HAEF Athens College
IB Environmental Systems & Societies SL
Getting Energy from Foods – Burning Nuts
Introduction & Environmental Issue
How can we show that a piece of bread, for example contains energy? One way is to burn it. When food is burned
the energy contained inside it is set free as heat.
We can use this to find out how much energy a particular piece of bread contains. We set it on fire, and estimate
how much heat it gives out. A known mass of food is burned. The heat given out heats up a known volume of water.
The energy contained in food can be expressed in kilojoules (kJ). 4.2 kJ of energy are required to raise the
temperature of 1Kg of water by 1oC.
Over the recent years there has been an exponential increase in the human population of the planet. Hence, the
demand for food production has increased. It is important for farmers to identify which plant/crop has more energy
so that they know what to grow. Should this be grown locally or can it be grown remotely and then transported?
What is a more ecological solution? From the nuts tested, which nuts should be preferred for mass production?
Research Question
How much energy is released from nuts, estimated by measuring the change in temperature of 20ml of water?
Materials
Measuring cylinder, test tubes, test tube rack, thermometer, stand, clamp, electronic weighing scale, mounted
needle, lighter, Bunsen burner, walnuts, hazelnuts, peanuts, cashews and pistachio nuts
Method: (BEFORE STARTING MAKE SURE YOU ARE WEARING YOUR LAB COAT AND SAFETY
GOGGLES)
1.
2.
3.
4.
5.
6.
Measure out 20ml of water using the measuring cylinder and place it in a test tube.
Clamp the test tube to a stand and place the thermometer in it.
Record the temperature of the water (initial temperature)
Weigh the walnut and record the mass. The mass should not exceed 0.7 grams.
Fix the nut on the pointed needle.
Ignite the Bunsen burner using the lighter. Remember! Flame first, then gas! Place the nut into the flame
until it ignites.
7. Transfer the nut under the test tube containing the water and hold it in position until the nut stops burning.
8. Measure the temperature of the water (final temperature).
9. Repeat steps 1-8 on more time.
10. Repeat steps 1-9 for the remaining nuts (hazelnut, peanut, cashew, pistachio)
Record your results here:
Mass (grams)
Type of Nut
Trial 1
Trial 2
Initial Temperature (oC)
Trial 1
Trial 2
Final Temperature (oC)
Trial 1
Trial 2