Energy for living beings – Foody fuels, part 1.
Where do we and all living beings get the energy to survive
and do things?
RESOURCES REQUIRED
- 1 each of packaged food examples – bottle of vegetable oil,
packet of peanuts, bag of sugar, bottle of vodka/gin (think about emptying
or replacing contents with water!)
- Label for bottle of alcohol as most don’t display the energy
content.
1L vodka = 2.2kcalories, 9240kJ
1L gin = 6.8kcalories, 28560kJ
- Sufficient copies of Food frenzy?
DATASHEET for everyone to work from.
TIME REQUIRED
Class time
Approximately one period
OVERVIEW
This has been designed as part of a three lesson topic highlighting some
of the connections between food and bio-fuels (Foody fuels – parts
1, 2 and 3). It can, however, be taught independently of the other two
lessons.
TEACHING ACTIVITIES
Introduction
Lead a discussion, using the following questions, prompts and clarifications:
- “Why do living beings – like you – need energy?”
To stay alive, in human beings’ case, to stay warm, move around,
digest, sense, think etc.
- “Where do you get your energy from?” Explain that although
activity and sleep are essential for health, neither supplies us with
the chemical energy that food does. If your class has previous knowledge
of fuels as concentrated, stored energy, offer a comparison –
“Like fuel, food contains stored energy that we can use when needed.”
- “Which foods make you feel really active and full of energy
just after eating them? Which foods do you most want to eat when you’re
tired or after you’ve one a lot of physical exercise? Which other
foods do you think contain a lot of energy?” Carbohydrates and
fats come under the heading of ‘energy foods’ and are part
of a balanced diet.
- “Where does the energy in food come from?” Trace the basic
energy route back to the sun. Focus on the fact that plants need sunlight,
and that they do the essential work of transforming that light energy
into an energy resource which animals, including us humans, can eat.
“Imagine trying to eat sunlight!”
Learning about the joule.
- Explain that the joule is the basic unit for measuring energy. You
might want to explain that the ‘calories’, which many students
will have heard of, are old-fashioned energy units, now superseded by
the joule in science.
- Use lifting an apple by 1 meter to give pupils a general sense of
the ‘scale’ of a joule.
- Give out some examples of ‘energy foods’ with their energy
ratings in joules written on the packet. The examples listed in the
resources required section above are chosen due to their dual use as
foods and bio-fuels, a link which can be drawn on in Foody fuels - parts
2 and 3.
- Have each pupil work out how far they could lift an apple using the
energy from 100ml or 100g of one of the food examples.
- Hand out copies of the “Food frenzy? DATASHEET” as the
basis for a chart drawing exercise, looking at per capita joule/calorie
consumption in Bangladesh, the UK and the USA.
Food chains
- Draw on pupils’ existing knowledge of food chains. Get the
class to help you draw a food chain, starting with the sun and incorporating
arrows to show the direction of energy flowing through the system.
- Have each pupil draw a food chain, with energy arrows from the sun
to themselves, including a food from their previous nights’ meal.
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