Name:
Date:
Does water evaporate?
You will need:
What you need to do:
2 fresh tulips, 2 narrow-necked bottles,
water, cooking oil, Vaseline and a felt-tip
pen
• Fill both bottles with water.
• Grease the underside of the leaves of one
tulip with Vaseline.
• Now put one tulip in a bottle full of water and
pour a little cooking oil on the surface.
Start:
• Finally, mark the water level on the bottle.
Which bottle will empty
faster?
End:
Observation:
The water level only drops in
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the bottle containing the tulip
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not treated with Vaseline.
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Why is that?
The pores are located on the underside of the leaf. The Vaseline
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has blocked the pores and prevented transpiration.
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Worksheet 7/3 – Plant growth – Water as a regulator – Does water evaporate? / Solution ©