Volume 2, Issue 2

2016 / Volume 2 / Issue 2

Jo u r n al of FD R Sc ie n c e

WELCOME Welcome to this second issue of the Journal of FDR Science. The aim of this journal is to share and showcase some of the high quality student science that is occurring here at Colegio Roosevelt in Lima, Peru. I encourage you to note, as you read through the studies in this journal, that these studies represent authentic work that is original. Students devised their own question and created experiments to attempt to answer their questions. Work found here was conducted within our classes, for Personal Project as well as for Extended Essays.

Special thanks must be given to our student editors who are starting to spearhead the continued development of this journal.

Student Editors: - Savka Akester (Grade 12) - Jae Hee Kim (Grade 10) - Alessandra Vidal (Grade 10) Cover Photo and Table of Contents Source: -

Camila Bustamante (Grade 12)

This edition of this journal would not be possible without the hard work of our teachers and lab assistants who spend time and energy coaching and advising our students. They help prepare materials, devise strategies and teach the scientific writing process. They inspire and provide opportunities for experiential learning, discovery and inquiry. They edit and encourage students through the cycle of improvement. Please join me in thanking our Science department teachers and laboratory assistants.

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Grade 6 & 7: Nikki Ellwood and Rae Marrigan Grade 8 & 9: Rocio Malatesta and Amy Rebancos Grade 10: Keith Herold, Leigh Petty, Gilles Buck IB Chemistry: Leigh Petty IB Biology: David Hoover, Stuart Murray, Gilles Buck IB Physics: Keith Herold IB ESS: David Hoover and Allana Rumble Laboratory Assistants: Pati Moritani and Tabata Molina

Please join me in recognizing the efforts of our students whose work is showcased in this journal. They produced high quality work for their studies and then engaged in the cycle of editing and review that is necessary to have their work published. I would like to thank them for their effort and perseverance.

Great job and congratulations.

Carolina Sofia Gonzalez Editor-In-Chief Grade 12

TABLE OF CONTENTS Effect of egg type (store bought, organic & free rage) on CaCO3 concentration of eggshell...................................4 Investigating the effect of a salt's concentration on its specific heat capacity.....................................................10 The effect of temperature on the Vitamin C content of orange juice...................................................................17 Specific heat capacity of alcohols in an homologous series? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ..? ? 24 Investigating the Evolution to Multicellularity: The Effect of Centrifuge Speeds on the Cell Clumping of Yeast? ? ? ? ? ? ? ? ? ? ? ? ? ? ..? ? ? ? ? 29

EFFECT OF EGG TYPE (STORE BOUGHT, ORGANIC & FREE RAGE) ON CACO3 CONCENTRATION OF EGGSHELL

By Car men Heeren Int roduct ion

Abst ract This

investigation was designed to find the effect of egg type, store bought, organic and free range, on the calcium carbonate content of their eggshells. This was measured performing a back titration where the excess acid was neutralized using a base when the amount of eggshell (0.600 g ±0.001), amount of HCL (25 ml ±0.03), egg color (brown), amount of time in the oven(900 sec ±0.01) and temperature in the oven (110 C ±1) were kept constant. Organic eggs were found to have the lowest percentage of CaCO3 concentration while store bought eggs had the highest concentration of CaCO3 per sample.

Research Quest ion What is the effect of the egg type with variations of organic, free range and store bought eggs on the CaCO3 concentration of their eggshells measured by performing a back titration when the amount of eggshell (0.600 g ± 0.001), amount of HCL (25.00 ml ± 0.03), eggshell color (brown), oven temperature (110.0 oC ±1.0) and time in the oven (900.00 sec ±0.01 sec) are kept constant.

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To understand this lab one must first know about the three different variations of eggs being researched and their differences. The first egg type is the typical store bought eggs, which are said to be the worst eggs in terms of nutritional value. Basically the hens who lay these eggs are kept in small quarters or cages usually called battery cages where they are unable to exercise, they do not receive sunlight, have clipped beaks and wings to prevent harm and they usually eat commercial feed which usually contains grains such as ground-up corn and soybeans and antibiotics to avoid sickness (Wong). On the other hand organic eggs are said to be the best in nutritional content. The hens who lay these eggs are not kept in cages, hence have the ability to exercise, have some exposure to the sun, have clipped beaks and wings and eat grass, bugs and feed made from organic materials which is considered ?organic feed?.

These chickens are not treated with antibiotics, reducing exposure to pesticides(Wong). Finally the hens who lay free range eggs are mostly kept caged but are said to have some time outside of these cages, have some exposure to the sun, have clipped beaks and wings and eat a mixture commercial feed and organic feed (Wong).

Another important factor to know about is the impact of certain conditions the hens are kept under on the eggs calcium carbonate concentration. To begin with different breeds of hens will lay eggs with different calcium carbonate concentrations due to genetics, anyhow unlike common belief this is not the only determining factor.

The age of the hen and the stress levels it is kept under may impact the CaCO3 concentration since the older the hen or the more stress the less calcium carbonate it is able to produce. The nutrition of the hen is also a determining factor since hens with a commercial feed diet are found to depose less CaCO3 onto their eggs.

This happens due to various reason but the primary one is the facto high levels of phosphorus in blood can inhibit calcium mobilization. Another main reason for nutrition of the hen being so influential is that hens who have higher vitamin D3 can absorb calcium easier meaning the can depose more of it. (Factor influencing shell quality.)

It is also important to note the significance of CaCO3 in eggshells. To begin with calcium carbonate is created when calcium ions react with carbonate ions in hard water, this creates limescale which is water with high mineral concentration ("Calcium Carbonate" [Page #1]). Eggs can have anywhere between 90-95% of CaCO3 in the eggshell and it?s main purpose of to protect the egg ("Eggshells ? A Bioavailable"). . Other substances found in eggshells include phosphoric acid and nitrogen. The CaCo3 presents itself in crystal form stabilized by protein matrix which is tissue in animal cells made up of a mixture of proteins and polysaccharides in sulphated molecules ("Eggshell" [Page #1]). Excess or deficiency of CaCo3 content in eggshells will affect shell quality negatively. Basically an average of 4 grams of calcium intake per day is required by a layer to maintain good shell quality since only 50 - 60% of dietary calcium is used in shell formation reason for which laying hens need more calcium than those who don't lay. Other than that it is important calcium movement starts during the last 15 hours of shell formation drawing from bone and diet of the hen. Having high calcium levels in the gut of the hen is important to ensure most of the calcium is taken from its diet and not its bones ("Factors influencing Shell Quality").

So why is calcium carbonate important in eggs? Poor eggshell quality can come at a huge cost for the producer. For example about 10% of common store bought eggs break before or during collection as well as during transportation. Since CaCO3 concentration is a determining factor in the hardness of the eggshell it becomes very important ("Maintaining Egg Shell Quality"). Another reason eggshells high in CaCO3 concentration may be a benefit is because they can be used in animal feed providing the calcium content necessary or even as fertilizers (Ednah). Other than that eggshells are being investigated as a cheap bone substitute, due to calcium content, which appears to be very promising. This research was conducted in in vitro and aimed to find if granulated eggshells had effects on primary bone osteoblast. Beneficial results were found since differentiated cells were able to be influenced positively (Wiesmann, Szuwart, and

Neunzhen). Hence CaCO3 concentration is not only important to ensure protection of the egg but may also be useful after the eggs is consumed.

Met hod After careful consideration the data collection methods were decided upon. To begin with the variations of the independent variable, egg type, were decided basically by the types of eggs available in the area. After going to three different supermarkets and a organic fare the three type of eggs found were organic, free range and store bought. Three trials per egg type were decided upon to aim for high accuracy and precision, the limited amount of time provided was also a key factor in the decision. These decisions were determined after an hour long preliminary trial period when a back titration was timed in order to find the amount of trials that could be performed in the time period provided.

The dehydration of the eggshells was done at the experimenters home due to time constraints.The preliminary trials also served to provide rough values of 100% CaCO3 concentrations as well as to ensure knowledge on how to perform a back titration.

The only apparent risk in this experiment and its data collection method is the fact there is direct contact with chemicals such as 1 molar HCL and 1 M NaOH which could be potentially dangerous if they came in contact with the experimenter's eyes or mouth. To minimize this risk the experimenter wore eye gear at all times and never avoided touching their face while conducting the experiment. Due to the fact the chemicals were dilute gloves were no necessary since 1M HCl and 1M NaOH are not harmful to skin.

Anyhow, the experimenter washed their hand thoroughly after conducting the experiment to remove all traces of the chemicals. Other than that all glassware such as the burette, pipette and flasks were handled with care in order to avoid potential accidents if they broke. Hence no major risk was faced in order to conduct this experiment.

No materials used were toxic or harmful to the environment. Since the NaOH and HCl were dilute they could be thrown out the drain when the experiment was finished. Anyhow the experimenter aimed to use only the exact amount of the chemicals necessary as to not be wasteful No live organism (chickens) were used in the experiment.

Part 1 1. The experiment was conducted at the experimenter home, all data was collected by the same researcher.

2. A store bought eggs was broken and both the yolk and the egg whites were removed, it was washed thoroughly using distilled water and the egg membrane was peeled off.

3. Step 2 was repeated with two more eggs, the eggs were kept separated.

4. Each eggshell was placed inside an evaporating basin and in the oven for 15 minutes, 900.00 sec (sec ±0.01) at 110.0 Co (Co ±1.0).

5. Evaporating basins were removed from oven and left to cool until comfortable to touch.

6. Each eggshell was store in a different container until time of use.

Figure 1: Experimental Set Up

Part 2 1. The experiment was conducted at colegio Franklin Delano Roosevelt, all data was collected by the same researcher.

2. The pipette was washed with 1M HCL and the burette was washed and filled with 1M NaOH. Three erlenmeyer flasks were washed with distilled water.

3. Using a pestle and mortar one of the eggshells was grind to ensure the mass of the egg did not change the CaCO3 concentration.

4. The eggshell was then weighed using a weigh boat and 0.600g (g. ±0.001) of it was collected and placed into an erlenmeyer flask 5. Using the pipette 25.00 ml (ml ±0.03)of 1 M HCL was added to the erlenmeyer flask, 2 drops of phenolphthalein were added as well, the content was mixed using a stirring rod to aid the reaction 6. Steps 8-11 were repeated with the other two eggshells resulting in three different mixtures 7. The excess acid in the first erlenmeyer flask was titrated (back titration) using the 1M NaOH from the burette. NaOH was added until a light pink color remained, value of titrated acid were recorded 8. Step 13 was repeated with the other two mixtures 9. Steps 1-14 were repeated using organic eggs and then free range eggs

Result s Processed Data Table

Graph

Trend statement: The highest amount of CaCO3 concentration can be seen in the store bought eggs, 62.50.% (Âą0.39) while the lowest amount can be observed in organic eggs, 16.67% (Âą0.39). The free range eggs lay in the middle with a 29.17% (Âą0.39) concentration of CaCO3 per sample. The absolute uncertainty was used to determine the error and hence be applied in the graph via error bars. Although this data may lead to valid conclusions it is important to point out that due to the high concentration of HCl, minimum charges, such as 0.5 ml, in the amount of NaOH used to titrate the excess acid, which could be attributed to a number of reasons including waiting too long to close the burette, had a massive impact on the calculations. This is clear when observing the absolute uncertainty.

Discussion When I started this experiment I wanted to deduce the CaCO3 content in eggs since the equations for the back titrations go as follow, the first being the reaction between the eggshell and the acid: CaCO3 +2HCl ?

H2CO3 + 2Cl - + 2 Ca+ and the second being the back titration: HCl +NaOH ? NaCl + H2O. Anyhow it is important to note that the main assumption of this lab is that all of the carbonate is calcium carbonate since as one can see the calcium is a spectator ion which means it does not carry on into the back titration. After extensive research it is clear most of the CO3 is CaCO. Moreover I did answer the research question finding store bought eggs had the highest percentage of CaCO3 per sample averaging at 62.50% while organic eggs had the lowest percentage of CaCO3 per sample averaging at 16.67%. This is most probably linked due to nutrition. As mentioned above hens who lay store bought eggs eat a commercial diet, hens who lay free range eggs eat a mixture of a commercial diet and organic diet and eggs whole organic eggs eat only organic feed. This leads one to believe that organic feed supplies less CaCO3 than the commercial feed. Percentage error could not be deduced since there is no pre-existing data for the CaCO3 concentration in eggshells of different hen breeds. Anyhow, I was able to find literature values for brown eggs which I have decided to compare with my store bought brown eggs since they are the closest match. After performing my experiment I found the store bought brown eggs contained an average of 62.50% of CaCO3 while the literature values I found indicates a 99.4% percentage of CaCO3 in their eggshells (Calcium Carbonate). This shows a clear difference between the values

obtained and the literature values found.

This can be attributed to the main assumption of the lab, being that all the CO3 present is CaCo3. This leads to the strengths and weaknesses of my investigation.

To begin with some of the strengths include performing various trials for each egg type, performing the calculations for all trials and obtaining the average from there instead of averaging the amount of NaOH used from the start and sufficient time to follow the procedure carefully. Anyhow there were also weaknesses, one of these was the fact the environment of the classroom could not be controlled. However the biggest weakness was using 1M HCl since this concentration was very high meaning a small variation in NaOH used such as 0.5ml could cause a huge difference in % of CaCO3 in the sample, which explains why the standard deviation is so high. Hence if I had to do this experiment again I would use 0.1M HCl instead of 1 M HCl since it would take more time to react but small difference in the amount of NaOH, which could arise from different experimenters or how the burette is viewed, would not cause a big difference in the calculations.

The main assumption this lab was based on was the fact that the CaCO3 in the eggshells would only react with the HCl during their reaction and then the titration. Hence incorrect values of CaCO3 could have been assumed to react with the HCl leading to incorrect values for the calculations.

Another problem I was faced with was the fact not all of the eggshells reacted with the HCl for the same amount of time due to time constraints not allowing me to make each mixture directly before the titration. This

means the eggshell may not have reacted fully with the HCl. As commonly seen in titrations determining precisely when the mixture has become neutral is quite difficult, resulting in another source of error. Finally the eggshells may have not dried equally due to uneven distribution of heat in the oven resulting in a change of water content in each.

Furthermore I believe this lab opens up many questions which could be answered in a lab setting.

For example if given the chance I would like to investigate further weather sun exposure has any effect on the CaCO3 concentration of the eggs. Due to time constraints only eggs lay during the summer were used for the experiment, anyhow it would be interesting to see the difference between the values obtained now and those obtained by the eggs laid during the winter. This could potentially show another reason for CaCO3 difference in eggshells being the environment. Other than that a full analysis of what is in each eggshell would also reveal the effects of environment and nutrition on these.

References "Calcium carbonate." UK Essays. N.p., 23 march 2015. Web. 9 Mar. 2016. <http://www.ukessays.com/essays/chemistry/calcium-carbonate.php>.

"Calcium Carbonate." Wikipedia. N.p.: n.p., n.d. Wikipedia. Web. 29 Feb. 2016. <https://en.wikipedia.org/wiki/Calcium_carbonate>.

Ednah, Karamagi. "The Importance of Egg Shells to a Farmer." Collecting and Exchange of Local Agricultural Content. N.p., 19 Sept. 2007. Web. 29 Feb. 2016. <https://celac.wordpress.com/2007/09/19/the-importance-of-egg-shells-to-a-farmer/>.

"Eggshell." Wikipedia. N.p.: n.p., n.d. Wikipedia. Web. 29 Feb. 2016. <https://en.wikipedia.org/wiki/Eggshell>.

"Eggshells ? A Bioavailable Source of Calcium." The Healthy Advocate. N.p., 6 1 2010. Web. 29 Feb. 2016. <http://thehealthyadvocate.com/2010/06/01/eggshells-a-bioavailable-source-of-calcium/>.

"Factors influencing Shell Quality." The Poultry Site. N.p., 1 Mar. 2008. Web. 29 Feb. 2016. <http://www.thepoultrysite.com/articles/1003/factors-influencing-shell-quality/>.

"Maintaining Egg Shell Quality." The Poultry Site. N.p., 14 Mar. 2008. Web. 29 Feb. 2016. <http://www.thepoultrysite.com/articles/979/maintaining-egg-shell-quality/>.

Wisemann, Szuwart, and Neunzhen. "Eggshells as natural calcium carbonate source in combination with hyaluronan as beneficial additives for bone graft materials, an in vitro study." PubMed.gov. N.p., 16 Apr. 2015. Web. 29 Feb. 2016. <http://www.ncbi.nlm.nih.gov/pubmed/25885793>.

Wong, Stephanie. "All About Eggs." Wake the Wolves. N.p., 7 Aug. 2014. Web. 29 Feb. 2016. <http://wakethewolves.com/how-to-shop-for-eggs-organic-cage-free-free-range-brown-vs-white/>.

INVESTIGATING THE EFFECT OF A SALT'S CONCENTRATION ON ITS SPECIFIC HEAT CAPACITY

By Patr ick Chang

Research Quest ion How will the concentration of two different ionic compounds in water affect the specific heat capacity of the water?

In the diagram below, water molecules are only forming one layer around the sodium and chloride ions, however in reality there are several more layers. These form what is called a hydration sphere.

Int roduct ion The relationship between the concentration of a salt in water, and the water?s specific heat capacity comes down to the molecular level. It is not about how much matter is present per volume, but how does the matter react. (Brennan, ?A Study of the Relationship between Heat Energy and Density?).

According to the late California Institute of Technology professor Fritz Zwicky, the water molecules are rearranged when a salt is introduced. Furthering the explanation for the Research Question: as a salt?s cations and ions are dissociated from each other they attract different parts of the polar water molecules. This creates a firm and high-pressure structure around the salt?s ions, which prevents movement in order to spread energy. This reduces the amount of free water molecules able to move and be heated and as a result decreases the specific heat capacity of the liquid as well. The higher the concentration of a salt, or density of the liquid, the lower its specific heat capacity becomes.

(Zwicky, ?Theory of the Specific Heat of Electrolytes?)

(?OpenStax CNX? and ?78 Steps Health Journal?)

Mathematically, the inverse relationship that I attempted to verify can be expressed by the following equations: Q=mc?T & D=mV . If the heat energy equation is rearranged for specific heat capacity c=Qm?T, and the density equation is rearranged for mass m=DV, we can substitute mass yielding: c=QDV?T. This proves that as density increases, specific heat capacity decreases because it is divided by it.

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Met hods Safety: This experiment did not cause harm to the environment. However, while performing the lab I had to be careful when using the microwave considering the high voltage involved and the presence of water. Moreover, all scientific equipment had to be handled with care, specially the analytical weight balance and the beakers, which are very fragile.

I first gathered all my materials and organized them in a practical position considering the frequency of their usage. I took the 250mL beaker and cleaned it thoroughly to remove any dirt. I had to be cautious to dry the beaker afterwards because I did not want any free floating ions from the tap water I used to rinse the beaker. Once it was dry, I filled the beaker with distilled water until the 200mL mark (I had to be careful of measuring at the meniscus).

Then I poured the contents of the beaker into one disposable cup and recorded its initial temperature and measured its mass (excluding the mass of the paper cup). I placed the cup in the microwave and heated it for 45 seconds.

Immediately upon the removal I placed the thermometer in the cup and recorded its peak ?final? temperature. While doing so I held the thermometer such that the probe would not touch the inner walls of the cup. I repeated this two more times (with a new cup every time) to achieve an average of three trials. After having calculated the average change of temperature and average mass, I calculated the heat energy of the microwave using the equation: Q=mc?T where ?c? was the textbook value for specific heat capacity of pure water (4.186 J/g°C).

the 250mL beaker. I filled the beaker with distilled water until the 200mL mark, stirred the contents, and transferred the contents to a new paper cup. I then repeated the heating and weighing process for pure water. This was done a total of three times to create an average and then, knowing the heat energy of a microwave for 45 seconds, I calculated the specific heat capacity of water with 0.500 grams of Sodium Chloride: c=Qm?T . This process was done identically for 1.000, 1.500, 2.000 and 2.500 grams of Sodium Chloride. One complication I had to overcome was dissolving the greater amounts of the salt; at the higher increments of the salt, it became harder to dissolve. This made me have to stir slightly longer, although it never truly dissolved completely. Upon completion I recorded the data and updated my data table. Finally, I repeated the whole process but with Potassium Chloride and started analyzing the data. Throughout the experiment, which was done over three class periods (75 minutes), I maintained the location constant to have the amount of ventilation controlled.

I measured 0.500 grams of Sodium Chloride using the analytical weight balance (and other apparatus necessary such as the weighing boat and the powder spatula) and placed the salt into

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Result s

* The Specific Heat Capacity of distilled water is the only value with 4 significant figures because it was taken from the textbook and assumed to be accurate

The scatterplot above shows a negative correlation between the amount of salt added and the substance?s specific heat capacity; this is true for both salts (NaCl in orange and KCl in green). The vertical error bars are the absolute uncertainty of the Specific Heat Capacity (blue corresponding to NaCl and red corresponding to KCl). Horizontal error bars are also included, however due to their tiny magnitude they do not appear in the graph. Noticeably the vertical error bars are significantly large, hence indicating that there were several inconsistencies when gathering data. This is also evident through the Linear Regression value; both lines have a value significantly far from 1 (the maximum). This indicates that the lines do not fall very closely on the points and therefore do not represent the relationship between specific heat capacity and amount of salt very well.

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Discussion My research question was: How will the concentration of two different ionic compounds in water affect the specific heat capacity of the water? In the process of investigating the concept, it became increasingly evident that the more salt in water, the greater the temperature changed. However, after mathematically evaluating the uncertainties of my measurements, I realized that I was not able to reliably prove the inverse relationship.

The two lines representative of the tests with Sodium Chloride and Potassium Chloride have a similar negative slope indicating an inverse relationship in both cases (as amount of salt increases, specific heat decreases). In the two data sets, the maximum specific heat is 4.186 J°C g when no salt is added, and the minimum specific heat capacities occurred at 4.02 J°C g with 2.000 grams of Sodium Chloride and at 3.97 J°C g with 1.000 gram of Potassium Chloride.

However, the data remains inconclusive because the ±0.11 J°C g error bars allow for both the water with 2.500 grams of Sodium Chloride and the water with 2.500 grams of Potassium Chloride to have the equal specific heat capacity as pure water. It is interesting that the minimum specific heat capacity did not occur at the greatest increment of the salts (2.500 grams); this is likely due to the salt not dissolving completely.

Furthermore, the linear regressions for the lines are not ideal to accurately judge the concept, with 0.67 for the Sodium Chlorine trendline and a 0.27 for the Potassium Chlorine trendline out of a maximum 1.00. This means the calculated correlation is a very weak one. This makes sense considering the absolute uncertainty of the specific heat capacity (vertical error bars) is significantly large. In fact, the error bars are big enough to where the other trendlines could be drawn with a slightly positive slope ? the results are not as reliable as expected. This goes to say that while the results correspond to trendlines

with negative slopes, the error bars are too large for the trendlines to accurately represent the actual relationship. Therefore, the results remain inconclusive and highlight that there is significant room for improvement.

It is undeniable, after all, that the addition of an ionic compound does affect the specific heat capacity of water. This is due to the fact that there are more disassociated ions in water forming hydration spheres as mentioned in the Background Research. However, it would require further and more accurate testing to properly determine how exactly does specific heat change with respect to amount of a salt.

Due to the fact that as the amount of salt increased, less got dissolved, it would be better if more water were used per sample (e.g. 1 liter) in order to have more increments of salt to measure.

That way there could be more data points to analyze and create a better trendline. Moreover, more trials per increment of salt would be better since it would reduce the amount of random error. Three trials per increment of salt were not bad, but were still not enough to compensate the average if there was an outlier. An example of this is when I had 0.500 grams of Sodium Chloride and two mass measurements out of the total three were about 203.500 grams while they should have been 200.500 grams. Knowing that 1 milliliter of water has a mass of 1 gram, I am aware of the inconsistencies when measuring volume; in many cases the mass inside the cups was several grams different from what it should have been. For example, Trial 3 of Water with 1.500 grams of Sodium Chloride had a mass of 205.856 where it should have been 201.500 grams. This indicates that more water was present than should have. Another observation made during the experiment was that Sodium Chloride had some dark dots in the mix and that it was stored in an old container. This means that the salt may have gotten hydrated over time with

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the air?s humidity and contaminated by dirt; potentially the measured amounts of salt were not purely salt.

Finally, better measuring instruments could also be used, in particular the thermometer and 250mL beaker; these two had major absolute uncertainties. The thermometer has a 20% (Âą0.2) uncertainty and the 250mL beaker has a 5% uncertainty (Âą12.5). For the future, the 250mL beaker shouldn?t be the default instrument to measure volume (a volumetric pipette would create more accurate measurements), and a more accurate thermometer (more decimal places with less absolute uncertainty) should be used.

Additionally, considering that a great portion of the errors come from measuring the microwave?s heat energy, different apparatuses to transmit heat could be investigated prior the actual experiment to determine the most consistent heat source. This is because I assumed that the microwave emitted equal heat for all trials and that every part inside was heated equally, whereas in reality this is not always the case.

Possible heat sources worth investigating include a water boiler, a Bunsen burner, and the insertion of a heated object such as a dishwasher.

Ext ensions

have a negative slope as the Background Research suggested it would have; given that ?c? and ?D? are inversely proportional in c=QDV?T . However, I would like to experiment with other substances to verify whether this scientific relationship holds true for every compound, not just ionic ones. For example, a covalent molecule such as sucrose (C12H22O11), or a non-polar molecule such as ethane (C2H6).

Initially testing several different compounds was the goal, but due to the time constraints of 10-hours I had to reduce the scope of my investigation to just ionic compounds. This, however, is not to say that testing these additional substances is not worthy of investigation.

References Brennan, Sean. "A Study of the Relationship between Heat Energy and Density."

CALIFORNIA STATE SCIENCE FAIR (2010): n. pag. Web. 2 Feb. 2016.

"Inorganic Compounds Essential to Human Functioning." OpenStax CNX. N.p., n.d. Web. 01 Feb. 2016.

"Ionic Bonds." 78 Steps Health Journal. N.p., n.d. Web. 03 Feb. 2016.

"Specific Heat - Boundless Open Textbook."

Boundless. N.p., n.d. Web. 03 Feb. 2016.

Zinck, Ernest. "How Does Salt Change the Specific Heat Capacity of Water?" Socratic.org.

N.p., n.d. Web. 02 Feb. 2016.

Zwicky, Fritz. "THEORY OF THE SPECIFIC HEAT OF ELECTROLYTES." Norman Bridge Laboratory of Physics, California Institute of Technology (n.d.): n. pag. Web. 01 Feb. 2016.

Even though the experiment was flawed due to several scientific errors, the overall trendline did 14

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THE EFFECTS OF TEM PERATURE ON THE KINEM ATIC VISCOSITY OF CRUDE OIL

By Nina M olina This paper investigates the relationship between the temperature of crude oil and its kinematic viscosity. The viscosity of the same oil sample was measured at different temperatures in order to identify a correlation. It was found that the viscosity is inversely proportional to the square of the temperature of oil.

Abst ract

Research Quest ion What is the effect of temperature on the kinematic viscosity of crude oil?

Int roduct ion

The recent drop in oil prices was one of the causes for Russia?s current economic crisis. Having a mother that works for an oil company, the effects of oil prices on international economies is a topic I am very familiar with. I find the impact this has had on Russia particularly interesting, because in spite of having some of the world?s largest petroleum reserves, they still do not seem to produce oil efficiently enough to keep its economy stable. It was only after I found out that the country?s most important reserves are located in western Siberia that I realized why it would be more expensive for them to produce oil than it is for most countries. Their oil fields are so cold they need large-scale heating systems for their pipes in order to be able to pump and transport petroleum. At very low temperatures, some crude oils become so viscous it is impossible for them to flow.

Viscosity is a physical characteristic used to measure a fluid?s resistance to flow. There are two different types of viscosity: dynamic and kinematic. Dynamic viscosity is a measurement of the internal resistance in a fluid ? a high viscosity means a greater force is required to move a set of its molecules with respect to neighbor molecules within the fluid ? and is measured in Pascal-seconds (Pa s)(Types of Viscosity). Kinematic viscosity, which will be investigated in this paper, is used to describe a substance?s flow under the influence of gravity.

This quality is often used to identify crude oil as well as several petrochemical fluids. This quantity can either be measured directly or calculated by dividing the dynamic viscosity by the density of a substance; it is measured in the SI unit squared meters per second (m2s).

Another common unit used to measure kinematic viscosity is Stokes (St), where one St equals 10-6m2s.

Although this experiment relies on physics to describe crude oil?s behavior under different temperatures, chemistry is used to analyse the cause of any correlation found from this investigation. Viscosity in any fluid is caused by its intermolecular forces. Substances with strong intermolecular forces are also highly viscous (Wen). Different types of crude oil have a range of kinematic viscosities because each sample is composed of slightly different compounds.

Crude oil samples are often described with their American Petroleum Institute (API) gravity, which is a measurement of a sample?s density compared to that of water. The oil used in this 15

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experiment has an API gravity of 23.5 at a temperature of 25ยบC. Oils with the same API gravity also tend to have similar compositions.

The API has determined the composition of some petroleum samples, out of which the most similar to the one analysed in this report was extracted from Prudhoe Bay, Alaska, and has an API gravity of 27.8 at 20ยบC. These compounds are likely to make up a large part of the crude oil used in this experiment.

The main intermolecular forces acting between compounds in petroleum are London dispersions, these are interactions between temporary induced dipoles in non-polar substances. Although these are the weakest kind of intermolecular forces, crude oil is mainly composed large molecules, including long chains of hydrocarbons. London dispersion forces are the strongest between such compounds because they have a larger surface area exposed to interact with adjacent molecules. This means petroleum still has very strong intermolecular forces, in spite of being a non-polar liquid, and a high viscosity as well.

(Wen) Temperature has a big impact on a fluid?s viscosity. An increase in a liquid?s temperature ? which can also be thought of as an increase in the molecules?average kinetic energy ? weakens the attraction between its molecules. The strength of temporary dipoles tends to decrease at higher temperatures, meaning the compounds within the liquid are less attracted to each other and can move more freely, causing the viscosity to decrease. For a liquid, the kinematic viscosity is inversely proportional to the square of the temperature. This relationship can be seen from the general trend displayed in Figure 1.

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THE EFFECT OF TEM PERATURE ON THE VITAM IN C CONTENT OF ORANGE JUICE Research Question: How does the temperature of a 25mL sample of fresh orange juice affect its content (in gdm-3) of vitamin C?

By I vana Rizo Patron I ntroduction: Orange juice is an essential component of a typical breakfast in Lima, Peru.

Oranges, also known by this scientific name citrus sinensis, is a citrus fruit that belongs to the Rutaceae family that is known for its various health benefits.

Apart from being rich in minerals as calcium and providing antioxidant and anti-inflammatory agents, oranges have a high content of Vitamin C, what they are mainly known for ("Orange fruit nutrition facts?).

Vitamin C, also known by its chemical name ascorbic acid or its molecular formula C6H8O6, is an essential component in the human diet. It is a compound related to glucose that is necessary to maintain bones and 17

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not very reaction, however, two iodine compounds can be synthesized to form the complex ion of triiodide: I 2 + I ? I 3-. The two compounds that can be used to form triiodide are potassium iodine and potassium iodate. Triiodide is a reactive anion that can now be used to oxidize Vitamin C to form dehydroascorbic acid (C6H6O6). The reaction that occurs is the following:

tissue connected. Moreover, it is considered an antioxidant agent that can be used to combat bacteria and infections.

Naturally, it is found in vegetables and citrus fruits, including oranges. Ascorbic acid is soluble in water, why humans cannot C6 H8 O6 + I3- + H2 O ? C6 H6 O6 + 3I- + 2H+ store it in their body. Similarly, Once the triiodide reacts with humans do not produce this the vitamin C in the titration, the vitamin. For this reason, it must orange juice will change color be obtained by eating foods (or blue-black, indicating the end supplements) that contain it point of the titration ("Vitamin C").

(Helmenstine). The half reaction To find the content of ascorbic acid, the sample will undergo a redox titration with a triiodide solution.

Iodine itself, is fairly insoluble, and hence

of the oxidation of ascorbic acid is shown below: C6 H8 O6 ? C6 H6 O6 + 2H+ + 2e-

The reactant, the ascorbic acid, is oxidized by the triiodide solution, resulting in a loss of two electrons. The combined oxidation state of the six carbons in the ascorbic acid is +4, while in the dehydroascorbic acid it is +6. This shows a loss of two electrons, which is why they appear in the product side of the reaction. Moreover, two H+ are added to product side to balance the number of hydrogen atoms, and to equal the charges of the reactants and the products.

-

250 mL graduated cylinder 50 mL graduated cylinder 1000 mL volumetric flask 250 mL volumetric flask Electronic scale Pot holder Sodium Thiosulfate

Method Step 1: Prepare Iodine Solution The first substance in the experiment that had to be prepared was the titrant.

1) Using the balance, 0.302g of KIO3 and 5.212g of KI were measured.

Finally, the concentration of the iodine solution is needed to find the Vitamin C content of each sample of orange juice.

Consequently, a standard solution of ascorbic acid with known concentration was prepared. As a result, by determining the number of moles, and the corresponding ratios according to the equation of the redox titration, the concentration of the iodine solution can be found.

Mat erial s & Met hod Adapted from Anne Helmenstine?s article in About.com -

30 mL of 3M sulfuric acid 4.00g of KI 0.500g of KIO3 0.350g of Vitamin C (ascorbic acid) 400 mL of orange juice Starch indicator Distilled water 25 mL graduated cylinder 125 mL Erlenmeyer flask Pipette Funnel Hot plate Thermometer 2 2, 50 mL beaker 50 mL burette and ring stand

2) In a labeled 1000 mL volumetric flask, add KI and KIO3 using a funnel to avoid spilling. Then 320mL of diluted water was added and mixed to dissolve the compounds. A problem was that some KI and KIO3 were stuck in the funnel.

Therefore, the water was added using the same funnel to add the missing residue.

Distilled water is used to avoid the chemicals in tap water.

3) This was added and mixed in 30 mL of 3M sulfuric acid and another 270 mL of distilled water to dilute the solution to a total of 600mL. Step 2: Prepare Vitamin C Standard Solution In order to find the concentration of the iodine solution, first a Vitamin C standard solution had to be made with ascorbic acid and water.

1) Using an electronic scale, measured 0.350 grams of ascorbic acid.

2) In a labeled 250 mL volumetric flask, the ascorbic acid was added and enough distilled water to mix the solution and dissolve the acid. Next, diluted the solution with distilled water to 250 mL.

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Step 3: Titrating the sample A 25 mL sample is titrated to find how much of the iodine solution is needed to reach the end point. Consequently, the Vitamin C content of each sample can be found.

1) Set up burette and ring stand. Filled burette with iodine solution, placing a 50mL beaker underneath burette in case some iodine solution spilled. Recorded initial iodine reading.

2) Using a 25 mL graduated cylinder, measure 25mL of the Vitamin C standard solution, poured into Erlenmayer flask and added 12 drops of starch indicator using a pipette.

sample was heated in a 50mL beaker using a hot plate. The temperature was monitored with a thermometer, and a potholder had to be used. A problem was that reaching and maintaining the desired temperature was impossible. To be as accurate as possible, as soon as the thermometer marked the desired temperature, rapidly, the sample to the Erlenmayer flask was transferred, and performed the titration. For data processing purposes, the temperature was assumed to have stayed constant.

Dat a Col l ect ion Table 3. Processed Data: Vitamin C content of Each Orange Juice Sample.

3) Flask was placed under burette and the sample was titrated, mixing until the sample turned blue-black, indicating the end point. A problem encountered was that measuring the same end point in each trial was impossible, since it was done by eye. Nonetheless, the same shade each time was tried to be achieve . Once end point was met? final reading of the iodine solution was recorded.

4) Solution was neutralized product with sodium thiosulfate, to reduce the environmental damage, and poured down the drain. It is safe to dispose when substance has turned clear.

5) Two trials were carried out for each sample.

6) The previous steps were repeated with each of the 25mL orange juice samples.

The orange juice was freshly squeezed with no pulp. First, the sample was at room temperature, then at 35°C, 45°C, 55°C, 65°C, 75°C and 85°C. Each orange juice

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Discussion The objective of this lab was to find how the temperature of a freshly squeezed orange juice sample affected its content of vitamin C (ascorbic acid). A 25 mL orange juice sample was measured at 25.3 °C, and thereafter in increments of 10°C. After performing the experiment, it was determined that temperature and Vitamin C content have an inverse relationship. As the temperature of the orange juice sample increased, the vitamin C content of the sample decreased. Firstly, at 25.3 °C, room temperature, the vitamin C content of the orange juice sample was 0.683g/ dm3 . Next, at 45 °C, the vitamin C content was 0.421 g/ dm3 . This 20 °C increase in temperature, resulted in a 0.273 g/ dm3 drop of the vitamin C content.

Another 20°C temperature increase, to 65°C, resulted in a vitamin C content of 0.389 g/ dm3 . This shows a 0.032g/ dm3 decrease in the vitamin C content.

Consequently, the data supports the trend that as the temperature of the orange juice sample increases, the vitamin C content decreases. However, it is evident, that as the temperature of the orange juice samples approaches 100°C, the change in vitamin C content is smaller. Thus, the significant drop in vitamin C occurs when the temperature of the sample increases just a few degrees over room temperature.

Consequently, to maintain the unique property of oranges, high vitamin C content, they must be kept at room temperature or refrigerated. However, the orange juice sample that was heated to 85°C did not follow the established trend.

It had a vitamin C content of 0.474 g/ dm3 , which represented a 0.126g/ dm3 increase from the vitamin C content at 75°C. However, for this sample, the orange juice used was made a day later than the juice used for previous trials. Thus, wanted to

see if the error of using a new juice was creating this anomaly. Hence, the new juice was titrated at 45°C and 55°C, and the recorded data stated that the vitamin content was 0.496g/ dm3 , and 0.481 g/ dm3 , respectively. Even though all of the new vitamin C content values were higher than before, they did follow the relationship? as temperature increased, vitamin C content decreases. Thus, it was determined that this was caused by the systematic error of using two different orange juices. Likewise, it can also be concluded that each individual orange has a unique vitamin C content. Ultimately, the scientific reason behind this trend, that the rise in temperature decreases the vitamin C content in orange juice, is that ascorbic acid is easily soluble in water ("Vitamin C"). Oranges are composed of 80 to 90% of water (Schweitzer). Consequently, when heated, because of its solubility, the Vitamin C in the orange juice leaches into the water. The vitamin C the orange juice has, is transferred to the water. As a result, the vitamin C content in the orange juice decreases. (Fredericks). Additionally, the higher the temperature, the faster the water particles move. As a result, they absorb the Vitamin C in the orange juice faster, maintaining the trend of decreasing vitamin C content. In the lab, there was a main systemic error; two different juices were prepared with the same type of orange. This caused all the data points collected with the second juice to be higher than the ones from the first orange juice. However, this did not make the results inconclusive. By collecting extra data points using the new juice, the trend was able to be further supported: as temperature increases, vitamin C content decreases. Nevertheless, each orange carries its unique vitamin C content.

Initially, all oranges were assumed to have the same content of vitamin C.

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After this discrepancy, this assumption was proven to be wrong. Another assumption made, was that the temperature of the orange juice stayed constant throughout the titration. However, because of the procedure and available materials, it was impossible to stabilize the orange juice at a certain temperature. Also, during the experiment, there was heat loss to the environment. Hence, this represented a random error. Yet, this did not affect much the results obtained, since the data stilled followed the accepted trend.

There were also other smaller random errors. When measuring the volume of the solution, the measurement can always be 1 or 2 mL more, or less than the actual value.

Second, the exact endpoint of the titration was never the same in all the trials, as it was determined by observation. Yet, this had a low 2.69% of percentage uncertainty and did not change the accepted trend. Thus, these random errors were not very significant. The lab had various strengths, starting with the feasibility and safety to execute it in a high school lab in 10-hours. Also, all the chemicals were prepared at the lab, from the standard solution to the titrant, so all values and concentrations are correct and exact. Even though sulfuric acid was used, all the safety regulations were put in place to ensure a safe procedure. Moreover, the lab took into account the environmental harm, neutralizing the chemicals with sodium thiosulfate before disposing of them. Furthermore, enough triiodide solution was initially made, so the same titrant was used for all trials. Also, accurate and precise measuring devices were used.

A 25 mL graduated cylinder to measure 25 mL of juice, and an electronic balance with glass around it. Finally, enough trials and different temperatures where measured to be able to show a clear trend with reliable results. Nonetheless, there were some

weaknesses in the lab. Firstly, it was assumed that all, and only, the ascorbic acid was oxidized in the titration. However, there was no way of ensuring that this assumption was fully met. Similarly, the equipment to heat the orange juice allowed for heat loss to occur. Also, it was impossible to get the orange juice to an exact temperature. Another weakness, and a random error, is that the end point of the titration was determined by observing a change in color. Yet, this was left to the human eye, making it impossible to always have the exact same end point. Finally, the drop sizes of starch were never the same, since they were poured with a pipette.

However, as starch is an indicator, it did not have a significant effect on the results.

The two most important improvements that should be made are regarding the orange juice and the equipment to heat the juice. Firstly, to avoid the systematic error of higher data points, one large orange juice sample should be made to use for all the trials. Moreover, as the environment is warm and may begin degrading the Vitamin C in the juice, all the trials should be completed one after the other. If this is not possible, the juice should be stored in a refrigerator for not more than a day. Second, to decrease the heat lost from the orange juice to the environment, a flask with a lid with a hole could be used to titrate the sample. Also, the experiment could be performed in a closed environment with constant temperature and no wind. Furthermore, to decrease the random error of not being able to achieve an exact temperature, the orange juice could be heated at a lower strength to get as close as possible to the desired value. However, regarding the temperature, the error could be minimalized, but in the lab conditions, it could never be completely eliminated.

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Ultimately, to reduce the random error of not always having the same end point, two people can observe the change in color.

This way, they can corroborate on when the end point is. Nonetheless, because the human eye measured the end point, it will never be completely accurate, as we are not machines. Another improvement to the experiment is that the number of trials per temperature could be increased to ensure that the data collected is completely reliable. By adding more trials, you are reducing the random error of measuring 1-2mL less or more than the actual value.

Similarly, even though the percentage uncertainty is relatively small, to reduce this, the sample size of the orange juice could be increase to 40mL. However, the decrease in the percentage uncertainty would be so small that it would not justify using another 15mL of a substance that is better used as a nutritious drink for breakfast. Finally, as an extension of my lab, the effect of temperature on the vitamin C content of other citrus fruits and vegetables that are known for their vitamin C concentration should be tested; the same titration could be performed but with lemon, lime and tangerines.

Moreover, the effect temperature has on vitamin C supplement pills could be seen.

Lastly, the effect that long periods of storage has on orange?s vitamin C content could also be evaluated. If oranges were harvested from the same tree, then they would be tested with the same titration, as soon as they are harvested, and five, 10, 15 and 20 days later.

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REFERENCES 1. Ascorbic Acid Oxidation. Chem Wiki UC Davis. N.p., n.d. Web. 8 Mar. 2016. <http:/ / chemwiki.ucdavis.edu/ @api/ deki/ files/ 12112/ =AscorbicAcidOxidation.png>.

2. Fredericks, Jonae. "Nutrients in Water After Boiling Vegetables." Live Strong. N.p., n.d. Web. 2 Mar. 2016. <http:/ / www.livestrong.com/ article/ 541047-nutrients-in-water-after-boiling-vegetables/ >.

3. Helmenstine, Anne. "Vitamin C Determination by Iodine Titration." About. N.p., n.d. Web. 27 Feb. 2016. <http:/ / chemistry.about.com/ od/ demonstrationsexperiments/ ss/ vitctitration.htm# showall>.

4. "Orange fruit nutrition facts." Nutrition and You. N.p., n.d. Web. 27 Feb. 2016. <http:/ / www.nutrition-and-you.com/ orange-fruit.html>.

5. Schweitzer, Kate. "13 Flat-Belly Foods to Beat the Bloat." Marie Claire 19 July 2010: n. pag.

Web. 2 Mar. 2016. <http:/ / www.marieclaire.com/ health-fitness/ advice/ a5107/ water-rich-foods-to-beat-bloat/ >.

6. "The Titrimetric Analysis of Vitamin C." N.d. Chem UCLA. Web. 2 Mar. 2016. <http:/ / www.chem.ucla.edu/ ~bacher/ CHEM14CL/ Handouts/ Titrimetric_Handout.pdf>.

7. "Vitamin C." Pub Chem. National Center for Biotechnology Information, n.d. Web. 1 Mar. 2016. <https:/ / pubchem.ncbi.nlm.nih.gov/ compound/ ascorbic_acid# section=Top>.

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SPECIFIC HEAT CAPACITY OF ALCOHOLS IN A HOMOLOGOUS SERIES

By I gnacio Gonzales The aim of this experiment was to research the relationship between specific heat capacity and the amount of carbons in an alcohol. To do this different alcohols were heated in a microwave and their change in temperature was recorded and. The specific heat capacity was then calculated. It was found that as the more carbon atoms an alcohol, the lesser its specific heat capacity is.

perfumes, etc. We sometimes even consume alcohol in drinks (humans can only drink ethanol) (BBC). However what are alcohols really made up and how do?

Alcohols are organic compounds (compounds that have carbon atoms) that contain a hydroxyl functional group. In other words alcohols are organic compounds that have hydroxide and their general formula is ROH (Bylikin).

Different alcohols

RESEARCH QUESTION: How does the specific heat capacity of an alcohol change along the homologous series as the amount of carbon atoms in the alcohol is increased?

Alcohols are present in our day to day life, they are on our fuel, some of our makers, on some medicine,

have different amounts of carbons.

These form a homologous series of alcohols. In a

homologous series, compounds have similar physical properties some of these properties may vary slightly along the series as the compounds grow.

(Homologous Series).

In the case of alcohols, they are most known by their reaction with oxygen molecule in order to combust. However they have other properties they share, none have color, they all are neutralized with water and they react with sodium to create a salt (BBC).

In terms of bonding, all alcohols contain intermolecular forces (IMFs) such as hydrogen bonding due to the oxygen and hydrogen in the hydroxyl functional group it contains and

dipole dipole bonds due to the negative charge of the hydroxyl (mistegutch).

However since they are in a homologous series as the alcohol goes up in the series it will have more atoms per molecule this will mean that there will be greater london dispersion forces. This explains why physical properties of alcohols in a homologous series can be describing in a ascending trend.

The density, melting and boiling points of alcohols depend on the IMFs. The more IMFS the greater these physical properties increase.

Other physical properties that follow this trend are solubility, refractive index, and conductivity.

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tested to see if it works.

temperature was heated and using the known value of 4.18 J/ gK as the specific heat capacity of water, the energy transfer was calculated for each cup. To reduce uncertainties and random error, the energy transfer of each individual trial was then averaged.

This was the average energy transferred in 20 seconds by a microwave.

MEASURING THE INITIAL CONDITIONS OF SUBSTANCES

CALULATING SPECIFIC HEAT

In order to get accurate results there initial conditions of each individual cup were tested.

First each empty cup was weighted using a balance and its mass was recorded.

Then the each substance was served to its corresponding cup and the new mass was measured.

This was done in order to calculate the mass of the substance used, when the mass of the empty cups where subtracted to the mass of the cups with their corresponding substance.

The initial temperature of each cup was also measured.

CAPACITY

METHODS (OF DATA COLLECTION PROCESS): SETTING UP THE LAB In order to start the lab properly and prevent further complications all materials where gathered before starting, cups were label (5 of each substance) and the microwave was

MEASURING ENERGY TRANSFERRED In order to find the change in specific heat capacity it was necessary to find the amount of energy transferred by the microwave. To do this five cups of water were heated for 20 seconds in the microwave (the same amount of time each alcohol was going to be heated). Since energy equals the product of the mass, the specific heat capacity and the change in temperature (Q=mc?T), after the 20 seconds water was heated the

Once this had completed it was time to find out the specific heat capacity of alcohols.

Preforming this was quite similar to the previous step.

The microwave was left to cool for approximately 5 minutes. Then the five cups of the first alcohol (methanol) were heated for 20 seconds.The temperature of each of the cups with water was recorded. Its change of temperature was then measured recorded. The equation Q=mc?T was rearranged and the c coefficient which stands for specific heat capacity was isolated. Then the specific heat capacity was calculated using the average energy transferred found in step three. Once again the average of the specific heat capacity found in each trial was found in order to reduce uncertainties. This was then repeated for the remaining three alcohols (Ethanol Propanol and Butanol).

the alcohols remained pure they could were placed in separate beakers at the end of the lab in order to be able to reuse them on another experiment. Paper cups were dried out and recycled. Last but not least, safety googles were used all the time for precaution.

The graph above shows a negative correlation between the number of carbons in a carbon chain and the specific heat capacity of the substance. This means that as the substance in

Table 4 Is a much more simple data table, this one it contains the processed data. In this case it is the average specific heat capacity of each substance.

Furthermore each calculation contains its absolute uncertainty found using the min max method and a Percentage error analysis indicating how close each value was to the accepted value.

the homologous series had a greater amount of carbon atoms in the carbon chain then the specific heat is lower meaning that less energy is needed to heat them up.

SAFETY, ENVIRONMENTAL & ETHICAL CONSIDERATIONS All substances were used in a carefully manner, since 25

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CONCLUSION The aim of the experiment was to discover how did the amount of carbons the carbon chain of a substance the homologous series of alcohols affected the specific heat capacity of an alcohol. It was found out that as the alcohol in the homologous series contains a larger carbon chain, the specific heat capacity decreased, it requires less energy to be heated up. This was shown in the results as Methanol (with 1 carbon atom per molecule) came out to have a specific heat capacity of 2.52J/ gK, ethanol (with a a chain of 2 carbon atoms per molecule) had a specific heat capacity of 2.46 J/ gK, 1-Propanol had a specific heat capacity of 2.42 J/ gK and 1-Butanol with the most carbon (a chain of 4 carbon atoms per molecule) had the least specific heat capacity, 2.31J/ gK. Fortunately there were no outlier in the lab, the data had un uncertainty of .43, although this might seem small figure amount of uncertainty, the date

was no to precise as the results consisted in small amounts too.

My results agree with the theoretical values, further more this explains why as alcohols in a homologous series increase they become more volatile. There was a percentage error analysis of the results in order to compare them towards real values.

Methanol had 0.51% of Error, Ethanol -1.35% , Propanol-.56% and Butanol 0.02% of Error. All of this errors are minuscule, this signify that the results found were very accurate. The Literature values of specific heat capacity used in order to calculate this were 2.533 J/ gK for Methanol, 2.430J/ gk (University of Wisconsin Stevens Point), 143.96 J/ molK or 2.38 J/ gK for propanol (?1-Propanol.?), and 41.0 cal/ molK or 2.31 J/ gK for Butanol (Stenutz). The small magnitude of on all the errors suggests that the data collected is very accurate and therefore reliable.

Additionally most of

the error values were negative, this means that most of the values obtained were less than the theoretical. It could appear to be a systematic error however this error is due to random errors because the percentage error of Methanol is positive (.51% ), if it were to be a systematic error then it all values should have been in the same direction.

Regarding to random errors the uncertainty of the lab was Âą.43J/ gK. Although this might seem a small value it was very significant.

Due to the fact that the range of data collected was small so the uncertainty could alter values in a way that the trend could vary. For example the 2.52J/ gK (the experimental specific heat capacity of methanol minus the uncertainty is less than that of 1-Butanol.

DISCUSSION: Overall the results were pretty reliable.

Although the uncertainty results was significant and could have affected the data the error

when each experimental value was compared to the theoretical value was very low, it ranged between 1.35 % more and 0.56% less. This shows that the data was very accurate. The little amount of percentage error was not just systematic error. Since some percentage errors were positive and others negative, there had to be some random error too.

However the random error was extremely small due to the fact that each measurement had 5 trials. Still there were some possible sources of error. One problem was that the microwave does not always heat evenly all parts therefore maybe some of the cups received a little bit less energy than others. This increased the uncertainty in each measurement.heated together and their temperature was recorded one by one then some of the cups lost a bit of energy before their final temperature was measured.

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Furthermore the microwave did not cool completely in between trial therefore the surroundings of each upcoming trial could give some energy to the substances measured.

However none of this errors were significant, they did not affect the data collected.

Regarding experimental errors, one experimental error was that some energy was lost to surroundings when the final temperature was measured. Its effect on the data collected, Since the alcohols where heated five at a time, but their final temperature was measured one by one, the last alcohols to have its temperatures tested lost more energy to their surroundings. This give a lower reading of Finally temperature hence a lower amount of change in temperature which leads to a lower experimental value of specific heat capacity. This way the range of values of specific heat capacity increased, hence the uncertainties calculated using the min max method also increased. This caused the data to tend to be lower than what it really is, hence it is a systematic error. For improvement on

design, each cup should be individually heated.

Another experimental error was that the microwave doesn't heat evenly. This affected the data collected as the microwave was the source of energy used in this experiment. The fact that it doesn't heat up evenly would signify that different beakers would gain different amount of energy thus decreasing the accuracy of results. This also widened the range of the data and this once again increasing the uncertainty of the results.

Moreover, also linked to this experimental error, the microwave was still hot between trials. This made the alcohols gain some energy from surroundings before being heated. Meaning that in some cases the surroundings (temperature of the microwave before heating the alcohols) gave some energy to the alcohols, this caused the energy transferred to be slightly higher. For both these errors, it is suggested to use a hot plate instead of a microwave and heat each beaker for 20 seconds.

It should be interesting to analyze deeper on this topic and test the same in other homologous series to see if in these other series the specific heat

capacity is inversely proportional to the to the number of carbons in the carbon chain of the organic compound.

Furthermore it would also be interesting to investigate about the difference between the position of the hydroxyl functional group in the compound affect the alcohols specific heat capacity. Do 1-butanol and 2-butanol have the same specific heat capacity?

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REFERENCES 1. "1-Propanol." Wikipedia. Wikipedia, n.d. Web. 4 Mar. 2016. <https:/ / en.wikipedia.org/ wiki/ 1-Propanol>.

2. BBC. "Alcohols." BBC News. BBC, n.d. Web. 30 Mar. 2015. <http:/ / www.bbc.co.uk/ schools/ gcsebitesize/ science/ triple_aqa> 3. Bylikin, Sergey, et al. "10.1 Fundamentals of Organic Chemistry." Chemistry: Course Companion. 2014 ed. Oxford: Oxford UP, 2014. 235-47. Print.

4. "Homologous Series." : Organic Chemistry. N.p., n.d. Web. 30 Mar. 2015. <http:/ / www.ivyroses.com/ Chemistry/ Organic/ Homologous-Series.php>.

5. Misterguch. "What intermolecular forces are present in alcohol?" Socratic. N.p., 29 June 2014. Web.4 Mar. 2016. <http:/ / socratic.org/ questions/ what-intermolecular-forces-are-present-in-alcohol>.

Stenutz, Roland. "Butanol."

6. R. Stenutz. N.p., n.d. Web. 4 Mar. 2016. <http:/ / www.stenutz.eu/ chem/ solv6.php?name=butanol>.

7. "Organic Chemistry: Homologous Series." IB Chemistry Web. N.p., 2016. Web. 8 Mar. 2016. <http:/ / ibchem.com/ IB16/ 10.13.htm# anch3>.

8. University of Wisconsin Stevens Point. "Some Specific Heat Capacities." N.d. PDF file.

Link to file: http:/ / www4.uwsp.edu/ chemistry/ tzamis/ chem105pdfs/ specificheatcaps.pdf

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Investigating the Evolution to Multicellularity: The Effect of Centrifuge Speeds on the Cell Clumping of Yeast

By Alexandr a Nichols

Research Quest ion: What is the effect of spinning rate with variations of 1000 rpm, 3000 rpm, 5000 rpm, 7000 rpm, and 9000 rpm, Âą1 rpm on the effect of speed of yeast cluster formations measured qualitatively through size of yeast clusters when yeast species (Saccharomyces cerevisiae), temperature (30 ÂşC), time spent in centrifuge (10 seconds), and brand of centrifuge (VWR Scientific Micro Centrifuge) are kept constant?

Abst ract Multicellularity has consistently proven itself to be advantageous in the evolutionary race. Natural selective pressure has often favored increasing complexity in modern organisms and many of the components necessary for multicellularity, such as programmed cell death, are present in our unicellular ancestors.

This investigation sought to explore how selective pressure can drive a unicellular organism towards multicellularity.

To answer the question, Saccharomyces cerevisiae was grown and spun in a centrifuge at five different speeds. Only the yeast which settled to the bottom of the tube was selected for the next reproductive cycle, and in this way yeast with the highest tendency for clustering was favored. After one, two, and three weeks the yeast cells were observed under a microscope and and clustering patterns were noted and photographed.

In conclusion, this experiment illustrated that there was a slight correlation between the speed of the centrifuge and the formation of yeast clusters. In the later weeks,

the beginnings of yeast structures had begun to form, both globular and snowflake formations were equally suited to multicellularity.

However, due to the short time period given for this study, further investigation would be required for more conclusive results.

Extensions on this investigation may involve another selective force, such as a rotifer, to increase selective pressure. This extension could explore advantages and disadvantage to multicellularity in the face of a predator.

Purpose of Invest igat ion

t he

This investigation sought to prove a statistically significant correlation between stronger selective pressure and more rapid evolution through the use of a centrifuge at varying speeds. By altering the selective pressure to become stronger through faster rpm speeds, only the yeast most inclined towards clustering will be selected for the next round of reproduction. Results from this experiment could illustrate the significance of rapid selective pressure on the evolution of unicellular organisms.

Furthermore, it may reveal which

geometric patterns formed in yeast aid in survival and would be advantageous to further generations. These findings could indicate a tendency towards certain types of symmetry in modern multicellular organism today and possibly help define the parameters of multicellularity for future research and experimentation.

Survey of Experiment al and Theoret ical W ork Done Saccharomyces cerevisiae, also known as baker?s yeast, is one of the most popular single celled Eukaryotes studied by scientists.

Due to its rapid reproduction rates? parental cells complete a cycle in less than two hours? this species is ideal for studying evolution. These fast rates of reproduction lead to a higher total number of mutations and greater genetic diversity. Consequently, an evolutionary process which historically can take hundreds of thousands of years may be studied by scientists in mere weeks.

Additionally, because they change shape in each phase of the cell cycle, cell cycle phases are easily identified in this species and thus

facilitating scientist?s study ("Saccharomyces cerevisiae."). Yeast cells are benign and thus readily available, generally posing no threat to the researcher.

S. cerevisiae is also commonly used in yeast genetics due to its similarity in cell structure to animal cells. This similarity is especially notable during the cell cycle and the presence of chromosomal structures known as telomeres. Not only that, but yeast cells are also widely studied due to their safety. Yeast cells are benign and thus readily available, generally posing no threat to the researcher.

Historically, unicellular organisms have been at a disadvantage due to the limited opportunities for variation present. Most unicellular organisms replicate asexually, through cloning. Thus, the only opportunities for variation would arise from mutation.

Thus, multicellularity posed an advantage in that it allowed for organisms to replicate sexually, which introduces a different set of genes, further increasing variation, and involves the shuffling of alleles. Thus because multicellularity has provided such a large advantage to organisms, it has evolved independently at least 25 different times (Grosberg).

Multicellular arrangements were advantageous in that they allowed for division of labor and the specialization of cells, which eventually can allow

for controlling of exchange with environments outside the cell (Ratcliff).

Furthermore, in the case of yeast cells, the geometric arrangement of the cells--hence the term: snowflake yeast--affects their fitness (Libby).

Reproductive division of labor is present in these yeast cells in that the clustering cells fall to the bottom of the incubation tube so that they may survive and the single yeast cells are reduced in number.

However, although the cell death rate increases with certain cell arrangements, the number of cells and groups that survive overall are higher.

Thus, the cell division of labor by programmed cell death evident in the snowflake clusters eased the trade-off between snowflake settling and increasing growth rate. The programmed cell death evident in many multicellular organisms is successful because it allows for the number of cells in the clusters to be regulated, rather than a constantly reproducing clump.

In order to ensure I had the necessary materials in place to conduct the experiment, I contacted the original scientist who designed the experiment, William Ratcliff. He was able to provide the unicellular dried yeast spores necessary, as well as the agar media. He also was able to provide a new strain of yeast which he was experimenting with

that could possibly evolve multicellularity more quickly. Additionally, he was an integral part of the experiment in that he provided insight especially through his published scientific journals. When initially preparing for the experiment, I realized there was an error in the design of the experiment. The original experiment I had planned to mimic required a shaking incubator, which was not available to me at the time. Accordingly, I decided to utilize a centrifuge as the principal selective force rather than the shaking incubator, in order to ideally drive selection more quickly and work around the lack of materials.

I planned that each day the experiment would take about an hour and a half.

However, during the preliminary trials in which I began growing separate colonies of yeast in the YPD media, I noticed that often, especially in faster rpm speeds, that a sort of white film would develop in the yeast overnight. In other test tubes containing the yeast, solid white masses would also begin to grow in the yeast. I hypothesized that these growths were due to contamination, and upon further research I suspected they could be another strain of yeast known as kahm yeast, which often appears as harmless white film on foods. In order to avoid this contamination in the final experiment, I ensured that the tin foil was

covering the test tube at all times, except in the short period of time in which the yeast was being transferred. I believe this made a significant difference and reduction of contamination in the final experiment.

Furthermore, at each stage in the experiment small samples of the yeast were kept in order to portray any significant differences that would emerge by the conclusion of the experiment. These samples were also held in case contamination occurred at any later step in the experiment, so I would not have to start over. I wanted to ensure that there was enough variation in centrifuge speeds such that there would be a very small chance of plateau and that the difference between the fastest and slowest rpm speeds would be significant.

Finally, a colorimeter was used at the end of the experiment in order to gather more quantitative data concerning the prevalence of multicellular growth through the density of the yeast solution.

M at erials Used The materials used for the experiment included 1 paper of unicellular yeast spores of size 2cm and a YPD+ Agar Media of 6.5g.

10 standard-sized glass concavity slides were used, as well as one sterile multi-well culture dish. 1 incubator and one centrifuge were used, each standard sized. A

micropipette (size 1mL), 375 centrifuge tubes (1.5mL each), 10 coverslips, one standard compound microscope, 1 roll of aluminum foil (75 ft²), 4

Erlenmeyer Flasks of 1000mL, one autoclave, one standard forcep, 25mL of distilled water, a 5mL serological pipette, 1 standard heated stir plate, 20g dextrose of YPD liquid media, 20g peptone of YPD liquid media, 10g yeast extract of YPD liquid media, 50 25mL test tubes and one 1mL Colorimeter were used for the experiment as well.

M et hodology A) Creation of the Agar 1. The bag of premixed YPD agar in the kit was needed.

2. 150 mL of distilled water was added to an Erlenmeyer flask of 250mL. The flask was placed on a heated stir plate on medium heat.

3. The packet of YPD agar (6.5g) was added to the flask 4. The flask was autoclaved for 20 minutes at 121 ºC 5. The petri dish plates were laid onto an ethanol-cleaned table. Just enough agar to cover the bottom of the petri dish was added.

6. The petri dishes were covered immediately after pouring. The petri dishes dried in 5-10 minutes.

B) Streaking the Yeast from Spores * Notes: yeast incubation will take about 2-4 days using an incubator set to 30ºC. unicellular dried yeast spores are included in the kit.

1. The foil package containing Y55 (unicellular) yeast spores was opened.

2. The forceps were sterilized using an open flame.

3. The paper was removed from the package using the

4.

5.

6.

7.

sterilized forceps.

The filter paper was unfolded and placed on the culture plate of YPD agar using the forceps and the plate was labeled.

The agar plate was moistened using about 50µL of liquid YPD. The sterile forceps were used to streak the paper on the agar. This was repeated for each agar well in the petri dish.

The paper was left on the plate and incubated at 30ºC

C) Sterilization of the Water 1. At least 150 mL of distilled water was poured into an Erlenmeyer Flask of 250mL. 2. The water was autoclaved for 50 minutes at 121 ºC 3. The water was removed from the autoclave and allowed to cool overnight.

D) Suspension of yeast in liquid 1. 1 mL of sterile water was poured into a microcentrifuge tube.

2. A sterile loop was used to scrape of a small clump of yeast from the Y55 agar plate.

3. The loop with the yeast was inserted into the microcentrifuge tube and twirled.

4. The tube was labeled Y55 stock.

5. The process was repeated 25 times.

6. The tubes were grouped into five groups of five and each group was labeled with a trial number 1-5.

E) YPD liquid media * Note: 25 test tubes of YPD media are needed everyday of the transfer.

YPD liquid media may be bought.

However, for this experiment, the liquid media was made using a simple procedure using 20 g of peptone, 20 g of dextrose and 10 g of yeast extract.

1. These three ingredients were dissolved into 1 L distilled water in a 2 L or larger Erlenmeyer flask using a heated stir plate, until completely dissolved 2. The final volume was brought up to 2 L using distilled water.

3. The 2 L of YPD media was autoclaved for 15 minutes at 123ºC 4. The YPD media was allowed to cool overnight in the refrigerator 5. Once the liquid media had cooled, the media was divided equally into four 1000 mL Erlenmeyer flasks.

6. The four flasks were stored in the refrigerator.

F) Inoculation of the yeast 1. 25 test tubes were obtained.

2. Each tube was labeled with the centrifuge speed and trial number. Remember that there are five trials for each of five rpm speeds.

3. Each test tube was filled with 5 mL of YPD liquid media 4. 100µl of the unicellular yeast culture was transferred from the microcentrifuge tubes using the micropipette into the first test tube. This was repeated for the rest of the trials and centrifuge speeds 5. The 25 test tubes were incubated overnight at 30 ºC G) Selecting for Multi-cellularity 1. 5 test tubes of the 1000 rpm speed were obtained.

1. Using the micropipette, 5 mL of YPD media was removed from the test tube and transferred it to the first micro centrifuge tube. The tube was labeled with the trial number.

2. This process was repeated for the remaining trials 3. The five tubes were centrifuged for 10 seconds at the 1000 rpm speed.

4. The upper 90% of media at the tube was discarded into a biohazard trash can.

5. The leftover yeast in the tube was transferred to another test tube with fresh YPD media, and labeled the test tube with the trial number and centrifuge speed.

6. This process was repeated with the other centrifuge speeds.

7. The tubes were inoculated at 30 ยบC overnight.

8. This process was repeated daily for three weeks.

H) Observing the evolution 1. After the first week, one drop of yeast from 1000 rpm speed was placed onto a concavity slide and covered with a coverslip 2. The yeast was observed under a microscope at high power.

3. Any clusters of yeast cells were noted, specifically, in size and number.

Dat a Collect ion

Evaluat ion

by tin foil it is possible that external bacteria could have entered the yeast solution and affected the reproductive success and fitness of the yeast.

This investigation was thorough and consistent in the transfer of yeast everyday at the same time each day, allowing each cycle of yeast an equal amount of time to This experiment could be improved settle and reproduce.

This in the future by determining a more consistency ultimately aided efficient measure of calculating the of multicellular constraining extraneous variables percentage clustering yeast in the sample. throughout this experiment.

Furthermore, the use of precise Furthermore, this experiment could apparatus, such as a micropipette also be greatly improved by simply that measured in micrometers, continuing the experiment for a allowed for minimal error in longer period of time. Even two more weeks could alter the measurement and allocation of yeast in test tubes, further reducing conclusion of this experiment and extraneous error. However, there result in more conclusive results were some significant limitations in that align more closely with the this experiment. One limitation previous findings of Prof. William which severed the scope of these Ratcliff. A possible extension to results was the time constraint. this experiment would be the introduction of a predator, such as a Because the selection was only applied for three weeks, there was a rotifer, to the multicellular and limited amount of time for the yeast unicellular S. cerevisiae organisms. to develop multicellular By observing the behavior of the characteristics. Thus, this could predator towards the organisms and their reactions, explain the one could form limited a hypothesis as variation in Sample Calculat ions: to the [(clustered yeast cells)/total yeast geometric evolutionary arrangement cells]*100=percentage of clustered yeast advantage of present in [(2)/(90)]*100= percentage of clustered multicellularity the final yeast in the case of a week three (0.02)*100= percentage of clustered yeast more specific yeast selective 2%= percentage of clustered yeast samples. pressure.

Another Previous studies have suggested limitation of the yeast is the randomness with which the that multicellularity rendered some samples of yeast were chosen. predators unable to prey on these There was no way to ensure that the organisms and thus was an added to multicellularity small sample of yeast chosen for benefit (Grosberg). documentation was representative of the yeast colonies as a whole. In Conclusion the future, more trials could be used in order to reduce the influence of a Exploring the varying effects that possible outlier in these samples. the speed of a centrifuge has on the Furthermore, error could have rate of evolution of a single celled organism was the aim of this arisen in this experiment mainly through contamination of the yeast. experiment. By invoking a strong Although in general throughout this selective pressure to some groups experiment the yeast was covered of yeast and a weaker selective

force to others, the originally unicellular yeast responded differently. Although in the first weeks of the experiment the selective pressure did not appear to have a significant effect on the clustering of the yeast, the last week of the experiment did illustrate a significant increase in the clustering of yeast. Thus, the centrifuge certainly added selective pressure in that it allowed for a more rapid convergence towards the multicellular ideal. However, because there was not a strong correlation between the speed of the centrifuge and the percentage of clustered yeast, it is likely that even the slowest speed of the centrifuge was a strong enough selective force to result in heavily clustered yeast.

This conclusion is also likely because in Ratcliff ?s original experiment, the formation of multicellular yeast took at least six weeks, whereas in this experiment, similar results were obtained in only three weeks (Ratcliff).

Because the principal difference in selective pressure was the use of a centrifuge in this experiment, it is likely that the centrifuge is the cause of the more rapid evolution.

As evidenced in the data, after one week only small clumps of two and three yeast cells had begun to form.

However, it was after the final week that the most conclusive results were drawn. After week three, more than half of all the cells present were in clusters, with a slight trend towards higher clustering rates with faster centrifuge speeds. Similarly, the colorimeter illustrated a higher density of the yeast solution as the centrifuge speeds increased.

Although separately, the two data sets do not hold much weight, when evaluated together, their similar results indicate not only greater reliability but also a stronger

likelihood of yeast clustering with higher centrifuge speeds. Although these are by no means conclusive results, they certainly must be taken into consideration.

In order to evolve multicellularity, the clusters of yeast which formed needed to be both variable, in that they appeared in different shapes and sizes, and the variation had to be heritable and affect fitness.

The yeast clusters which appeared in the slowest rpm speeds were relatively small, only two or three S. cerevisiae in each cluster, and had yet to develop the signature ?snowflake? branching pattern that had been present in earlier experiments of this nature.

However, towards the end of the experiment, a geometric branching pattern was a more common formation, although globular clusters were also still prevalent. Because both yeast clusters were evident in both globular and snowflake formations, it is likely that because the artificial selection had not yet required strong clustering to survive, both variations were equally adapted to survive. Because this experiment was only conducted for three weeks, it is unlikely that cell specialization or programmed cell death had begun to develop, as it would in a true multicellular organism.

However, these characteristics were unable to be observed due to the fact that under a microscope one is unable to differentiate between living and dead cells.

It is important to consider the differences between cell clustering and true multicellularity when evaluating the larger context of this experiment.

While it is widely accepted that clustering of cells is the first step to multicellularity is the clustering of cells, complex multicellularity, such as presence of tissues or organ systems, is much more difficult to achieve. The gene regulation necessary for complex multicellularity makes the transition far more difficult than the transition to cell clustering. In any case, the results obtained from this experiment do align closely with results from other published experiments, especially those of Professor William Ratcliff, who originally coined a variation of this experiment and introduced the findings to the scientific community in 2011. However, he used gravity as the primary artificial selective force whereas this experiment used centripetal force

through a centrifuge.

In conclusion, overall these results do suggest a slight correlation between stronger selective force? portrayed here as a centripetal force? and more rapid evolution towards multicellularity.

Furthermore, yeast cells showed no significant preference for snowflake over globular clusters in the experiment. However, further experimentation is needed before drawing conclusive results.

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2. Grosberg, Richard, and Richard Strathmann. "The Evolution of Multicellularity: A Minor Major Transition?" University of California Evolution and Ecology. UC Regents Davis, 10 Aug. 2007. Web. 28 Sept. 2015.

3. Heidenreich, Erich. "Adaptive Mutation In Saccharomyces Cerevisiae." Critical Reviews In Biochemistry & Molecular Biology 42.4 (2007): 285. Advanced Placement Source.

Web. 25 June 2015.

4. Libby, Eric, et al. "Geometry shapes evolution of early multicellularity." PLoS Computational Biology 10.9 (2014). Science in Context. Web. 4 Aug. 2015.

5. Milius, Susan. "Multicellular life arises in a test tube: evolution experiment pushes one-celled yeast to go multiple." Science News 16 July 2011: 11. Science In Context.

Web. 25 June 2015.

6. Milius, Susan. "Multicellular life from a test tube." Science News 31 Dec. 2011: 30.

Science In Context. Web. 25 June 2015.

7. Ratcliff, William C., and Michael Travisano. "Experimental Evolution Of Multicellular Complexity In Saccharomyces Cerevisiae." Bioscience 64.5 (2014): 383. Advanced Placement Source. Web. 25 June 2015.

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9. "Yeast genetics." World of Microbiology and Immunology. Ed. Brenda Wilmoth Lerner and K. Lee Lerner. Detroit: Gale, 2007. Science in Context. Web. 4 Aug. 2015.