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Friday 11 March 2016

FIRE

 WARNING: FIRE RISK

The first brainstorm question of the day 'What is fire?' actually had a few scratching their heads but when discussing it with their group some ideas began to flow. 'What makes fire?' gathered a lot more background knowledge to build on.



We then discussed how scientist use models to show things because we can't actually 'see' them and as we are scientists we needed to make some models of atoms and molecules to understand what happens to create fire and the chemical change that occurs. This was the fun part. I used methane gas (CH4) as a fuel source as it burns cleanly and produces just water (H2O) and carbon dioxide (CO2) and many students were familiar with this gas as it was used for cooking at home. The students made the methane gas molecule first, looking closely at the structure.



Next they had to think about what fire needs to burn so oxygen (O2) needed to be built.


Funnily enough no one was keen to set fire to their lollies for the demonstration so we mimed the ignition but had to make a quick rearrangement of the molecules to demonstrate what happens to the gas and oxygen. As everyone had selected different colours they had to think carefully about which were the Hydrogen and which were the Oxygen molecules when restructuring into Carbon dioxide and Water.


Some students took up the challenge of attempting to create the molecules without a picture and they did an excellent job without knowing the exact structure while others preferred to follow a diagram. Everyone was successful in creating jube lollipops and the challenge was set to see how many they could cram onto one toothpick!





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