Which Shape Makes The Best Leaf?

construction paper
water gun


Cut these four shapes out of paper:
a rectangle
a circle
a smooth-edged leaf shape
a tooth-edged leaf shape

Tape a straw onto each shape. Use the water gun to squirt water down the straw. How does the water flow over each surface? Which ones do you think are most effective at draining the water? Why do you think real leaves are shaped the way they are?

Explanation: The natural leaf shapes help to direct water down the surface of the leaf and gather at the tip, where it will eventually drip right off the leaf. In a rainstorm, this helps to ensure that plants aren't torn to pieces by the weight of the water on their leaves.

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