7. Food Energy Values

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7. Food Energy Values

• Scientific Enquiry Question

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• Part of Roys experiment is to burn a piece of
• crispbread.
• (a). How has Roy arranged his apparatus so he
  works safely? _________________________
• ____________________________________
• ____________________________________

Hot pin held securely / clamp secure / test-tube
pointing away from him / stable on bench / in
the centre of the bench. (Goggles not acceptable)
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• (b). Look carefully at the experiment and THINK !
• (i) What do you think he is trying to find out?
• ______________________________________
• (ii) What is his key independent variable?
• ______________________________________
• (iii) When should he record the temperature of
  the water?
• ______________________________________

How much energy in the food is transferred to the
water.
The type of food being burned / the energy
content of the food.
The start and final temperature.
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• Roy wants to compare potato crisps and the
  crispbread. So, he does the experiment again
  using a piece of potato crisp. Suggest three
  things he must do to make the experiment a fair
  test.
• 1. ___________________________________
• 2. ___________________________________
• 3. ___________________________________

Same mass of food.
Same set up of equipment e.g. distance of flame
to tube.
Same volume of water.
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• (d). The table shows some of the nutritional
  energy values for crispbread and potato crisps.

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• (i). Roy burns 1.0 g of potato crisp instead of
  1.0 g of crispbread in a similar experiment.
  What result will he get when he burns the potato
  crisp? Tick the correct box.
• The change in the temperature of the water
• will be the same.
• The change in the temperature of the water
• will be smaller.
• The change in the temperature of the water
• will be greater.
• There will be no change in the temperature
• of the water.

v
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• (ii). The carbohydrate values are identical.
  Starch is a type of carbohydrate. It probably
  makes up most of the 60 grams.
• What other type of carbohydrate makes up the
  rest of the amount? _____________________
• (iii). Iodine solution can be used to test foods
  for starch.
• What colour is iodine solution? ____________
• What colour does it turn if the food contains
  starch? _______________________________

Sugar
Yellow/orange
Blue/black
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• (e). How many times more fat is there in potato
  crisps than crispbread
• ______________________________________
• (f). Explain why eating too many potato crisps is
  not a good idea.
• ______________________________________
• ______________________________________
• ______________________________________

x 4 more
Unbalanced diet / diet too high in fat / body fat