Page 7 - 新思维科学活动用书9 样章

1 Photosynthesis and the carbon cycle

Exercise 1.1B The effect of different colours of light on the
rate of photosynthesis

Practice

This exercise gives you practice in recording results, and also thinking about variables in an
experiment.

Marcus wanted to find out which colour of light would make a plant photosynthesise fastest.

The diagram shows the apparatus that he set up.

red cellophane blue cellophane

water water

test tube test tube

water plant water plant

green cellophane colourless cellophane

water water

test tube test tube

water plant water plant

Marcus shone a light onto each tube. He counted the number of bubbles that the water plant gave off
in one minute. He did this three times for each water plant.

These are his results.

red: 10, 12, 11 blue: 8, 12, 10

green: 4, 5, 6 colourless: 11, 13, 12

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