Year 5 Science Changes of Materials – Block 5PCM – Changing Materials Education Pack

Session 3:The Chemistry of Cooking: mixing, heating and burning
Science curriculum area: Changes of Materials / i. explain that some changes result in the formation of new materials, and that this kind of change is not usually reversible, including changes associated with burning and the action of acid on bicarbonate of soda
Working Scientifically (UKS2) / i. planning different types of scientific enquiries to answer questions, including recognising and controlling variables where necessary
ii. recording results of increasing complexity using scientific diagrams and labels
iii. taking measurements, using a range of scientific equipment, with increasing accuracy and precision, taking repeat readings when appropriate
iv. using test results to make predictions to set up further comparative and fair tests
v. reporting and presenting findings from enquiries, including conclusions, causal relationships and explanations of and degree of trust in results, in written forms
Teaching Objectives /
  • To plan and carry out irreversible cooking investigations that may create some new materials
  • To record and present methods, findings and further investigations in written form

Other curriculum areas / Computing
  • understand the opportunities that the www offers for communication and collaboration; select, use & combine software (including Internet services) to design & create content

Teaching Objectives /
  • To create a webpage with embedded video and pin to Pinterest board

Key Vocabulary:variables, accuracy, precision, enquiry, new material, not usually reversible, gas given off, degree of trust
ResourcesBaked goods ingredients list/images, yeast, sugar, baking powder, vinegar, 1L plastic bottle, balloons, bread and cake ingredients, jelly, eggs & access to cooking facilities, access to the Internet, video recording devices / Weblinks
- Blow up a balloon with yeast, Science Bob
Whole Class:Prep all experiment, baking and cooking materials and ensure you have access to an oven and hob. You may need an extra adult to help out during this session.Have the ingredients of various ‘bakes’ on each table and ask chn if they can guess what each makes when mixed together and baked –chnmove around the room and try to match all of the ‘bakes’ to their ingredients (use images and lists provided, or you could use real ingredients, and if you like baking, you could bring in real examples to sample!). Check the ingredient matches and ask chn if theythink they can turn the end product back into the ingredients? No! These are irreversible changes – explain that that is what cooking is all about and that today’s section of the education pack is all about irreversible baking and cooking in the kitchen. Explain though that chn will be approaching the cooking/baking from a scientific slant and will still need to come up with enquiry questions, predictions, record results and present findings. Using the guidance (see resources) discuss the various ‘recipe investigations’. Look at each one in turn together and identify enquiry questions by explaining that they need to investigate something that may affect the end product (see examples given). Demonstrate the science of a yeast and sugar reaction (see link for instructions and make sure that you do a control without sugar – this is important for later on!) and repeat with baking powder and vinegar. Can the chn identify that both reactions are giving off a new product in the form of a gas? Having discussed the science behind the two bakes send chn off to complete their baking/cooking challenge.
Activities:Encourage chn to approach their cooking/baking scientifically, using the sticky-note approach (see session 1 resources). Help them to predict what will happen and why; and whether it will be reversible or not. Provide chn with the guidance and recipes and encourage them to complete independently. In gps with an adult complete the ‘cook an egg’ investigation (see enquiry questions) and do a poll with each gp to find out which cooked eggs are the most popular. Ask chn what they think will happen to the eggs depending on how you cook them? (Poached, fried, boiled, scrambled) Ask chn if they are still eggs – can we turn them back into their raw state? As part of this investigation make toastto accompany the eggs, and try to burn it! Do the chn want the burnt toast? Why not?! Explain that a new product has been made – carbon (with other bits). Explain that burnt bits are not good for us because of the chemical changes that have occurred so we don’t eat burnt things – they don’t taste nice anyway!Do a video for the egg investigation part of the education pack, to embed on their webpages. Get chn to write up their investigations, encouraging them to include diagrams of the yeast and baking powder bottle experiments to explain the science behind the cooking.
Plenary / Get chn to share their findings – they will likely tell you that the bread investigation didn’t work! The sugarless rolls will still have risen. See if chn can suggest why (yeast can convert the starch in flour into sugars – it can take a bit longer, but yeast will still ferment even without granular sugar as an ingredient because it gets sugars from other ingredients). Explain that as scientists it is always important to ask ‘why’ when something unexpected happens! Ask chn in general why they think we cook food.It makes the food taste better and become more digestible. Also many foods would make us ill if eaten raw – why? Talk about how bacteria are killed when things are cooked (meat and vegetables – remind chn of the importance of washing raw veg as it can carry e-coli). Share chn’s further enquiry questions and look at the ways in which the investigations have been written up.Homework: encourage chn to cook and bake at home and to think about the science behind what they make.
Outcomes / Children will
  • Cook and bake noting the irreversible changes that occur
  • Plan and carry out investigations into the impact of certain ingredients on an end product
  • Create aninvestigation webpage, with an embedded videoandpin it toa Pinterest board

© Original resource copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users.

We refer you to our warning, at the foot of the block overview, about links to other websites.