Cooking, Baking and Boiling!

Year 5 this week have been learning about reversible physical changes (ones that can go back and forth quite freely – for instance ice melting into water and re-freezing) and irreversible chemical changes (ones that go one way as chemical reactions happen to make new substances or products). 

We discussed these sorts of changes in class and examined different reactions we could do in the lab but then turned our attentions to the everyday reactions we take for granted at home. And so, a challenge was set…could Year 5 find some reactions in their home this week? 

The response in class was wonderful with lots of ideas and discussions, but it was when the videos and photos began coming in from Year 5 homes it could have given Jamie Oliver and the British Bake Off Team a run for their money! 

Mrs Hills-Matthews’ inbox this week has been looking very tempting indeed! On Tuesday morning Kiran sent in a photo of a delicious pasta dish and identified this fine Italian creation as a mixture of reversible and irreversible reactions. The pasta cooking and cheese melting were both reversible (if you dried out the pasta after cooking and allowed the water to evaporate and cooled the cheese), but the making of the pasta sauce was irreversible as you could never get the tomatoes back to their uncooked state. Points well made and looking very yummy at that! 

Jayden filmed his kettle boiling with the steam being released and correctly identified this was a reversible reaction where the water vapour gas would condense on a cold surface in the kitchen and then form liquid water again. 

Nora went for a double hit of candle based reactions with the reversible element of wax melting into a liquid and setting (freezing) into a solid after heating but also noted that if the was used as a fuel for the burning candle, then it was an irreversible reaction. To top things off Nora also demonstrated a second irreversible reaction by cooking her very appetising scrambled egg breakfast!  

Etty and Lawrie also took on the challenge with absolute fervour. Etty carefully annotated several reactions she photographed at home including water turning to steam in a pan, making cheese from milk, burning wood and frying mushrooms. Meanwhile, Lawrie boiled water and correctly identified this as reversible, cooked an egg (which he promptly identified as irreversible), lit a candle and watched his cat eat their dinner and commented that all the reactions of digestion were irreversible! What a collection of reactions! 

Roy took his investigations down the confectionary route and had solid pieces of chocolate at room temperature, which were then melted in the microwave – so far so good with the reversible reaction. But then he took the solidifying reversible proof a step further and put the melted chocolate into the freezer for a chilly blast to demonstrate the full reaction. 

However, Bake Off fans with a sweet tooth, would have been even more impressed by the chemical reactions Molly, Aaryan, Kiana and Kiarash produced overnight! Molly baked a whole cake to demonstrate an irreversible reaction of how the cake ingredients combine and then cook into a totally different form. It was proudly brought into school! Aaryan made a batch of ‘Irreversible Reaction Cupcakes’ and created individual home-made banners and toppers for each cake. Kiana and Kiarash joined forces to make a delicious batch of beautifully decorated cupcakes to demonstrate their irrepressible reaction and patisserie skills.  

Outstanding work Year 5 – what an excellent set of reactions identified and thoroughly enjoyed! Very well done indeed!