Page 21 - 新思维科学活动用书9 样章

1 Photosynthesis and the carbon cycle

Arun set up four boiling tubes like this:

hydrogencarbonate
indicator
freshwater shrimp

water plant
A B C D

Arun recorded the colour of the indicator in each tube at the start of his experiment. Then he left the

tubes in the laboratory for two hours, and recorded the colour again.

This is what he wrote down.

A red, red B red, yellow

C red, purple D red, red

2 Suggest why Arun put a bung in each tube.

3 Name two variables that Arun kept the same in his experiment.

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