How Much Energy?
Saturday, 24 August 2013
7:55 PM
How much Energy?
Energy like many other things in life can be measured. When calculating length we use metres (m) and measuring weigh we use grams (g) and when we measure energy we use Joules (J). 
These units are quite small so like we use Kilometres (km) for long distances and kilograms (kg) for heavy weights we use kilojoules (kJ) for large amount of energy.
1- Using the following table can you calculate how much energy you would be taking in if you had an apple, a vegemite sandwich and a strawberry big M for lunch?
Food or Drink
Energy in kJ
Banana
317
Apple
224
Orange
258
Mars bar
1050
Peanut-butter sandwich
1305
Vegemite sandwich
1155
Jam sandwich
870
Apple juice
485
Strawberry Big M
707
Chocolate Big M
1397
2- Using the table create a lunch that you would enjoy. You then need to calculate how much energy you would be taking in by eating that lunch.
3- What form is the energy in when it is in the food, is this energy or potential energy?
4- What happens to the energy that was in the food after we have eaten it?
5- What forms of energy does our body produce?
This energy that we take in in the form of food is used by our bodies to do all sorts of things. The table below shows how much energy it takes to do certain actions; using this information can you answer the following questions?
Action
Energy in kJ
Skip for 5 minutes
285
Swim for 10 minutes
331
Run for 5 minutes
238
Dance for 15 minutes
343
Watch TV 1 hour
351
Cycle for 10 minutes
757
6- How much energy does it take to skip for 15 minutes?
7- How much energy does it take to run for 10 minutes and swim for 20 minutes?
8- How many hours of TV would you have to watch to use up 1000 kJ of energy?
9- How long would you have to dance to use up all the energy in a banana?
10- How long would you have to run to use up all the energy in a marsbar?
11- How long would you have to cycle to use up all the energy you took in from the lunch you decided on in question 2?