Energy in food
We burned some different types of food and estimated how much stored energy was released from each one as heat. To measure this, we used a calorimeter - a device to measure heat changes arising from chemical reactions or physical changes. The home-made calorimeters helped to shield the burning food from draughts, while directing most of the heat produced towards a small can of water.
We used a new batch of water at room temperature for each experiment, keeping the volume of water constant. We measured the starting temperature, weighed the mass of food to be burned, lit the food, placed it in the calorimeter, and when it had burned out, we measured the final temperature of the water and calculated the rise. The older children calculated how much energy was captured by the calorimeter per gram of food burned.
We looked at the nutrition information on some of the food packets and discussed the meanings of the terms ‘calorie’ and 'kilocalorie’, and discussed how the information on the packet might be misleading - for instance, if it is presented as calories per portion, rather than per 100g.
I found these websites helpful when preparing:
