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How Plants Feed
Reference chapter
Question 1
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The following experiment was set up to investigate how a pondweed breathes in the light and in the dark.
Note: The carbon dioxide indicator is a coloured liquid which does not harm the plant. It can have three colours:
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Purple or violet = No carbon dioxide
Red = A little carbon dioxide
Yellow = A lot of carbon dioxide |
At the beginning of the experiment the carbon dioxide indicator was red. All three tubes were left in the light for a
few hours. Then the colour of the indicator liquid was recorded.
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1. Why was the aluminium foil wrapped around tube B? |
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2. Why were the tubes filled to the top with liquid and stoppered with rubber bungs? |
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3. Tube C had no plant in it, just indicator liquid. Why was it important to
include this tube in the experiment? |
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4. Colour the tubes in the diagram opposite in the colours you think they should have after a few hours.
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5. What does this experiment tell you about the way green plants, such as the
pondweed, exchange gases in the light and in the dark? |
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© Paul Billiet & Shirley Burchill 2009 |
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