Efficiency
Energy and Thermal Physics

Human energy, food and exercise

Practical Activity for 14-16 PRACTICAL PHYISCS

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

  1. 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.
  2. 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

FoodEnergy value (kcal /100g)Energy value (kJ /100g)
butter4992,087
sugar3891,627
white bread2661,112
margarine6202,590
potato, baked89372
MacDonald's hash browns2571,075
hamburger (no cheese)2751,150
fried fish221924
oranges, raw47196
lentils, boiled116485
carrots, raw41171
eggs, fried201840
cheese pizza 14"2571,075
hocolate chip cookies, low fat4531,895
cola carbonated drink37154
corn flakes, breakfast cereal3601,506

Table B: Human energy demands

PersonEnergy required (kJ/day)
Child (either sex)
0 to 1 yr4,185
2 to 6 yr6,278
7 to 10 yr8,370
TeenagerMalesFemales
11 to 14 yr11,50011,500
15 to 19 yr14,65010,460
Adult (20 yrs and over)
lying in bed7,3246,278
light work11,5009,420
heavy work14,65012,550
extremely heavy work20,925

Table B: Data for a coal miner

ActivityEnergy needed (kJ/minute)
resting in bed3.9
washing, shaving, dressing13.8
walking20.5
standing7.5
cycling27.6
digging coal28.0
shovelling coal26.9
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

Resources

Download the PDF of the tables.

Efficiency
is used in analyses relating to Engines
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