will reflect as t he reflect ed

t o achieve high t emperat ure

energy happens when t he

ray but t o t he opposit e side.

levels, making it possible for

heat sink heat s up enough t o

(The L aw of Reflect ion) So,

us t o bake cookies wit h just

conduct it s heat t o t he

in t his case, t he reflect ed

t he energy of t he sun.

cookies, object which is in

rays in t he oven wit h t he 90°

Besides t he law of light

cont act wit h t he heat sink

flaps were bet t er direct ed

reflect ion and insulat ion,

and has a significant ly

t owards t he cookies. The

ot her responsible principles

cooler t emperat ure t han t he

oven wit h t he flaps at 110°

for our result s are

heat sink. I n conclusion, t he

managed t o heat up t he

convect ion, conduct ion and

cookies are obt aining heat in

second fast est since t he rays

t hermal radiat ion t ransfer.

t hree different ways, via

st ill reflect ed bet t er in t his

Thermal radiat ion from t he

conduct ion, convect ion, and

box t han on t he ot hers. This

sun rays is enclosed inside

t hermal radiat ion.

is also why t he oven at 150°

t he box and absorbed by t he

The reason why t he oven

t ook t he most t ime t o bake

heat sink inside t he box,

wit h t he flaps at 90° was

t he cookies since lit t le or no

which t hen radiat es t he heat

able t o heat up more t han

rays reflect ed t owards t he

back int o t he air inside t he

t he rest and bake t he cookies

inside of t he box; and, t he

box. Convect ion t hen t akes

fast er was because t he angle

reason why t he box wit h t he

place when t he hot air inside

t he light was reflect ed.

flaps at 70° t ook t he second

t he box st art s t o expand,

W here t he light hit s t he

longest even t hough it is

becoming less dense, and

surface, t here is an

close t o 90° , is because t he

rising t o t he t op of t he box,

imaginary line - t he ?normal

flaps are facing inwards, not

making t he cooler air drop

line?- perpendicular t o t he

allowing t he incident rays t o

and get heat ed by t he

surface. The incident ray

properly hit t he surface of

radiat ion t he heat sink is

t he flaps.

58

Now t hat we have creat ed a successful solar oven, we could begin t est ing it on ot her t ypes of foods and see what t he out come is. Aft er all, we are not creat ing any harm t o t he environment when conduct ing furt her t rials. We were wondering how we could carry out t his experiment and product t o creat e somet hing meaningful for ot hers. As we previously st at ed, we have a passion for helping ot hers and serving t he communit y; so we want ed t o know t o what ext ent can t hese ovens help people of low resources in Peru, whet her it ?s for cooking, baking, heat ing, or dist illat ion.

59

REFERENCES Hyper Physics. Georgia St at e Universit y, 2014. Web. Apr. 2015. <ht t p://hyperphysics.phy- ast r.gsu.edu/hbase/t hermo/heat ra.ht ml>.

Science Buddies St aff. "Now You're Cooking! Building a Simple Solar Oven." Science Buddies. Science Buddies, 30 July 2014. Web. Apr. 2015. <ht t p://www.sciencebuddies.org/science- fair- project s/project _ideas/Energy_p018.sht ml#summary>.

Spangler, St eve. Solar Oven S'more - Sick Science! #094. Sick Science! St eve Spangler, 26 June 2012. Web. 28 Apr. 2015. <ht t ps://www.yout ube.com/wat ch?v=xZJmz_t F4NU>.

Touchet t e, Bet h. "How t o M ake a Solar Oven." Educat ion.com. N.p., 2013. Web. Apr. 2015. <ht t p://www.educat ion.com/science- fair/art icle/design- solar- cooker/>.

"Hands- on Act ivit y: Cooking wit h t he Sun." Cooking wit h t he Sun. N.p., n.d. Web. Apr. 2015. <ht t ps://www.t eachengineering.org/view_act ivit y.php?url=collect ion%2Fcub_%2Fact ivit ies%2Fcub_energy2%2 Fcub_energy2_lesson09_act ivit y3.xml>.

"Cooking wit h t he sun: solar cookers are an inexpensive, green way t o cook out side." Nat ural L ife M ay 2012: n. pag. Print .

Curt is, Darwin O?Ryan, and L ouise M eyer. "SOL AR COOK I NG: RAY S OF TRANSFORM ATI ON." SOL AR COOK I NG: RAY S OF TRANSFORM ATI ON. Americas, Apr. 2005. Web. Apr. 2015. <ht t p://cedesol.org/docs/english/SolarCookingAmericas.pdf>.

"The L aw of Reflect ion." Physics Classroom. N.p., n.d. Web. 29 Apr. 2015.

ACKNOW LEDGEMENTS First of all, we would like t o begin by t hanking our parent s for t heir const ant support t hroughout t he weeks we carried out t his experiment . Wit hout t heir help, we would have st ruggled in t he logist ics of set t ing t his lab in mot ion, and in get t ing t he mat erials needed. Second of all, we would like t o t hank M r. Buck for lending us equipment , and fellow classmat es who assist ed wit h t he procedure (especially in t ast ing our cookies). L ast ly, we want t o give a special t hanks t o our t eacher, M r. Bourke, for lending us his classroom aft er school t o work on our solar ovens, and, because wit hout all of his help and const ant feedback, we wouldn?t have been able t o improve our experiment or develop a det ailed and t horough lab report . Thank you!

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Contact Coleg io FDR gbuck@amersol.edu.pe scienceatfdr.weebly.com 61

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