Monday, 8 October 2012

Energy stored in food

Equipment

Boiling tube
Thermometer
Clamp & stand
Cork and pin
Measuring cylinder (25ml)
Bunsen
Goggles
Top pan balance
Flammable food samples

Method

Set up the clamp and stand to hold the boiling tube a known distance above the cork and pin to ensure the same level of heat flow into the boiling tube with each test.
Measure out 20ml of water and place it in the boiling tube and clamp into place.
Add the thermometer to the tube and note the water temperature.
Find the mass of the food sample you are using, note this down and then place it on the pin.
Light the food sample and then quickly position it under the boiling tube.
Once the food sample has finished burning record the temperature of the water.
Repeat three times for each food sample with fresh water.

Safety

Be careful of all hot materials, such as the pin and boiling tube. If the water temperature has raised significantly collect a fresh boiling tube rather than putting cold water in to a hot tube as it could shatter.

Analysis

Work out the temperature rise and multiply this by 84J per degree to get the energy transferred. Divide this answer by the mass of food sample used to find the energy per gram of food.