7. Food Energy Values

Scientific Enquiry Question

Part of Roy’s experiment is to burn a piece of

crispbread.

(a). How has Roy arranged his apparatus so he works safely? _________________________

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(b). Look carefully at the experiment and THINK !

(i) What do you think he is trying to find out?

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(ii) What is his key independent variable?

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(iii) When should he record the temperature of the water?

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(c) 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. ___________________________________

(d). The table shows some of the nutritional energy values for crispbread and potato crisps.

Food (100g)

Energy Carbohydrate Fat

Crispbread

Potato

Crisps

1450 kJ

2070 kJ

60 g

60 g

7 g

28 g

(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.

(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? _______________________________

(e). How many times more fat is there in potato crisps than crispbread

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(f). Explain why eating too many potato crisps is not a good idea.

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