Can you continue the multiple choice

questions you were writing yesterday? (Pages 14 and 15)

Do now!

Last lesson

• Absorption of food by the blood

Read pages 14 and 15 and write 10 multiple choice questions (each

with 4 possible answers) to go with

these pages

Today’s lesson

• Measuring the energy content of food

Energy requirements?

Energy requirements?• Vary with age, activity levels and pregnancy

Energy content of foods?

• Burn food

• Measure temperature rise of a known mass of water

• Calculate energy released by burning food (using the specific heat capacity of water)

Let’s do it!

• Measure 10cm3 of water into a test tube• Take temperature of water• Weigh the food• Set light to food and hold it under the test tube• Record final (highest) temperature of water• Record your measurements• Calculate the energy released = 41.9 x temp rise

Energy in foodsType of snack Mass of

snack (g)

Starting temp (°C)

Finish temp (°C)

Temp rise (°C)

Energy produced (J)(41.9 x temp change)

Energy per gram (J/g)

(Energy divided by mass)

Pork rinds

Cheetos

Raisins

Pasta