Applied Science AQA/Ideas for Investigations

Suggested titles for scientific investigation:

These ones come directly from the syllabus, which means that you can be pretty confident that they can provide the range of methods / variables required.

Investigate the use of immobilised cells in bioreactor.

Immobilise yeast cells by entrapping them in spheres of alginate gel and then use the yeast cells to perform enzyme experiments.

Investigate the factors that affect the efficiency of electroplating using copper

Investigate how the concentration of the solution, the temperature, the presence of other ions in solution (using small volumes), the shape of the electrode and the condition of the electrode surface affect the electro-deposition rates.

Investigate how electrochemical cells work and the factors that can change the voltage output

Make a number of different electrochemical cells by pairing up various metal/metal ion half cells and then investigate how the voltage changes depending on the salt concentration, the size and shape of the electrode and the temperature of the salt solution.

Investigate the factors that affect fermentation in the brewing industry

Use yeast to investigate how different substrates, temperature, pH, nutrients and a range of media can be used in brewing.

Investigate the properties of modern shampoos

Determine the relative viscosity, pH, foaming ability, cleansing effectiveness, and oil-emulsification abilities of different shampoos.

Investigate the response of LDRs

Determine how the resistance of selected LDRs is related to different intensities and different wavelengths of light.

Investigate the factors that affect the output of a wind turbine

Determine the useful energy generated by model turbines with different numbers of blades, blades of different shapes and blades of different areas.

Investigate the factors that affect reaction time

Use real or virtual reaction timers to determine the effect of various factors such as caffeine, practice, age, gender, etc, on reaction times.

Alternatively, learners/centres may choose their own investigation(s), but centres are strongly advised to contact AQA tvq@aqa.org.uk in order to confirm the suitability of the investigation in allowing learners to access P, M and D grading criteria.

The scientific investigation should be set in a particular vocational context (as part of an assignment brief) and applied to a specific industry either locally, nationally or internationally.

Other ideas:

Here is a list of suggestions for Science Investigations from a previous version of this Wikibook, for the old syllabus. Just remember... make sure that an investigation has the potential to score on all of the criteria before getting too deep in. (Teachers - please edit this list - especially if you know that one of these ideas just won'd work.)

You don't need a client - but having one can help provide a good focus.

Chemistry

Non-coalescing drops

Client: Some industries will mix liquids by cascading one liquid into another, assuming mixing will be complete. These drops may prevent complete mixing and need to be investigated.

Recent research has shed light on this phenomenon: The fast-moving shiny drops that skid across the surface of soapy water. Detergents play a crucial role – but how does the concentration of detergent affect the drops? What about ‘non-ionic’ detergents? What about a surface of anionic detergents and drops of cationic ones?

Challenges: Making drop-producing apparatus, Researching the chemistry of detergents, Assessing the numbers of drops

Viscosity kinetics

Client: Chemical producers who rely on reactions in solution will need to know how viscosity might affect rates of the reaction.

Many chemical reactions depend on molecules colliding, so slowing the rate of collisions will slow the rate of the reaction. In solution, the viscosity of the solvent can affect the reaction by slowing the collision rate, but it does not work for every reaction. The reaction between calcium carbonate and acids is highly dependent on viscosity, but when acids react with thiosulphate the viscosity seems not to be a factor.

Challenges: Assessing the viscosity of solutions, Researching and investigating the kinetics of reactions.

Marble chip reaction with acid

Client: Chemical industries using heterogeneous reactions will need to know how the rate of reaction can be altered.

How is the rate affected by various factors (e.g. surface area, temperature, concentration, stirring, viscosity, ionic strength). Estimation of surface area of marble chips.

Sodium Thiosulphate and Hydrochloric acid reaction (‘disappearing cross’)

Client: Chemical engineers wishing to check if turbidity is a useful surrogate measurement for whether a reaction has reached completion.

How does the reaction respond to changes in acid concentration (it is first order for thiosulphate concentration but varies from first to zero order with acid).

How can we assess the amount of oil contamination on beaches?

Client: Various groups will want to assess oil contamination, and a simple quick method would be appreciated.

The method used solvent extraction. Sand samples were laced with oil and the efficiency of recovery was measured. The sensitivity of the method was also estimated.

Synthesis and isolation of propanoic acid from propan-1-ol.

Client: Chemical suppliers who want to investigate production of this chemical.

Trialling different methods.

Making biodiesel from waste vegetable oil.

Client: Motoring enthusiasts who want to make their own environmentally-friendly and cheap fuel.

Using methanol and sodium hydroxide it is possible to make diesel fuel from old chip fat.

Analysing the gases remaining after burning a candle in a gas jar.

Client: Motor vehicle engineers who want to check the composition of exhaust gases.

CO₂ is easy; it is readily absorbed with NaOH.

O₂ is harder; an oxygen probe is very useful but otherwise oxygen could be absorbed by, for example, the slow reaction of steel wool.

CO is challenging; it will be absorbed by CuCl solution but it is in very low concentrations.

Extraction of caffeine from tea.

Client: Suppliers or independent analysts who want to assess the caffeine content of tea products. Chemical suppliers who want to provide pure caffeine to clients.

 This method usually involves solvent extraction with a chlorinated alkane (e.g. dichloromethane or 1,1,1,-trichloroethane). With care it is possible to recycle the solvent and avoid health and environmental damage.

Other suggestions

• Investigation of weak acid strengths/synthesis of new acids
• Rate expression for tin/iodine reaction – kinetics of a reaction
• Nobili’s rings – strange colours seen during electrolysis.
• A transient red colour – the chemistry of iron/sulphate complexes.
• Liesegang rings – stripey effects in gels.
• Polarimetry to investigate concentrations of sugars. Client: Suppliers of sugar syrups who want to assess their products.
• Flame photometry to determine concentrations of aqueous ions. Client: Analysis of mineral water samples to check manufacturers' claims.
• Is there a connection between aluminium and Alzheimer's disease?
• Is the level of chloramines found in swimming pool water affected by temperature? Client: Swimming pool operators concerned about eye irritation amongst their customers.
• Effectiveness of two major washing powders on five common household stains. Client: Consumer testing organisation who wants to test commercial claims.
• Factors affecting the decomposition of biodegradable plastics. Client: Environmental agencies testing claims of environmental-friendliness from plastics manufacturers.
• Studies of infrared spectroscopy: nature and applications. Client: Applications include breath-testing for alcohol and testing vehicle exhaust emissions.
• NaCl and potential alternatives to NaCl as a roadway de-icer. Client: Highways agency investigating de-icers which cause less environmental damage - but at what cost?
• Synthesis and analysis of hexane-3,4-diol.
• Calcium carbonate content of seashells.
• Characterisation of New Polyethylenes Prepared by Single-Site Catalysis.
• An Investigation Into The Uses Of Environmentally Friendly Additives/Alternatives To Petrol.
• Protein Purification.
• Water Pollution in Hong Kong.
• A study into the colour of ketchup.
• An investigation into the effects of heat, pH and long term UV radiation on sunscreens.
• Comparison By Spectral Characterisation Of Myoglobin In Beef, Pork and Turkey.
• Spectrophotometric Determination of Trace Amounts of Iron in Plant Samples.
• The effect of disulphide reduction on the structure, and activity of Yeast Alcohol Dehydrogenase.
• Investigation into the effect of pH on the mechanism of glycation of phenylalanine as a model of the glycation of the B chain of insulin.
• Analysis of Vitamin C in Orange Juice through a Chemiluminescent Clock Reaction.
• Investigating the Effect of Different Halide Ions on the Stem Volmer Constant.
• Developing and Validating an Assay for Tissue Thiols and the Analysis of the Effects of Aging and Taurine on Tissue Thiols.
• Relation between the Slow Relaxation Time and Foaming of Selected ICI Surfactants.
• Purification of ibuprofen from commercial tablets.
• Building a breathalyser.
• Titration of various commercial vinegar samples.
• Titration of vitamin C content of commercial fruit juices.
• Investigation in the synthesis of acetylsalicylic acid (aspirin).

Physics

Shear-thickening fluids

Client: Manufacturers of military flak jackets are investigating if jackets can be made flexible at low strain but rigid at high strain by incorporating shear-thickening fluids.

Corn starch mixed with water has bizarre properties - under low strain it behaves as a liquid but if hit with a hammer it solidifies and shatters. What composition achieves the best transition from fluid to solid? What force is required to achieve the transition?

Mpemba effect

Client: Ice-cream manufacturers who want to reduce time by freezing their product from warm samples instead of cooling to room temperature before freezing.

Strangely, under the right conditions, warm water will freeze faster than cooler water. Various reasons for this have been proposed, but it is still a prime example of an experiment that defies intuition.

Challenges: Research the literature on the phenomenon. Establish conditions under which the effect is observed. Monitor the experiment closely to discover what causes the effect. Use the information discovered to design a change the conditions so that the effect is no longer observed.

Studying the impact of air rifle pellets in gelatin.

Client: Forensic laboratories investigating wounding incidents. Air rifle manufacturers concerned about safety.

The student made ballistic-concentration gelatin and assessed the velocity of the air rifle pellet and its subsequent penetration into the gelatin target.

Making a vee-notch flowmeter from a plastic milk bottle and calibrating it.

Client: People who might require a cheap method to assess flow rates of running water e.g. environmental surveyors, central heating engineers.

This is a very simple experiment, but challenging to do well. The student will need to measure the water level exactly as well as measuring the flow rate by collecting water over a measured period of time.

Biology

Thermal death point of cell membranes.

Client: Farmers who would like to predict which crops would fare better in conditions of increased summer temperatures.

Using a colorimeter, it is easy to assess damage to the cell membranes of beetroot samples by the amount of pigment they release to the medium. This correlates to the temperature at which the beetroot is incubated. Red cabbage seems to require a higher temperature which may reflect the mediterranean origins of brassicas. Non-pigments plants could be assessed by measuring the amount of protein/salts/carbohydrate/etc they release.

Peroxidase activity.

Client: Health food suppliers who wish to promote the anti-oxidant properties of various foods.

The peroxidase activity of various organisms can be assessed by measuring the rate of oxygen production (either collecting the gas and measuring its volume, timing how long an enzyme-impregnated circle of paper takes to rise to the surface, or datalogging the decrease in mass of the sample as gas is released). Organisms compared could be: animal/fungus/plant or different varieties of pepper. The effect of temperature or other conditions on the enzyme could also be studied. Lead cations and nitrate anions are both inhibitors, although the latter is not well known as an inhibitor.