Efficiency
Energy and Thermal Physics
Human energy, food and exercise
Practical Activity
for 14-16
Class practical
Considering the energy stored in foodstuffs and the energy demanded by human activity.
Apparatus and Materials
Data in the tables below.
Health & Safety and Technical Notes
Read our standard health & safety guidance
Procedure
- You should display or provide the data from table A: energy stored in food. Information given on the packet tells you the energy stored in different foods. Students can be asked to compare the energy stored in different foodstuffs.
- Display or provide the data from the next two tables, Table B (human energy demands) and Table C (data for a coal miner). The miner was 32 years old, 1.75 m tall and had a mass of 67 kg.
Table A: Energy stored in food
| Food | Energy value (kcal /100g) | Energy value (kJ /100g) |
|---|---|---|
| butter | 499 | 2,087 |
| sugar | 389 | 1,627 |
| white bread | 266 | 1,112 |
| margarine | 620 | 2,590 |
| potato, baked | 89 | 372 |
| MacDonald's hash browns | 257 | 1,075 |
| hamburger (no cheese) | 275 | 1,150 |
| fried fish | 221 | 924 |
| oranges, raw | 47 | 196 |
| lentils, boiled | 116 | 485 |
| carrots, raw | 41 | 171 |
| eggs, fried | 201 | 840 |
| cheese pizza 14" | 257 | 1,075 |
| hocolate chip cookies, low fat | 453 | 1,895 |
| cola carbonated drink | 37 | 154 |
| corn flakes, breakfast cereal | 360 | 1,506 |
Table B: Human energy demands
| Person | Energy required (kJ/day) | |
|---|---|---|
| Child (either sex) | ||
| 0 to 1 yr | 4,185 | |
| 2 to 6 yr | 6,278 | |
| 7 to 10 yr | 8,370 | |
| Teenager | Males | Females |
| 11 to 14 yr | 11,500 | 11,500 |
| 15 to 19 yr | 14,650 | 10,460 |
| Adult (20 yrs and over) | ||
| lying in bed | 7,324 | 6,278 |
| light work | 11,500 | 9,420 |
| heavy work | 14,650 | 12,550 |
| extremely heavy work | 20,925 |
Table B: Data for a coal miner
| Activity | Energy needed (kJ/minute) |
|---|---|
| resting in bed | 3.9 |
| washing, shaving, dressing | 13.8 |
| walking | 20.5 |
| standing | 7.5 |
| cycling | 27.6 |
| digging coal | 28.0 |
| shovelling coal | 26.9 |
| walking (in coal mine) | 28.0 |
Teaching Notes
- From Table A, you might ask students to calculate the energy stored in a recent day's food. They will need to know the approximate mass of a normal serving.
- From Table B you might ask students how much energy they need each 24 hours. The answer depends very much on the sort of person, particularly age and occupation. Table C gives some data for a very physical job.
- The data in these tables could be displayed by a data projector, issued as worksheets, or prepared as wall charts to be left in the classroom or laboratory.
This experiment was safety-tested in January 2006
