Timstar | WF Education Group

Delivery charges

FREE delivery on all orders* of £75 and over. Orders of less than £75 are subject to a £7.50 delivery charge (within UK mainland).

We aim to dispatch all stocked items ordered before 11am, on the same day.

* Delivery to Scottish Highlands and Islands is subject to a surcharge. Please, contact Customer Support for an estimate.

Carriage Surcharges

Certain chemicals e.g., lithium, potassium, methanol, bromine etc, may now only be transported by ADR vocationally trained drivers. As such, we have implemented a carriage surcharge of £12.50 if an order contains these chemicals.

All chemicals with the surcharge are clearly highlighted online. Any over-sized or weighted items may be subject to specific delivery charges, for help and advice email us at customer.support@wf-education.com

Need advice?

Please, call our friendly Customer Support team (Mon - Fri, 8.30am - 5pm, excl. Bank Holidays) on 01743 812 200 for advice on your delivery options, prices, and product selection. We offer additional delivery options including guaranteed next day.

We also have an experienced Technical Team to answer all your questions regarding our products, troubleshooting, or any health and safety queries.

You asked, we listened !

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The site has easy access to our product categories and bestselling products for an optimal browsing experience; as well as new product highlights, a quick quote function, and live stock levels with instant updates to guarantee you total visibility of our range.

Explore the new Resource Hub inspired by experts which includes blogs, useful ‘how to’ videos, buying guides, advice, and practical downloads, and much, much more...

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Take

√ Cheaper, (a lot cheaper) to purchase compared to most traditional stills on the market.

√ Easy to install.

√ Requires no electricity (unless you choose a pumped system).

√ There is no descaling needed.

√ There is nothing to break, requiring expensive replacement.

√ Removes all impurities, (including chlorine ions).

√ Constant, even delivery of purified water (a pressurized tank is included).

√ It even comes with its own tap!

AVERAGE COSTS OF RO VERSUS A TRADITIONAL WATER STILL

RO water purification*

Traditional water still

Initial cost of unit (£) £299 £1,000+ (£3,000 - £5,000 range for higher output models)

Replacement accessories (£) (Filters, pk) £45 (condenser/boiler/heater) £300£500 each

Electricity input (kW/ hour) None 3 kW

Cost to run per hour** None £1.02 (£7.14 for 7 hours running)

Water output (L/h) Approx. 1 litre Approx. 4 litres

So, although the water output for the RO is lower than the traditional still, this can be improved with the use of a tank storage system, where the tank is filled at 1 L/hour but once full, at the point-of-use, you will have 9 litres to draw on immediately. (The tank will be continually topped up if the unit is on, and there is an auto shut off when the tank is full).  *Timstar

What are the benefits of an RO system, compared to a traditional still?

a look at the Timstar Resource Hub for all you need to know about your deionised water options!

HERE IS AN IDEA OF HOW MUCH ELECTRICITY A REVERSE OSMOSIS SYSTEM COULD SAVE YOUR SCHOOL

* Based on current prices (January 2023) the average UK electricity price = 34p per kWh.

√ The average traditional water still requires an electricity supply of 3 kW/hour.

√ Running a traditional water still for 7 hours per day would use 21 kW of electricity at a total cost of £7.14 (0.34 x 3) x 7).

√ If, for example, in a busy prep room, the still is on for 3 days per week, then the electricity cost to run it would be £7.14 x 3 days which is: £21.42 per week, £85.68 per month (based on a 4-week month).

A reverse osmosis unpumped system requires NO electricity.

There is a reduction of around 20% in water usage too!

All you need to know is here…

Matt Blake Product Specialist

Microscopes are important pieces of equipment and are one of the most influential scientific inventions ever made. The invention of the microscope opened up a new world of discovery and study of the smallest things. Microscopes have played a huge part in science and, as they are configured to suit different applications, it is important to ensure that you purchase a microscope that is well-suited to your application. Remember, microscopes can be used across all areas of science. Here are some ideas of how you might use them in chemistry and physics.

√ Displacement – microscale

√ Brownian motion

Microscale displacement of silver

EQUIPMENT:

• Copper wire

• 0.1 M silver nitrate solution

• Cavity slide

METHOD:

Search ‘Camera’

• Pipette

• Microscope (x40 objective)

• Clear sticky tape

1. Tape the wire across the cavity of the slide.

2. Place the slide under on the microscope stage and focus in until you get a clear image on the x40 objective.

3. Add 1 or 2 drops of silver nitrate solution to the cavity.

4. Watch the reaction occur (may be slow to start).

THE SCIENCE BIT…

This demonstration can be interpreted in different ways depending on the curriculum point and age of the students:

√ The reactivity series of metals:

MOST REACTIVE LEAST REACTIVE

In its simplest interpretation, since copper is more reactive than silver it will displace silver in the reaction:  Silver nitrate + copper → copper nitrate + silver

Thus silver crystals will form in the solution, and can be observed ‘growing’ under the microscope.

Other scientific interpretations:

√ Metallic structure and bonding of metals, using silver crystal formation as an example of metallic structure.

√ Simple electrochemical circuit:

Silver (Ag+) ions pull electrons off the silver crystals, which in turn remove electrons from the lump of copper (Cu) which produces Cu2+ ions, thus setting up a simple electrochemical circuit. For each copper ion that forms in solution, two silver ions will add to the silver crystal structure.

The ionic half equations are: Ag+ + 2e- → 2Ag and:  Cu→ Cu2+ + 2e-

The CLEAPSS GL125 guide has some useful additional information in selecting microscopes specifically for Key Stages 3, 4 and 5

Brownian motion

Brownian motion describes the random movement of particles suspended in a liquid or gas, originally discovered by Robert Brown in 1827, looking at pollen grains in water.

EQUIPMENT:

√ Light microscope with 40x objective (10x eyepiece) lenses

√ Solution of milk and water, whole or semi-skimmed milk works well (approx. 10 cm3 water with 2 - 3 drops of milk)

√ Microscope slide/microscope cavity slide and cover slip

METHOD:

1. Place 1 - 2 drops of water/milk solution onto a slide or cavity slide if available.

2. Add a coverslip – try to avoid air bubbles.

3. Place the slide under the microscope and turn the condenser so that there is minimal light coming onto the image.

4. Focus the image (remember you are looking for milk and water particles – not an easy combination to see), try focussing on a prepared slide first and then swap it out for your Brownian motion slide.

It is the use of contrast and focus that allows a good view of the fat particles of the milk moving in this demonstration and it can be tricky to get right. You may have to play with the light levels on the stage (condenser) as well as the focussing. The key is patience and calmness.

Milk fat particles

Our product specialists are happy to demonstrate our range of microscopes.

Products:

The Motic SFC-100FLED is a robust microscope with high-quality optics and LED illumination, it runs cool and has built-in rechargeable batteries.

The Motic F-1115 LED is simple to handle with magnification up to x100 and a built-in Abbe condenser.

The Motic B1-220E-SP binocular microscope features semi-plan objectives, magnification up to x400 and a built-in mechanical stage.

MI55310

MI55325

MI180200

Catherine Mellor Product Specialist

A good video of Brownian motion with milk can be found here!

£135.00 £179.50 £550.00

Looking for high-quality physics equipment? Try the Frederiksen range.

Not everybody is meant to be a scientist. However, Frederiksen believe that everybody has the right to learn. They provide science equipment that is well-designed, simple to use and tailored for teaching. Their aim is to engage students to learn and teachers to teach!

Signal Generator Linear Air Track Power Supply

Code SI130500

Developed in conjunction with physics teachers and designed specifically for education, this unit provides all the functionality you need for physics teaching. One really useful feature for those less familiar with using signal generators is that for basic use, you just operate two buttons: One for frequency and one for amplitude, that’s it!

Code TI68740

A superb quality air track, suitable for elastic and inelastic collisions, momentum, speed and acceleration measurement.

Code EL150308

A simple, robust and reliable power supply, ideal for basic electricity experiments. Offering stepped adjustment of both AC and DC with 1 V between the steps.

Search ‘Frederiksen’

Making potassium manganate (VII) crystals (KMnO4)

Ingredients:

• Eye protection/gloves/apron (KMnO4 will stain skin and clothing)

• Saturated solution of KMnO4 - Solid hazards: Oxidising; irritant; respiratory irritant; environmental hazard. Solution hazards: irritant.

• Beaker

• Pencil (or similar)

• Cotton/thread

• Tweezers

Method:

2. Attach the cotton to the pencil with the free end hanging in the solution.

1. Pour the saturated KMnO4 solution into a beaker.

3. Place the pencil across the top of the beaker.

4 Leave for a few days for the crystals to grow around the cotton.

5. Pull out the cotton and pick off the crystals, using the tweezers, when they are the desired size.

Notes/tips:

The saturation point for KMnO4 is 6 g per 100 mL, so ≥ 6 g in 100 mL will give a saturated solution at 20⁰C     You can use these homegrown crystals as a starting point for diffusion and convection current experiments.

Making EDTA solution in 1000 mL

Titrations involving EDTA: The disodium, dihydrate salt is commonly used for titration work (0.1 moldm-3 or 0.05 moldm-3 solutions are suitable). For accurate work see also details on standardising EDTA solutions.

Molecular weight 292.2438 g/mol

Ingredients:

• EDTA (ethylenediaminetetraacetic acid)

• Sodium hydroxide pellets

• Hydrochloric acid (2 moldm-3)

• Distilled or deionised water

• 1000 mL measuring cylinder

• 1000 mL beaker

• Magnetic stirrer

Method (to make 0.1 moldm-3 solution):

1. Add 29.22 g EDTA to approx. 800 mL of distilled or deionised water and stir (using a magnetic stirrer).

2. Check the pH. The pH needs to be 8 for EDTA to dissolve.

3. Add sodium hydroxide solid, a little at a time, until the pH reaches 8. (If it overshoots and becomes too acidic, add a little hydrochloric acid to bring the pH back to 8).

4. Once the EDTA has dissolved, make the solution up to 1000 mL with distilled or deionised water.

Formula C10H N O

Health and safety for technicians

Health and safety in the department is everyone’s responsibility. Every member of staff has a duty of care and as such should never ignore anything that might put students or staff at unnecessary risk.  Individuals will not be held liable in law for an accident/incident, unless they were acting negligently, or willfully disregarding health and safety guidance having been given the appropriate training.

It is your employer’s duty to organise appropriate health and safety training for new employees whether they are new to the school, the department, or even the specialism. You should be taken through procedures for evacuation, risk assessment and so on - this training can be given by a senior technician or department member tasked with such duties.

If your school or academy trust is a member of CLEAPSS or SSERC (Scotland) there is a wealth of helpful information pertaining to health and safety that you will have access to.

Tasks that require supervision and training before you can carry them out unsupervised include:

√ Fire training

√ Eye irrigation in the event of a chemical splash

√ Operating equipment such as fume cupboards/EHT power supplies/Van der Graaff/autoclaves and other pressure vessels

√ Biological and chemical waste disposal including microbial waste and hazardous chemical waste

√ Handling chemical spills

The list is extensive and can be found in CLEAPSS guide G234: Induction and training of science technicians.

See page 45 for our Risk Assessment module

In addition to specific training (that will occur as you meet these tasks over the course of your employment) general health and safety should always be at the front of your mind.

This includes consideration of:

Your own safety: Safety of others:

• Using Bunsen burners

• Working in the chemical store or preparing chemicals

• Moving heavy equipment

• Prioritising tasks when interrupted or asked to do something urgently. You can only work as fast as you feel safe. Never leave a task unfinished if it is unsafe to do so.

• Trip hazards in the corridor or lab (e.g., uneven carpet)

• Slip hazards (e.g., wet floors)

• Fire doors being propped open

• Missing fire extinguishers

All of these occurances need reporting to relevant staff members (or the site team) as soon as you see them. Do not assume someone has already noticed and reported it!

Safety of others in practical sessions:

If you are in a lab during a practical session and students are acting in a dangerous manner, it is your duty to stop them first, and then call the teacher over to deal with the incident/behaviour.

Never be afraid of telling students to stop if what they are doing is dangerous, and do not assume the teacher has seen what is going on.

Have on hand spare hair ties, for students whose hair needs tying back. If they refuse, then stop their practical work and report them to the teacher – flaming hair is not a good look!

If your school operates a ‘no student in science department between lessons (lunch/break)’ policy, then you can ask them to leave. Always question anyone on site you do not recognise.

And finally, never allow students into a lab unsupervised, even if it is to reclaim a lost pencil case.

Health and safety is a vast area of employment law and there is a wealth of further information online at gov.uk and at CLEAPSS/SSERC where it is broken down in to more specific areas relevant to science and Design and Technology. However, if you are not sure or not confident about any task, seek help first!

See page 26 for MSDS explained Think safe. Act safe. Be safe.

WHY INVEST IN DATALOGGING?

Making datalogging easy-to-use and to understand, the Phywe Cobra SMARTsense range is the sensible choice for schools!

Datalogging is the process of collecting and storing data over time, looking at data sets, data points and logging intervals. This seamless collaboration between science, technology and data analysis is becoming a vital tool in education, for teachers and students alike.

The possibilities for datalogging within education are plentiful. Whether it is investigating the effect of light on photosynthesis or logging temperature changes over time, Timstar has a considerable range of datalogging sensors that can support scientific enquiry, can be integrated

into required science practicals, or used to further enhance the learning experience.

WHAT ARE THE EDUCATIONAL BENEFITS OF DATALOGGING?

Develop students’ higher-order thinking skills

Encourage their science argumentation skills

Students work like ‘real’ scientists

Inquiry-based learning

Develop other skills such as numeracy and literacy

Works very well with EAL students

Links the computing and science curriculum

‘Using this equipment helps bring science alive and develops students’ confidence with using technology that is different from what they usually encounter in class.’

The benefits of datalogging

Our extensive anecdotal evidence suggests that datalogging assists students to take their science work more seriously. They also become more aware of the need to take accurate measurements when working on varied investigations.

Another benefit was that their understanding of graphs and reporting data and their findings improved quickly when seeing ‘science’ in real-time.

Reasons to invest in datalogging with Timstar…

Over

FREE and easy-to-use software! Compatible with most devices

FREE resources supporting teachers and technicians

FREE technical support! Helpful guidance and expert advice

Excellent service and friendly customer support team

Our range includes the FREE measureAPP software which has hundreds of experiment

Having worked alongside third party lab fit-out companies, Timstar wished to be able to offer customers a truly turnkey in-house service – dealing with one friendly team, from render to reality.

We are an expert ISO 9001 accredited team, drawing expertise from our in-house space designers, layout and space planners, education sector health and safety specialists as well as consulting regularly with teachers and technicians.

We can provide fit-for-purpose science spaces, either for new build or the renovation of existing spaces.

INSPIRATIONAL LEARNING ENVIRONMENTS

We understand that for most staff, redesigning an educational space may only happen a few times during a career. For us it’s our passion and we will happily support you and share our expertise to create spaces that work.

A Timstar lab provides space for a mixture of practical and non-practical activities and includes consideration of demonstrations, presentations and discussion, individual, small group and class work, experimentation, and research.

We create attractive, engaging laboratory spaces to stimulate pupils’ learning, alongside well-planned preparation areas for teaching and technical staff.

CUSTOMISED LAB DESIGN

We will work with you to create an inspirational new science laboratory. Our specialist design team will consult with you and your colleagues to make layout suggestions which will maximise your space and budget. We have taken care that the elements we offer are robust and appropriate for school use and place importance on providing quality furniture and equipment that will stand the test of time. For full fit-out projects or multiple spaces we will illustrate our ideas using CAD drawings and if appropriate 3D colour renders to help you visualise the proposed space.

‘School science laboratories are an expensive investment and are expected to last for many years.

A poor design will impact on generations of pupils, teachers, and technicians.’

The Association for Science Education

A TURNKEY SERVICE

Once a design is approved, we will then discuss programming the work at a time to suit you, and hand-over to our Project Management team.

Our team can co-ordinate the supply & installation of your school science laboratory furniture and equipment. Our solution includes the co-ordination of all trades – an invaluable service for busy school staff. When your space is complete, and if desired, our team can

unpack and stock your space with essential items from the Timstar range.

Uniquely, Timstar can offer a complete Chemical Store service. Our in-house expert can assist you with ordering all that you will need to stock your store, and then unpack and put away all chemicals following all Health and Safety requirements.

Please, see page 22 for more information.

FULLY COMPLIANT WITH HEALTH AND SAFETY REGULATIONS

The services, equipment, chemicals and materials, used in schools’ laboratories make them a ‘danger area’ under health and safety regulations.

We select all our furniture, fixtures, and fittings according to Department for Education (DfE) Building Bulletins and recommendations by ASE/CLEAPSS/SSERC.

The Timstar team can offer ongoing support and technical assistance regarding equipment post installation.

Our experienced team will pay attention to all aspects of your space including:

√ Department of Education requirements

√ Plumbing and water supply

√ Ventilation

√ Gas and extraction

√ Fixed and mobile furniture

√ Acoustics and sound proofing

√ Power and data cabling

√ Storage

√ Focus walls

√ And more…

If you would like to discuss a project with our team, please, scan and complete the form.

As easy as PCR - biotech for everyone!

We work with Edvotek®, the world’s leading supplier of safe, affordable and easy-to-use biotechnology kits and equipment designed specifically for education.

WHAT IS IT?

A way of increasing the number of copies of a specific region of DNA that you want to study.

Once you know the region of DNA that is of interest, you need to find it to analyse it further. With around 3 billion bases making up human DNA (for example), finding the area you are interested in (made up of say 200 bases) can be a very hard task (like looking for a needle in a haystack!).

In order to make the search easier we can increase the number of copies of the ‘interesting’ area using PCR, (a bit like increasing the number of needles so they are easier to find in the haystack).

HOW IT WORKS

PCR stands for Polymerase Chain Reaction, and using some specific, and generic chemicals, and heating and cooling we can finish with billions of copies of the area of DNA under study.

Main steps to the PCR process:

1. Denaturation: The 2 DNA strands become un-bound from each other and separate.

2. Annealing (binding primers): Primers – small pieces of DNA specific to the ends of the area of interest - bind to the ends of the target region, identifying the area of interest.

3. Extension (copying and extending the DNA): This means adding free nucleotides* onto the end of the primers to extend the (complementary) strands of DNA (making new, identical DNA).

Steps 1 - 3 are continuously repeated until, after about 30 cycles, there will be approximately 1 billion copies of the DNA region of interest.

*nucleotide: single phosphate-sugar-base unit, a string of nucleotides forms one strand of DNA, (two complementary strings twist together to form the double helix). Free nucleotides are added to the reaction mix as dNTPs.

All of this can be performed in a thermal cycler, such as the Edvotek Edvocycler Junior (BT200806).

Once you have put the ingredients into the microtubes, the thermal cycler will do the rest, leaving you with a sample that you can visualise, by performing electrophoresis (a sort of biotechnology chromatography): loading the samples into a gel through which they travel according to size.

Sample loaded into wells

Our

DNA size reference (each line represents DNA of a known number of base pairs, so you can identify the size of your sample)

Amplified DNA sample

Our quick guides will help you to get the best from your biotechnology practicals

Lucienne McCallum Product Specialist

A simple distillation set up, using jointed glassware

A staple of the chemistry curriculum, this makes a great demonstration of a separating technique for two liquids (distillation).

• Common mixtures to use in the round bottom flask are: cola; 50% ethanol with food colour added; ink in water.

• Gentle heating of the mixture will allow the liquid with the lower boiling point to evaporate from the flask, which is immediately captured and condensed in the Liebig condenser (a glass jacketed tube allowing water to cool the contents of the tube). The liquid is then able to drip into the beaker via the receiver, leaving the higher boiling point liquid in the round bottom flask.

Search ‘Jointed glassware’

If you have ideas or suggestions of other equipment set ups you would like to see, please, let us know!

Quickfit® joints are designed to be used without the need to use grease, as the grease can be a source of contamination in an experiment.

Scan for a handy table about the features and benefits of Quickfit®

Did you know Timstar supply Lascells products?

Looking for British designed and manufactured physics equipment?

One of the great joys of the world is understanding how something works and this is the cornerstone of Lascells thinking. They design physics apparatus with ease of use, durability and associated learning outcomes in mind. They aim to reduce setup time and unnecessary complications so that teachers can spend valuable lesson time preparing students for a future in physics and engineering.

EXPERIMENT IDEAS FOR THE LASCELLS E-FIELD DETECTOR

A way of detecting not only electrostatic charge, but also whether the charge is the same or different (negative will light blue, positive will light red), and an improvement on the delicate gold leaf electroscope that has been in use for many years.

It is more robust than the gold leaf electroscope and simple to use, and there are different accessories available to help to demonstrate charge.

Here are a few ways you can use the E-Field Detector:

Observing positive and negative charging of rods

You will need:

• E-Field Detector (EL220000)

• Acetate or glass rod

• Ebonite or polythene rod

• Silk/cotton cloth (duster)

Set up the E-Field Detector as directed (remember to connect the grounding wire and reset to zero).

Rub the acetate or glass rod with the cloth and bring the rod close to the detector – the red lights will light up indicating a positive charge.

Repeat with the ebonite or polythene rod and the blue lights will light up indicating that there is a negative charge on the rod.

How charge decreases with increasing distance

You will need:

• E-Field Detector (EL220000)

• Rod

• Silk/cotton cloth (duster)

Set up the E-Field Detector as directed (remember to connect the grounding wire and reset to zero).

Charge up the rod with the duster, and bring the rod close to the detector so the maximum number of lights light up. Slowly pull the rod away from the detector and you will see the number of lights lit decrease, showing that the electric field is decreasing with increasing distance.

√ You can attach a voltmeter to the E-Field Detector to give quantitative measurements, using the sockets on the detector (make sure you connect it the right way round, check the instructions).

The charge proof plane

You will need:

• E-Field Detector (EL220000)

• Charge proof plane (EL220010)

• Various cloths

The charge proof plane is a useful accessory to check the charge left (or gained) by the type of cloth you are using to charge the rods with.

Set up the E-Field Detector as directed (remember to connect the grounding wire and reset to zero).

Rub your cloth of choice onto the charge-proof plane and hold it near to the detector, it will light in the colour of the charge that was on the cloth (red for +ve, blue for -ve).

Observing charge by induction

You will need:

• Field Detector (EL220000)

• Ebonite rod and duster

• Charge separation rods (accessory – EL220030)

Set up the E-Field Detector as directed (remember to connect the grounding wire and reset to zero).

Place the charge separation rods, touching end-to-end, in front of the detector.

Bring a charged ebonite rod close to the end of the charge separation rod (furthest from the detector).

Holding the plastic stands only (not touching the metal rods) separate the charge separation rods.

Test each against the E-Field Detector to see that they now have opposite charges.

√ The negatively charged ebonite rod will repel electrons from the first metal separation rod towards the second one (the one nearest the E-Field Detector) – polarising the metal separation rods. When you pull the two rods apart, the one nearest the ebonite rod will be positive, the one furthest away from the ebonite rod will be negative.

For more than a century, the OHAUS name has been synonymous with precision and reliability. Here at Timstar we are happy to partner with OHAUS to bring you a full range of balances which are perfectly suited to your lab environment.

BALANCE TERMINOLOGY

Analytical:

High precision pieces of equipment capable of weighing over a wide range and with accuracies of 1 decimal place to 2 and 3 decimal places, depending on the model and its usage. They are generally reserved for the prep room.

Precision:

Available in a wide range of capacities. Not as precise as analytical balances, but more precise than the average bench or compact scale. They also have a higher capacity than analytical balances, but a lower readability.

Top loading

Often equated with precision balances and named as such, the top pan balance is the most robust but least accurate of the three, the range is higher, but the readability is lower.

COMMON BALANCE FEATURES

√ Locking switch: Locked to secure the delicate internal mechanism during transport.

√ Overload protection: ensures the balance’s durability.

√ Mini spirit level: ensures the balance is level before weighing for accurate results.

√ Calibration function: on most modern balances. Press to calibrate before use.

√ Tare ‘reset to zero’ button: allows you to clear the balance weight prior to weighing (meaning you can ignore the effect of the weighing vessel).

√ Under balance weighing hook: Used for weighing oversized items that do not fit well on the balance pan.

√ Draught shield: Protects the contents on the balance from air currents, creating a stable environment for getting the most accurate mass.

√ Units of measurement: As well as the usual grams measurement most balances offer different units of measurement.

A couple of the less well known are;

√ Parts counting: Parts counting allows you to count very small items into a container and the balance will tell you when you have reached the correct amount.

√ Dynamic weighing: Dynamic weighing is useful for measuring objects in motion, for example: small animals, liquids, free flowing ingredients, volatile chemicals, weighing in an unstable environment.

Search ‘OHAUS’

Navigator

Ruggedly constructed and multifunctional, the Navigator is a powerful balance that can handle a diverse range of weighing applications with features such as fast stabilisation time, overload protection at four times its rated capacity, and easy operation.

Pioneer

Offering accuracy and repeatability in essential weighing applications

Pioneer balances deliver competitive performance at an economical price. Featuring RS232 connectivity for easy communication, a backlit display, and a simple interface for uncomplicated operation.

Scout

Designed for education applications, the OHAUS Scout with large backlit LCD backed by education software is the ideal balance for your classroom. Built to endure demanding classroom applications with superior overload protection, faster stabilisation time, increased capacity, multiple connectivity options and stackable design.

OHAUS Scout Balances...Watch on YouTube!

A range of balances will be needed within the department: easy-to-use robust balances for lower years, higher precision coupled with robustness for GCSE and A level groups.

Large capacity robust balances will be required in physics where measuring the mass of heavy blocks, and a high precision shielded balance is very useful in the chemistry

prep room. It is often handy to have a second small high precision balance that you can use in the fume cabinet for weighing out toxic solids and ultra-fine powders.

See our guide for all the specifications to enable you to make the best choice combination of balances to suit your department’s needs...

Search ‘Balance Buying Guide’

NEW SCHOOL? LAB REFURBISHMENT?

Setting up a department, and prep storage for a new building, new 6th form teaching or a department refurb can be a time-consuming and daunting task. Not only deciding what you need, but once you have taken delivery of the goods and chemicals the task of unpacking products and sorting chemicals into a cohesive and safe storage system can feel overwhelming.

THIS IS WHERE WE CAN HELP...

Working with one of our Product Specialist team right through from your initial inquiry to order placement, we will be on hand to help you to unpack the full order along with our Technical Specialist, Amanda, who will advise you about how to sort the chemicals into correct storage.

At the Bobby Moore Academy in London, we were able to do just that. Due to the size of this order, Amanda unpacked and organised the chemical store and was on hand to advise the department on the correct storage procedures for the chemicals they had bought, from box to shelf; whilst Product Specialist Matt supported them with the equipment unpack, helping the staff at the academy to be as organised as possible before the start of their teaching.

SO LET US KNOW IF YOU ARE SETTING UP

* This service applies to large orders only, with a minimum order value. Please, contact the team for more information.

OR REORGANISING ANY PART OF YOUR SCIENCE DEPARTMENT, AND WE WILL HELP YOU FROM START…TO FINISH!

Timstar can help with your chemicals

DIFFERENT CLASSES OF CHEMICALS:

• Organic chemicals

• Inorganic chemicals

• Flammable chemicals

• Toxic chemicals

• Oxidising chemicals

• Radioactive chemicals

• Explosive chemicals

• Corrosive chemicals

Many chemicals will be a combination of the above.

THE BASIC RULES:

1. When a chemical has more than one hazard associated with it, store it as the most dangerous hazard (e.g., if it is corrosive and flammable, store with flammables).

2. Separate the flammables from the oxidisers.

3. Flammables MUST be stored in an appropriate secure cabinet.

4. Oxidisers can be stored with general inorganic chemicals if they are not mixed with the organics. If inorganic and organic chemicals are stored together, oxidisers must be separated out and stored together as far away from organic as possible.

5. Keep the explosives separate and in a cabinet.

6. Keep large corrosives, e.g., conc acid stock bottles, close to the floor on spill trays where spillage will cause the least hazard.

7. Toxic chemicals can be stored on general shelves of the store if the store is secured.

8. Store radioactive chemicals according to regulation (in a secure cabinet fixed to the wall at least 2m from where people will be working).

9. If the store contains a flammables cupboard, then radioactive chemicals and gas cylinders cannot be stored here.

10. If the flammables cabinet is outside the store and there are no gas cylinders, then the radioactive cabinet can be inside the store (if legal requirements are adhered to).

11. Some chemicals should only be made when needed and disposed of as soon as possible after the practical (e.g., Tollens reagent (silver mirror test); chlorine water: the chlorine will leak from the container).

12. You should have an up-to-date stock list and a risk assessment that covers the use of the storeroom.

SPECIAL CASES:

Sodium, potassium, and lithium metals: These are stored under oil and will be delivered as such. Make sure the oil levels are maintained and that any small pieces of metal remain under the oil. If potassium metal shows signs of yellow crusting it should be disposed of (contact CLEAPSS/SSERC for guidance).

Silicon chloride: once opened the bottle can seal itself (formation of silicon dioxide when silicon chloride is in contact with water in the air) and has the potential to explode in very hot weather. Store inside a secondary container containing a desiccant.

White phosphorous: store under water (change water regularly). Store with Toxic chemicals; keep apart from oxidisers, sodium, potassium.

Bromine liquid: Store inside a secondary container with silica gel. Store with a bottle of 1 M sodium carbonate solution (note guidance has changed from sodium thiosulfate solution), and solid sodium carbonate (hydrated) both in case of spills.

Mercury: Keep in a secondary bottle, in a tray. Keep a mercury spills kit alongside. 2,4-dinitrophenylhydrazine: explosive when dry. After opening this should be stored inside a secondary container on wet sand (or similar) and should be checked regularly. The stock bottle may need to be put into a clear bag to stop the label getting wet)

This is by no means an exhaustive list.

For more detailed information and guidance, visit the CLEAPSS/SSERC websites.

Food tests and enzymes

Food Tests

Food testing in biology is a standard set of procedures which all GCSE students will need to complete, and which is revisited at A level.   The tests are for the presence of carbohydrate (simple and complex), protein, and fat in food.

Generally, it is easy and uncomplicated to set up and can be as complicated or easy for the students as the teacher wants it to be, depending on the foods chosen to be tested.

WHAT TO TEST FOR?

• Carbohydrates (complex: starch): test with iodine solution.

• Carbohydrates (simple, reducing: glucose): test with Benedict’s solution (and heat).

See our recipe for making starch solution on page 40

• Carbohydrates (simple, non-reducing: sucrose): break bonds with hydrochloric acid then neutralise before testing with Benedict’s solution as for simple sugars.

• Protein: test with biuret solution.

• Fats: test with ethanol, Sudan III or greaseproof paper.

FOODS TO USE FOR THE TESTS:

Biological molecule under test

Easy lesson

Complex carbohydrate Starch solution*

Simple carbohydrate (reducing) Glucose solution

Simple carbohydrate (non-reducing)

Sucrose solution

Longer (messy) lesson

Potato/bread

Bread/juice

Any sucrose flavoured drink/squash

Protein Milk Cheese/protein shake

Fat Oil

Butter/cheese

Enzymes

Ah! The dreaded call for an enzyme practical can chill the heart of many a dedicated technician.  Enzymes are biological catalysts that speed up the rate of many reactions in the body, they are substrate specific, meaning that they will only work on certain substances.

Not only that, but individual enzymes also have specific temperatures and pHs that they work best at; add to this the fact that they will denature at high temperatures (the shape of the enzyme will change and will not fit the substrate, so they will not be able to speed up the reaction) and you have a very temperamental activity to deal with.

For example, amylase enzyme will break down starch into glucose, and it should work in the temperature range 20°C - 60°C, but optimum pH can vary from a minimum of 3 to a maximum of 8, depending on the type of amylase you have.

Always make up enzymes in distilled/deionised water. Check the pH and temperature conditions required and ensure that your diluted enzyme is within those ranges. Always test the enzyme with the chosen substrate before use.

Once you have a successful enzyme/substrate combination you should be able to use it many times over about a week (if the enzyme solution is kept in the fridge).

Make sure you do a quick test before each use as ANY contamination of substrate solution with the enzyme solution (even a contaminated pipette tip) will mean the experiment will fail as the enzyme in the substrate solution will break it down (so the test will not work). And yes, we mean as little as one drop in one litre!

For a full list and troubleshooting tips visit our Resource Hub and download our handy guide.

So, it helps to know all you can about the system you are setting up.

What is an MSDS and why do we need it?

Every chemical supplied has a data sheet attributed to it (also known as: safety data sheet, SDS/material safety data sheet (MSDS).

• Different suppliers will put their logos on, but they will all have the same data:

• These are required by law, and you may have to show them in an Ofsted or health and safety inspection.

• It is not intended for these to go into the student laboratory with the chemicals, more that they are a reference point for the technician or teacher.

• Historically these data sheets would have been sent with the chemicals, and some companies still do this, however, it is becoming more common to find them on the website of the company you ordered the chemical from, in a downloadable format. This means that the data sheet can be updated when necessary (e.g., if regulations change) and you always have the most up to date sheet to hand.

What does the Timstar data sheet tell you?

Section 1: Identification

• Product identifier – this is the order code (will change from supplier to supplier)

• Product name – the actual name of the chemical

• CAS number – a number unique to the chemical, supplied by the Chemical Abstracts service. If you google this number (preceded by CAS) you will find a wealth of information about the chemical

• REACH reg. number - an 18-digit number assigned by the European Chemicals Agency (ECHA). It is the most straightforward proof that one company has fulfilled their registration obligation for a substance under the EU REACH regulation

• Molecular formula – the formula and molecular mass of the chemical

• Relevant identified uses of the substance or mixture & uses advised against – this tells you what the product is intended for/not intended for. There is also the supplier’s details and emergency contact

Section 2: Hazards identification

• What hazard classification the chemical is classified as.

• What specific (hazard) labelling the chemical should have, with images. These hazard pictograms are known as CLP pictograms (classification labelling and packaging of substances EU regulations) and they came into effect in 2015 and superseded the CHiP hazard symbols (chemical

hazard information and packaging (for supply)) which were UK specific. Although the symbols are similar the CHP ones should be used now as these are uniform throughout the EU. The CHP regulations are being retained since Brexit, being known as GB CLP

• Precautionary statements:  general advice on what steps should be taken when handling the substance e.g., do not breathe vapour/store in a well-ventilated place etc.

Section 3: Composition

• A summary of the previous information, with relevant regulatory numbers and classifications

Section 4: First Aid

• This section details the first aid measures that need to be taken should an accident happen with the chemical, it also details symptoms to look for and whether any immediate medical attention would be indicated

Section 5: Firefighting

• This section details what firefighting measures are appropriate and what the hazards associated with the chemical being on fire are (e.g., toxic fumes). It also gives details of the advice for firefighters (e.g., keep up wind/ wear breathing apparatus)

Section 6: Accident Release Measures

• This covers personal and environmental protections and precautions in the event of a spill, and methods required for clean-up and containment

√ Hazards √ Disposal

√ Identification of the chemical √ Storage

Section 7: Storage and Handling

• General advice for safe storage, and precautions to take when handling the chemical

Section 8: Workplace Exposure & Personal Protection

• This section deals with exposure limits, in parts per million of the chemical (ppm), for both short (15 minutes) and long term (8 hours) exposure

• E.g. for hydrochloric acid, the data sheet states that exposure limits for 35% HCl for a 15min period shouldn’t exceed 5ppm (or 8mg/m3)

• Section 8 then details the precautions to take to limit exposure (whether that is respiratory/eye or skin exposure) e.g. gloves/respirator etc.

Section 9: Physical & Chemical Properties

• This details the physical and chemical properties of the chemical – what it should look like when you receive it and properties such as boiling point/melting point, its pH , flammability etc.

Section 10: Stability & Reactivity

• How stable/reactive the chemical is and anything to avoid e.g., incompatible with alkalis/potassium permanganate/ reacts with most metals

• What happens when the chemical decomposes (toxic products etc)

Section 11: Toxicological Information

• What kind of poisonous effects (if any) the compound will have if exposed to it in various ways (inhalation/ingestion/in the eye or on the skin)

• LD50 information relates to lethal dose: it is the amount of the compound that when given (all at once) kills 50% of the test group e.g., the LD50 for copper (II) sulfate-5-water for ingestion (oral LD50) is 690 mg/kg for a rat test group

• Other toxic information found here can include the effects of exposure in various ways, and often the threshold at which irritation has been found to occur (in parts per million) e.g., for Hydrochloric acid 5-10ppm will irritate the skin, with severe irritation if exposed to 50-100ppm

Section 12: Ecological

• This section describes any detrimental ecological effects of the substance: toxicity to plants and animals, including aquatic animals. E.g., for copper (II) sulfate-5-water: very toxic to aquatic organisms

• There will be LD50 for aquatic organisms here if data is available

• Also here:

o 12.2 Persistence & degradability: how long the chemical will remain in the environment after release without degrading (so still potentially harmful)

o 12.3 Bioaccumulative potential whether the chemical will accumulate in the environment and show cumulative effects (e.g.: years ago the pesticide DDT was used, the toxic effects

of it accumulated such that the chemicals became more concentrated as the pesticide moved up through the food chain (as it was part of the organism that was eaten), eventually poisoning the top predator (possibly human). Hence the ban on DDT as a pesticide (in most countries)

o 12.4 Mobility in soil – does the chemical travel through the soil (e.g. in solution) – this will be indicated by a keep out of sewer/storm drain/ soil/water note because of the chance of it getting into the soil and causing uncontained issues

o 12.5 Results of PBT vPvB assessment: this is an assessment of the persistence/ bioaccumulation/toxicity (or very persistent, very bioaccumulative) effects of the chemical in an ecological setting. It is required under EU rules for all chemicals which a chemical safety assessment is carried out

o 12.6 Other adverse effects – anything relevant but not already covered in detail above

Section 13: Disposal Considerations

• 13.1 Waste treatment methods detail the ways to dispose (or how NOT to dispose) of the represented chemical: e.g., do not dispose of as domestic waste/dispose of in a licensed incinerator/do not dispose into water courses / neutralise before disposal

• For more detailed disposal of your chemical, especially that applicable to schools refer to CLEAPPS (England, Wales, and NI) or SSERC (Scotland) as there is more flexibility around disposal in educational establishments compared to suppliers/carriers

Section 14: Transport Information

• This section refers to industry classifications and categories for the carrier. Technicians should never be transporting chemicals in their cars without obtaining specialist insurance and permissions

• Also in this section are any considerations the end user should be aware of (allow to settle before opening for example)

Section 15: Regulatory Information

• This section covers the regulations/classifications and hazard information for the chemical. This is where you will find CLP (hazard) pictograms

Section 16: Other Information

• Any disclaimers, dates of revisions and reviews will be here

WF Education Group’s ethos is to provide a hassle-free turnkey service for every Timstar customer - from support and procurement through to aftercare and maintenance - all under one roof.

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We operate from our large Shropshirebased distribution centre that is dedicated to fulfilling customer orders in the most sustainable and environmentally friendly ways possible. With our ISO 14001 accreditation, we are committed to a sustainable future; working with our customers to identify all opportunities to reduce waste, reuse and recycle.

Timstar offers a comprehensive product range, excellent service, technical support, advice on how to set up and run practicals along with supportive resources to save time and ideas to enthuse your students.

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Ideas for using your EHT power supply

Some pieces of equipment get dusted off once a year, used for one practical (the same one each year) and then packed away again. The EHT power supply is often one such item. Here we have a couple of ideas for getting extra use from yours.

EHT – Extra High Tension (power supply)

• Capable of producing 5000 V DC.

• School EHT supplies contain the option of an internal resistor limiting the number of amps to around 0.1 mA (depending on size of resistor). This will increase to 5 mA without the resistor.

• Shrouded leads are used which provides added protection from shock (no metal exposed).

• EHT supplies tend to be safer than HT supplies as the current output is generally lower.

• Make all connections/disconnections with the unit switched OFF.

• Depending on the age and make of the EHT the input and output terminals may look different. Make sure you are clear which terminals you are using and that the unit is safe before using. Check manufacturer’s instructions for your particular unit.

Remember when doing any experiments using the EHT: safety first, always risk assess the procedure, and trial before demonstrating!

GIANT (BIN BAG) CAPACITOR

This is a good way to introduce capacitors to the class, using foil and plastic sheets.

EQUIPMENT:

• 2 x large pieces of bin bag plastic (insulator)

• 2 x large pieces of tin foil (conductor): these must not be larger than the plastic sheets

• EHT power supply

• Microammeter with centre zero, connecting wires, crocodile clips

METHOD:

1. Lay one sheet of plastic on the table.

2. Lay one sheet of foil on top of this, followed by a second sheet of plastic and then a second sheet of foil.

3. Connect one lead to the bottom sheet of foil using a crocodile clip, and the other end to the microammeter and then to the negative terminal of the EHT supply.

4. Connect a second lead to the top sheet of foil using a crocodile clip, and the other end to the positive terminal of the EHT supply.

5. Before switching on make sure you can reach the EHT without touching the foil sheet.

6. Turn on the EHT and increase the power until you start to hear/see sparks on the foil. Turn the power back down until just before this point and switch off the power supply.

7. Switch on the power supply and watch the microammeter.

8. Switch off the supply, remove the leads from the power supply and connect the leads together to complete the circuit (excluding the EHT). Watch the microammeter again.

9. Once you have shown what happens to the microammeter you can re-connect the EHT and increase the power, showing the sparking effect of the capacitor breaking down, electrons are getting across the insulating layer to the second piece of foil so the capacitor cannot store charge.

10. Once you have finished the demonstration, discharge the capacitor as before, remove the EHT from the circuit and connect the leads together. You can then dismantle the circuit completely.

Ref: Institute of physics: creating a bin bag capacitor

EHT and capacitance:

Capacitors are circuit components capable of storing and then discharging charge, like a backup battery - except they won’t generate charge.

Each wire sticking out of the capacitor attaches to a thin metal sheet, with an insulating, dielectric, material between them. The metal sheets charge up but charge cannot pass through the dielectric and is held (stored) until allowed to discharge. You can do this by disconnecting from the power source and re-joining the circuit wires. The charge will be released back into the circuit, until the capacitor is ‘empty’. It can be recharged by replacing the power source.

ADAPTATION OF MILLIKAN’S OIL DROP EXPERIMENT

This experiment, a version of the (Millikan) oil drop experiment, demonstrates how charged particles will move when they are between 2 charged plates, and that they can be held there, in the generated electric field.

EQUIPMENT:

• EHT power supply (Max 5 kV), appropriate EHT safe (shrouded) wires, and crocodile clips

• Metal plates x 2, Insulating pillars x 4

• Thin aluminium foil, cut into small pieces

• Ensure all health and safety guidelines on using the EHT are followed (see page 30). All equipment should be turned off whilst setting up, take care not to touch the plates once the demonstration has started, and switch off before disconnecting the apparatus at the end.

METHOD:

1. Set up the apparatus as shown in the diagram. The plates should be parallel.

2. Attach the bottom plate to the earth connection and the negative EHT port, and the top plate to the positive EHT connection.

3. Place some foil pieces on the bottom plate.

4. Switch on the EHT supply, turn it up until the foil is held (‘dancing’) between the plates.

5. Switch off and allow the charge time to dissipate (voltage output from the EHT to fall to zero) before disconnecting.

SCIENCE:

This is an example of a capacitor with air as the dielectric. When current flows, it charges up the metal plates (top becoming positive, and the bottom negative). As in a capacitor, the electric field lines between the parallel plates will be straight and uniform.

As the foil sitting on the bottom plate becomes charged, electrons will be repelled and the foil will be attracted upwards to the positive plate, where it will be repelled again (like charges) and pushed back towards the negative plate. This will continue until the circuit is switched off and the electric field has gone.

In the original Millikan experiment, an oil drop was held stationary between the 2 plates, and the force acting on the charge on the oil drop was calculated and, by extension, a calculation of size of the electron could be made, making the Millikan experiment a fundamental experiment in the history of the atom.

Ref: Institute of physics

Fruity science

There are lots of experiments that you can do in school using readily available types of fruit. Here are a couple to get you started.

Rates of reaction: rhubarb and oxalic acid

EQUIPMENT:

• Rhubarb stalks (frozen works well)

• Acidified potassium manganate (VII) solution, (approx. 0.1% in 1 moldm-3 sulfuric acid)*

• Beakers (100 mL)

• Measuring cylinder (50 mL)

• White tile

• Stopwatch/timer

• Knives to cut rhubarb

*The exact concentration of potassium manganate solution isn’t critical, but test it before the practical to ensure that it decolourises with rhubarb, you may need to add a little more water to dilute it further if the initial colour is too intense to see a change.

THE SCIENCE BIT…

METHOD:

1. Cut the rhubarb into evenly sized pieces (about 5 cm is good).

2. Add 30 mL potassium manganate solution to a beaker.

3. Place the beaker onto a white tile.

4. Add one piece of rhubarb to the beaker containing the potassium manganate solution.

5. Start the timer.

6. Stop the timer when the potassium manganate solution has turned clear.

You can use this method to look at how surface area affects the rate of reaction (chop a second 5 cm piece of rhubarb in half and put both halves into the same beaker, chop a third piece into quarters etc.); and if you gently heat the rhubarb until it is ‘mush’ and strain it (keeping the filtered liquid) you can look at the effect that changing rhubarb concentration has on reaction rate too, using increasing amounts of rhubarb extract in the manganate solution).

The oxalic acid (C2H2O4)  in the rhubarb reacts with the potassium manganate (MnO4) and releases carbon dioxide (CO2) and water (H2O). The pink/purple potassium manganate solution changes to colourless as a consequence of the reaction (more specifically to a very pale pink, but it will look clear in the concentrations that are being used).

2MnO4– + 5C2H2O4 + 6H3O+ → 2Mn2+ + 10CO2 + 14H2O

HAZARDS:

Potassium manganate, solid (CLEAPSS hazcard 81):

Sulfuric acid (CLEAPSS hazcard 98a): Irritant

Acidified potassium manganate solution (~0.1 moldm-3): Irritant

Note: Oxalic acid in the rhubarb is an irritant, which may be an issue if you are looking at rhubarb concentration.

(Adapted from Royal Society of Chemistry)

If you have your own fruit experiments, why not share them with us, they might make our next edition!

The lemon cell 4.

EQUIPMENT:

• Lemons

• Wires (2 per lemon)

• Crocodile clips (as many as you have wires)

METHOD:

1. Soften the lemon slightly by gently squeezing and rolling it to loosen the juice.

2. Push 1 x copper and 1 x zinc strip into the cut surface (in contact with juice) as far from each other as possible (at least 5 cm and not touching each other).

3. Attach a crocodile clip to each metal strip and attach a wire to each crocodile clip.

THE SCIENCE BIT…

• Copper strip/wire

• Zinc strip/galvanized nail

• Multimeter

• LED

4. Attach the end of each wire to a multimeter set to amps/milliamps.

5. Once you have set up 1 lemon cell, you can attach more lemons in the same way, linking them in series with each other (not in parallel).

6. Swap the multimeter for an LED and, if the lemons have enough power, you will see the LED light up.

The lemon battery works in the same way as electrolysis. The acidic lemon juice (citric acid is the weak acid in lemon juice) is the electrolyte solution, able to carry a charge, and the zinc and copper strips are the anode and cathode electrodes. The lemon provides the power and the circuit is completed by the connecting of the wires and multimeter.

Zinc dissolves in lemon juice, leaving zinc ions (Zn2+) in the juice, while the two electrons (per atom) move through the wire toward the copper. The following chemical reaction represents this oxidation reaction:

Zn → Zn2+ + 2e−

The copper doesn’t dissolve in the juice, and the citric acid (in the juice) partially dissociates, leaving some H+ ions behind. These combine with the electrons at the copper (that arrived from the zinc), to form hydrogen gas, which leaves the system.

This reduction reaction is shown by the equation:

2H+ + 2e  → H2

You might be able to see the hydrogen bubbles at the copper electrode if you swap out the lemons for lemon juice.

Hopefully you will get a voltage of around 1.3 V (but very few amps) for the lemon battery.

OTHER FRUIT AND VEG TO TRY:

• Any citrus fruit: orange, lime, grapefruit, or straight fruit juice.

• Potato (phosphoric acid instead of citric acid provides the H+ ions).

You could have some fun building the BIGGEST fruit and vegetable battery you can, and see how much power you can get, or have a fruit battery building competition and award a prize for the most LEDs lit.

5.

The properties of PYREX® are such that it is possibly the most versatile glass around. It can be safely used over a temperature range from -192°C to +500°C, it has excellent chemical resistance to even the most aggressive acids and bases and both factors have made it the first choice in some of the most demanding scientific applications.

In the school environment PYREX® is an ideal choice because of its resistance to heat. There is far less chance of breaking and ‘hot spotting’ on beakers, flasks and test tubes being heated, and therefore it is a safe alternative to cheaper, less resistant glassware in the market.

PYREX® is made of Borosilicate glass 3.3. The glassware is protected against thermal breakage and mechanical shock because of the slow and careful annealing process during manufacture, and the chemical resistance of PYREX® is excellent, making it an ideal storage container for all your acidic or basic solutions.

The chemical resistant labelling ensures longevity of your glassware, especially pieces that are regularly in the dishwasher. The labelling is clear and a good contrast to show up well whatever solution is inside the container, especially useful when measuring and using equipment like burettes.

THE NAME PYREX® WAS DERIVED FROM THE LATIN: PYRO MEANING FIRE AND REX, MEANING KING – AND NOW YOU CAN SEE WHY!

To find out more about key features of PYREX, visit our Resource Hub and download the table!

Plastics: how to make the right choice

There is no ‘one size fits all’ plastic, and some plastic types are better suited for specific tasks than others.

TABLE SHOWING CHEMICAL RESISTANCE PROPERTIES OF VARIOUS PLASTICS USED IN SCIENCE.

SUMMARY TABLE OF RESISTANCE FROM WORST PERFORMING PLASTIC (RED) TO BEST (GREEN).

Resistance to acids:

Resistance to organics:

For more useful help with selecting the right plastic for the job, download our physical properties of plastics table here

Static electricity!

A fun activity introducing static electricity, something pupils will explore later in the curriculum

EQUIPMENT: (per group)

• Balloons, pre blown up

• Small pieces of paper

• A plastic or acetate rod

• Duster

• Tap with running water

• Paper boat

• Shallow tray

• Bubble mix and straws

• Large tile or smooth surface (lab bench)

METHOD:

1. Pick up the plastic rod and touch it to your head.

2. Using the same rod, touch it to some small pieces of paper.

3. Now hold the rod close to a thin stream of water.

4. What do you observe?

5. Now rub the rod vigorously with the duster and repeat steps 1, 2 and 3. What do you observe this time?

6. Take the pre blown up balloon, rub it on your head and gently pull it away. The hair should cling to the balloon.

7. Using the same balloon, after rubbing it on your head (or on a jumper) repeat steps 2 and 3, and see what happens.

8. Swap out the small pieces of paper for small polystyrene packing beads and (after rubbing with a duster) bring the rod or balloon close to them.

EXTENSION

• Make a small paper boat and put it into a shallow tray of water, use the rubbed rod or balloon and see if you can move the boat without touching it.

• For a similar effect try it with a paper windmill: fold a small square of paper into four to find the centre point, balance this on the pointed end of a pencil held in place on the desk and use the rubbed balloon/rod to try and spin the paper ‘windmill’ without touching it.

• Add some bubble mix to the tile, using the straw blow a bubble in the mix, but don’t lift the bubble from the tile. Bring the rubbed balloon close to the bubble. What happens?

THE SCIENCE BIT…

When the plastic of the balloon or rod is rubbed with a duster or your clothes (or even hair) the balloon/plastic rod will gain electrons and become negatively charged, the material you rubbed it with will lose electrons and become positively charged. The electrons have moved from the cloth to the balloon.

Now that the balloon is charged it will attract the opposite charge of anything it touches or comes close to. Therefore, it will attract them and make them move.

Using the extension activities will encourage further thinking about same charges repelling.

Although electrons will not necessarily have been visited by year 6 students, they will have met the forces of attraction and repulsion with magnets, so charged objects causing movement will have been seen before.

WHY DO WE COVER OUR MOUTHS WHEN WE SNEEZE OR COUGH?

We have all experienced the COVID pandemic, where we were asked to wear masks so that we didn’t ‘breathe on people’, and to sneeze into our elbows so that we didn’t transfer ‘germs’ to other people on our hands. But why?

In this practical you can demonstrate the effect ‘blocking’ has on the distance a ‘sneeze’ would have travelled, and thus help to halt the spread of (airborne) disease.

EQUIPMENT: (per student group)

• Several large sheets of paper

• Two clamp stands and a metre rule (or long stick)

• A spray bottle containing very dilute food colour in water

• Some tissues

• Gloves (or a cutout of a spread hand, on a stick)

• Measuring tape or rulers

METHOD:

SET UP:

Set up the apparatus, with the two clamp stands and metre rule (or long stick) holding a sheet of paper, with more paper covering the bench.

1. Student 1 stands at the end of the bench facing the clamp stand arrangement, with the spray bottle.

2. They spray once towards the paper hanging from the ruler.

3. Student 2 measures the distance and width of the coloured spray on the paper and writes it down.

4. The 2nd (or 3rd) student then holds the ‘hand’ cutout (or their own gloved hand) in front of the spray bottle.

5. The 1st student sprays the coloured water again, and the 2nd student writes down the distance and width that the spray reached on the paper.

6. This process can be repeated holding a tissue in front of the spray bottle (to mimic real life).

7. You can repeat the process using specified distances to see how close the hand or tissue needs to be to stop any spray going past it.

Questions to ask

Did the distance of the hand make any difference to the distance of spray, or the width of the spray?

Could they draw a graph of distance of spray versus hand distance from student 1?

How effective was the hand or tissue in stopping the width of the spray?

This is a nice way for the students themselves to see how effective a tissue, or a hand, is in stopping the spread of microbes contained in saliva when a person sneezes, or coughs. Although it would be a stretch to introduce the role of bacteria, yeast, ‘good’ and ‘bad’ microbes at this level, it would be a nice experiment to return to when that topic is visited later in Year 7 or 8, alongside the handwashing practical. It can also be used as a graph drawing exercise, as another skill provision.

“Coughs and sneezes spread diseases, catch them in your handkerchief”

“Catch it! Bin it! Kill it!”

Introducing the OHAUS Guardian™ 3000 Hotplate Stirrer.

A hotplate stirrer is an important piece of kit to aid a laboratory technician’s daily work. For it to be useful, it must be reliable, robust and easy-to-use. The Ohaus Guardian™ 3000 hotplate stirrer is just the product, having recently been awarded the ASE Green Tick. The unit comes with an optional temperature probe which further improves its performance.

The ASE stated...

The Guardian 3000™ features a bright LCD display with easy-to-read temperature and speed settings, and intuitive icons.

The Guardian 3000™ has a large, easy to clean, ceramic heating plate, (178 mm square), stirs from 80 to 1600 rpm and offers a temperature range up to 500°C. Safety features include a hot top indicator light to protect the user; green indicator lights illuminate when unit is heating and stirring.

Can be used with the optional temperature probe for precise temperature control of your sample

Designed for economical heating and stirring in all laboratory settings

‘The fact that it will heat to a specific temperature and then maintain it is a great feature, and one that would be very useful for the busy lab tech.’

The Medline MS-100 is an analogue hotplate offering a large heating area of 180 x 180 mm with safe controlled heating up to 400°C.

Need help to decide between a heating mantle, stirrer or hotplate? We have written a handy guide to explain all the terminology, features and benefits and with our expert's top picks, to help you to make the right choice!

This is the Cole-Parmer Stuart SHP-200D-S, offering accurate temperature control and protection from over-heating, an easy-to-read digital screen, stirring speeds of up to 2000 rpm and mixing capability of up to 15 litres of liquid.

Scan to view our Hotplate/ Stirrer Buying Guide...

Timstar stock a wide range of hotplates and stirrers, why not take a look?

Hotplates with built-in magnetic stirrers are ideal when heating liquids to distribute heat evenly

Ingredients:

• Soluble starch

• Room temperature water (few drops)

• Boiling water

• 100 mL measuring cylinder

• 150 mL beaker (or larger)

• Balance

• Spatula

• Weigh boat

• Stirring rod

• Pipette

• Heatproof gloves

• Goggles

1. Weigh out 1 g of soluble starch into a beaker.

Method:

3. Boil 100 mL water (measure into a measuring cylinder) and add the just boiled (still very hot) water to the starch paste.

2. Add enough room temperature water to make a paste.

4. Stir to mix and the solution will become clear.

5. Allow to cool and use as 1 % starch solution.

Making a starch solution without using hot water will result in a starch suspension and will not work in your experiments.

Making Agar for diffusion

You may be familiar with agar when used to grow bacterial cultures in microbiology, but a plain, technical, agar also exists which is agar without any nutrients. It can be used as a growth medium if you are adding your own mix of nutrients (for a specific microbiology practical for example) but more commonly it is used to make agar ‘jelly’ blocks for the students to observe diffusion.

Here we describe a method to make coloured agar blocks for diffusion studies.

Ingredients:

• Plain agar (technical agar/ agar agar) 20 - 25 g

• Distilled or deionised water

• Indicator solution 30 mL (see note below)

• Sodium hydroxide solution, 0.01 moldm-3  30 mL (see note below)

• Balance and weigh boat

• Hotplate stirrer

• Spatula

• Stirring rod and pipette

• Heatproof gloves

• Goggles

Method:

1. Weigh out 20 - 25 g (depending on the firmness of agar required) of plain agar powder into a large beaker or flask.

2. Make up to 1 litre with distilled/deionised water.

3. Stir, with heating, to mix and eventually the solution will become clear. This may take some time.

4. Allow to cool slightly (to around 50°C), add the sodium hydroxide solution and the indicator solution and mix.

5. Pour into the desired container and leave to set. Agar will set at around 45°C.

6. Once set, the coloured agar can be cut into blocks ready for the class, the diffusion investigation will require dilute acid (0.1 moldm-3 hydrochloric acid).

Alternative method:

• Make the agar up in water and add an indicator (30 mL) and sodium carbonate solution (30 mL 0.5 moldm-3) when the mix has cooled to around 50°C.

For more information on indicators and diffusion experiments with agar see Resource Hub

Making starch solution (1% for example) in 100 mL

√ ELISA is a way of detecting proteins in a solution, using antibodies and linked to a colour changing enzyme-substrate marker.

√ The protein under test is bound to a solid surface (the bottom of a microplate) in one of 2 ways: directly to the plate (direct ELISA) or via a linked antibody (capture ELISA).

√ It is because of the highly specific nature of antibodies to their targets that this has become a hugely popular tool to detect levels of protein/peptide/antibodies and hormones in solution, and it is widely used in the medical and research industries.

√ Most ELISA kits intended for educational use will be direct ELISA with the base of the plate pre-prepared for the sample protein.

Applications of ELISA include:

1. Testing for antigens – The target antigen could be a virus, a food allergen or a drug.

2. Testing for antibodies in blood serum – examples of this would be HIV testing and COVID tests.

The basic steps to ELISA are:

1. Fix the antigen (protein sample) to the plate (‘coating/capture’).

2. Add a solution to block any unbound areas of the plate (‘blocking’). This can be an irrelevant protein, to which the antibody will not bind, or other solution.

3. Add the specific antibody that will bind to the protein, if present.

4. Add the antibody-enzyme complex.

5. Add the substrate that binds to the enzyme and if products are formed (if the substrate binds, i.e. if the protein is present) there will be a change of colour in the well of the plate.

6. There are kits available where you can also quantify the amount of protein present, using standard curve techniques.

A video is available to show the process using our Simulated ELISA Kit BT190000.

Most of us are now familiar with ELISA as a test for COVID-19

Our product specialists are happy to offer advice and training.

now

Lucienne McCallum Product Specialist

The Van de Graaff generator

The Van de Graaff generator is a staple experiment in almost every school and the basis of every static electricity introduction. From sparking in air to raising the hair, the Van de Graaff is always a winner with students.

SO, WHAT IS A VAN DE GRAAFF?

It’s a way of generating electrostatic charge.

HOW DOES IT WORK?

• The motor is switched on and the lower (negative) roller turns, moving the insulating belt.

• The roller builds up a negative charge, leaving a positive charge on the belt (the excess negative charge on the roller escapes to earth via the metal brush at the bottom).

• The negative charge on the roller also ionises the air between the roller and the bottom (metal) brush, causing more electrons to flow to earth from the brush ends, and allowing the positive ions in the air to be attracted to the negative roller (but as the belt is in the way they add to this charge on the belt).

• As the positively charged belt moves up to the top roller and metal brush (which is in contact with the hollow metal sphere), electrons from the top brush are attracted to the positive belt and move to the tips of the brush.

• The air is again ionised by the motion of the roller and belt, allowing electrons to move to the belt and positive ions to move to the brush.

• The charged belt is in contact with the hollow metal sphere (via the ionised air and the brush) and will discharge to the sphere, leaving it with positive charge.

Warning! At this point in the process the sphere has a large charge on it and anyone touching it will receive an electric shock, as the rush of negative charge moves to neutralise the heavily positively charged sphere.

• Any experiments using a Van de Graaff generator should be undertaken following a risk assessment and training on the machine.

• No one with a pacemaker should be allowed to take part in these experiments.

• Always follow health and safety guidelines (CLEAPSS/ SSERC where appropriate).

1. Pushing the discharge sphere near to the main (charged) sphere without touching it will allow electrons to ‘jump’ across to the charged sphere as they rush to neutralise the charge – you can both see and hear these lightning strikes.

2. When a fluorescent light tube approaches the negatively charged generator, the electrons on the generator flow through the tube and the person holding it. Flowing electrons result in an electrical current, lighting up the light tube. It doesn’t take very much current to light a fluorescent tube!

3. When a student puts a hand on the sphere, the electrons will spread out onto that person as they repel from the other electrons. They are most obvious in a person’s hair because the like charges of the electrons repel each other and cause the hairs to stand up and spread away from each other. As long as the person is standing on an insulated platform, the electrons will not be able to travel down to the ground and their hair will remain standing up.

4. Blow some soap bubbles at the generator. You’ll see a flurry of bubbles rush toward the machine’s sphere, then make an abrupt about-face in the opposite direction. At first, carrying the charge of the person who blew them, the bubbles are attracted to the charged sphere,

which carries the opposite charge. But when that first bubble or two hits the sphere, they absorb its charge and are immediately repelled, popping in the process. Encountering the spray from these burst bubbles, the incoming bubbles will be repelled.

5. Electrostatic induction is how to induce a charge onto an uncharged object: bring an uncharged (insulated) metal ball close to the charged sphere of the Van de Graaff. This forces the electrons in the ball to be attracted to the sphere leaving the further side positively charged. If you momentarily touch the ball, electrons will rush to the ball to neutralise the positive side. Now pull the ball away and it will be negatively charged. You can show it is now charged by demonstrating the effect on small pieces of paper/polystyrene.

6. Conductors and non-conductors: A string connected between an electrostatic generator and an electroscope will not conduct charge, but a metal wire will.

Top tips when using a Van de Graaff.

• A damp environment affects the ability to ionise air molecules, so avoid using the Van de Graaff on a humid or very damp day (the charge collection will not be as good).

• You can use a hairdryer to dry the air around the Van de Graaff before you start to charge the dome.

• Keep the brushes clean and free from dust and debris, as this will affect the air gap between the rollers and the brushes, which is needed to help charge flow.

• Make sure that anyone touching the Van de Graaff is standing on an insulated stool, and if they remove their hand from the machine, they should not replace it as they will get a shock.

Products:

EL62550

EL85100

EXPERIMENTS WITH THE VAN DE GRAAFF.

The Frederiksen, premium Van de Graaff

Our Eisco bestselling Van de Graaff

£485 £335

WF Education Group is a family of brands that has been serving the education and library sectors for over 80 years. A global solution provider for specialist education; we provide products and design spaces to improve wellbeing and learning outcomes.

As well as Timstar, we have three other brands with ranges dedicated to STEM, Design and Technology, Libraries and Learning Spaces, and Sports and Leisure.

Design and Technology

TSL provides solutions and resources which inspire students in Design and Engineering education and prepares them for a modern workplace. We believe that the development of critical thinking, communication and collaboration skills in education is vitally important to solve today’s global challenges and create a sustainable future.

Library and Learning Spaces

A specialist library partner, Gresswell supports libraries with professional resources to efficiently run, helping to support the communities they serve. With 80 years of expertise Gresswell supports the academic literacy, educational, creative, emotional, and reading development of students, teachers, and patrons.

Sport and Leisure

Maudesport supports the development of physical and mental wellbeing through engaging, innovative, and inclusive activities or sports in education and leisure. Creating engaging opportunities through sport and activity-focused spaces, supplies, resources, and solutions to support the acquisition of skills to live healthy, happy lives.

Risk assessment: Mitigate the risks!

What is a risk assessment? It is the process of identifying hazards that may exist, how they may cause harm, and what steps can be taken to minimise them.

In any situation we are constantly thinking about the outcome of our (and sometimes other’s) actions.

What is the result if I drop this bottle?

What happens if I overload that shelf?

We are constantly risk assessing our environment, although we may not always be aware of it. A risk assessment document proves to any investigator that we have consciously thought about the risks, assessed them, and decided if the activity is safe enough to proceed.

Teachers are responsible for risk assessments of their own practical work, there may be some already written that are generic for many lessons, but the teacher must appraise and update these for their own class/lab etc.

Technicians are responsible for risk assessing procedures that they do, for example diluting acids, making gases, transporting radioactive items.

You can use a simple table to categorise the overall risk of an activity, comparing the chance of an accident happening, to how severe the outcome would be if an accident did happen:

WHAT DOES THIS MEAN?

If the chance of the risk happening is very unlikely and if it did happen the severity was negligible, the risk would be deemed low (therefore ‘safe’). For example, the chance of a wall shelf, sited at the back of the laboratory (away from students) falling off the wall: with the shelf correctly secured to the wall the chance of it falling is very low, and the chance of it injuring people is also low, as no one sits near to it. Therefore, this would score ‘low’ on the risk assessment. However, if the shelf were sited near to students, the chance of injury if it did fall would be high, this would then score ‘medium’ on the risk assessment.

Conversely, if the chance of the risk happening was highly likely and the outcome if it did happen was severe, then the risk is ‘high’ (and thus unsafe) e.g., an unruly class setting light to gas taps with the outcome of burning someone or setting fire to the lab.

Once the risk assessment is done, you can mitigate for the risks. In the example above, the gas would not be turned on before the practical, and the class would not be left unsupervised.

Most risks can be mitigated with planning and attention to the individual situation, with plans in place should anything go wrong (extra supervision for that particular class and someone waiting at the emergency gas stop button should an incident occur).

The Timstar summer supertech meet

Looking for a great value training day? Want great workshops, an exhibition with manufacturers and experts, and networking opportunities with likeminded science staff? Why not book onto one of our events?

We are delighted to be hosting two events, at fantastic venues in 2023. Please, register as soon as possible to guarantee your place. Places are limited and will be offered on a first come, first served basis.

We can’t wait to welcome you. Don’t miss out!!

Make connections with Timstar...

WHAT’S INCLUDED?

√ 3 workshops (we have listed some of the ones on offer)

√ Time to spend speaking to our suppliers in the marketplace

√ A raffle

√ A lunch and refreshments throughout the day

√ The chance to network with other local science technicians and teachers

√ The opportunity to chat with the Timstar team

THE WORKSHOPS WILL INCLUDE (MAY DIFFER AT EACH VENUE):

Microbiology

Robotics

Fun chemistry experiments

SAPS - Biology

Eisco - Physics

L J Smith Microscope Servicing

Lascells – Physics

All this for just £40pp!