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Is food a good fuel?
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Is food a good fuel?
Suitable for: 11–14 years
Curriculum and learning links:
Food, fuels, respiration, energy changes
Learning objectives:
• Experimentally prove which food type has the most energy stored within it.
• Evaluate the effectiveness of different fuels.
Activities:
Opening activity
• Show Clip 17
• Explain to the class that they will now investigate the amount of energy stored in different
foods and use this information to work out what makes a good fuel.
Development activities
Energy in Foods
• Check that no students have allergies to the food
types you intend to use.
• Show students examples of the information panels on
food packaging, drawing their attention to the energy
section (for example, a typical packet of crisps has
about 550kJ in it). Discuss what foods they think
contain the most energy and why.
• Ask students to set up the equipment as shown in the
photograph by securing their boiling tube to a clamp stand.
• Ask students to burn the different foods you have
provided in turn and record the change in
temperature of the water. The water should be
replaced after each attempt. If students find it hard to
hold the food on a mounted needle, they should
burn it on a teaspoon.
• Ask the students to work out which food contains the most
energy by looking at how much the temperature of the water changed in each test.
Good Fuels
This activity could be completed as a teacher demonstration or a student practical.
• As a class, draw up a list of criteria that make something a ‘good fuel’ – for example,
something that is easy to store, light, that is cheap, readily available, that produces
little or no smoke, gives a hot flame, burns for a long time.
• Burn the different fuels you have provided in turn in a metal dish on a heatproof mat.
• Encourage students to make observations against the criteria you identified.
© BBC
Is food a good fuel?
Reflect and review
• Summarise the class’s results for the Energy in Foods experiment.
• Ask students how they could improve the experiment by identifying errors – for example, the
variable distance between the food and the test tube.
• Ask students to write up this experiment and recommend one food that could be used in a
rocket-powered bike.
• Summarise the class results for the Good Fuels experiment and discuss whether they agree
with the students’ initial thoughts or not.
• To finish, show Clip 18 and discuss with students why safety is very important when
carrying out experiments.
Want to explore further?
• The Energy in Foods experiment can be extended by asking students to calculate the
joules of energy in each food. To do this, they will need to use the equation:
q = m x c x ΔT
where q is the heat energy (J), m is the mass of the food (g), c is the specific heat
capacity of water (4.18J/g/oC) and ΔT is the change in temperature (oC).
• The Good Fuels experiment could be extended by asking the students to discuss
‘green’ fuels such as biodiesel and hydrogen and what their merits are.
You will need
• Clip 17 (4’31”)
• Clip 18 (1’07”)
• Clamps and stands
• Boiling tubes
• Food packaging
• Variety of foods (e.g. crisps,
dried pasta, popcorn, peanuts)
• Thermometers
• Heatproof mats
• Variety of fuels for burning (e.g. coal,
firelighters, ethanol, wood chippings)
• Metal dishes
• Mounted needles
Or:
Teaspoons
Technician’s notes
• Temperature probes linked to data-logging equipment could be used for
the Energy in Foods experiment.
Health and safety
ly for both activities (including eye
• Normal laboratory guidelines app
protection).
allergies are taken into account
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• Please ensure
when preparing this lesson.
of the foods in the lab.
• Students must be told not to eat any
pleted over a heatproof mat.
• Both experiments should be com
these experiments at home.
• Students must be told not to repeat
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• If burning ethanol, special care mu
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© BBC
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