Calculating energy intake and energy needs
What the activity is for
To establish that energy can be measured in joules and that having available too few joules to shift limits what one can do.
What to prepare
- a collection of food labels, showing energy per 100 g marked in joules, or a nutrition data table showing energy per 100 g only
- a diary of a day's activity for the pupil, showing the number of minutes spent on each activity for one 24-hour period
What happens during this activity
This activity could usefully be carried out with spreadsheets, using technology to help keep track of the calculations.
Get each pupil to think about their energy needs first by getting each one to identify their different periods of activity during the 24-hour period, and then mapping theses according to the following categories.
|activity||energy for each minute / kilojoule|
|walking moderately quickly||21|
|walking up and down stairs||38|
Pupils should choose one of these for each period of activity, choosing the activity that they think most closely matches their actions. Then they can now calculate their energy demand for the day.
Next the pupils should map out their food intake for the 24-hour period and use the food labels to work out their total energy input during this time. Do their energy input and output figures indicate a balance?
With their energy balance figures at hand, it is interesting to discuss the effects of going into an energy surplus or deficit over the longer and shorter term.