Bronze Awards are typically completed by students aged 11+. They complete a ten-hour project which is a perfect introduction to STEM project work. Over the course of the project, teams of students design their own investigation, record their findings, and reflect on their learnings. This process gives students a taste of what it is like to be a scientist or engineer in the real-world.
Silver Awards are typically completed by students aged 14+ over thirty hours. Project work at Silver level is designed to stretch your students and enrich their STEM studies. Students direct the project, determining the project’s aim and how they will achieve it. They carry out the project, record and analyse their results and reflect on the project and their learnings. All Silver projects are assessed by CREST assessors via our online platform.
Gold Awards are typically completed by students aged 16+ over seventy hours. Students’ projects are self-directed, longer term and immerse them in real research. At this level, we recommend students work with a mentor from their chosen STEM field of study. All Gold projects are assessed by CREST assessors via our online platform. There are more CREST approved resources that have been developed by our partners and providers specific to your region.
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Page 1 of 2 Measuring alcohol levels In much of the UK, it is illegal to drive if the alcohol level in your blood is above 80 mg per 100 ml, about 0.08%. In Scotland, the legal limit is 50 mg of alcohol per 100 ml of blood. We therefore need ways to determine whether a person is ‘over the limit’. The aim of this project is to find out how a suspect’s alcohol level can be measured. You will investigate simple chemical tests, and more sophisticated methods. Getting Started Start with simple aqueous solutions of ethanol, and progress to testing for ethanol dissolved in artificial urine. This project concerns ‘ethanol’, the alcohol present in drinks. However, the ethanol you use for testing has had methanol added. It is toxic and is not drinkable. Qualitative tests: Try out, chemical tests for alcohols, including reduction of dichromate ions. Are any of these specific to ethanol, or do they detect alcohols in general? By progressive dilution, determine the lowest concentration of aqueous ethanol that you can detect. Is it low enough to detect the legal limit? What would be the problems in applying such tests to a driver’s blood or urine sample? You could try testing alcohol dissolved in artificial urine instead of in water. Quantitative tests: Devise, and try out, a method of adapting one of the above tests to measure the concentration of ethanol in an aqueous solution, not just detect it. Colorimetry might help: Again, test whether you could measure concentrations at least down to the legal limits. Click to edit project description Explain whether the method could be used with blood or urine samples. Devise, construct and test an alcohol analyser. This could be a portable breathtester, or a piece of laboratory apparatus, such as a simple gas chromatograph. Initially, aim to distinguish between ‘pass’ and ‘fail’, for example test samples with ethanol levels half and double the legal limit. The next step would be to calibrate your device, and then to measure samples with concentrations known to your teacher, but not to you. Things to think about The reduction of dichromate was used as the basis of the original breath-in-abag ‘Breathalyser’. Find out how it measured, rather than just detected, the ethanol in breath. The dichromate reaction is not specific to ethanol. Why is it reasonable to assume that ethanol is the only alcohol likely to be present in a person’s breath? The legal limit for ethanol in breath is 35 μg per 100ml or 22 μg in Scotland (μg = microgram). Some people claimed that eating pickled onions would beat the Breathalyser - devise a way to test this theory. Useful Resources Local police may be willing to show you their breath alcohol meters. You should also link up with an organisation that uses appropriate instrumental analysis (though not necessarily for ethanol), so that you can see the instruments in use, and maybe analyse some of your own samples. Recipes for artificial urine can be found on the internet. Measuring ethanol concentration in blood or urine is more complex than in an aqueous solution. It needs a quantitative method that is specific to ethanol and unaffected by other substances in the mixture. Miniaturisation and electronics have allowed some laboratory techniques to be incorporated into portable alcohol meters. These are used not only by police, but also in the rail and airline industries and other workplaces. If you have made external links, why not use these to investigate these methods?