creativeminds Investigate! Snack Attack Recent medical research claims that too much salt is bad for your health. You have a range of snack food and as a health scientist, have to find out which snacks contain the most salt. You have: A variety of salted snacks e.g. crisps, savoury yeast snacks, mini cheese biscuits etc. Hand lenses Filter paper Beakers Filter funnels Water Salt Scales Intel microscope if available Activity 1. If time, search internet to find salt information. 2. Discuss how and why salt is added to snack food (coating on crisps, ingredient in baked snacks). Look at snacks with hand lenses to see salt. Can we measure salt levels this way? 3. How can we extract salt from snacks? Demonstrate salt dissolving in water if necessary. Use filtration to extract salt from snacks. Discuss how to make this a fair test e.g. constant weight/volume, does volume of water added matter? 4. Leave solution in the beakers to evaporate and then weigh beakers against a control to establish salt levels in snacks. This could be evaluated visually. Encourage scientific vocabulary. Explanation The salt in the snacks will dissolve in the water and can be filtered and separated from the snacks. When the water evaporates the amount of salt per mass of cereal can be calculated. The snacks produce more salt if crushed and mixed with warm water. Useful Questions • What is happening to the salt? • How can we get the salt back from the water? • What happens to the water in the beakers, where does it go? • Why does the weight/volume of snacks used matter? • Could we improve this test? • How do we know the crystals produced are salt? creativeminds Investigate! Extension Activities • Plot a graph to compare amount of salt per 100g of product. Does this match the manufacturer's claims? • Repeat test several times to get average salt value. Why should we do this? Compare different brands of the same snack. Research Opportunities • How is salt manufactured? • Are there different types of salt? • How does salt preserve food and why is it necessary to do this? • How does sea life cope with living in a salty environment? Useful Websites www.salt.gov.uk www.walkers.co.uk The Creative Minds project works with museums libraries and archives across the Yorkshire region, to provide young people with learning opportunities in Science, Technology, Engineering & Maths (S.T.E.M.). This ground-breaking project is the first of its kind in the country and is managed by MLA Yorkshire. This pack was developed by Creative Minds and Eureka! The Museum for Children with funding from Yorkshire Forward.