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Hole-y Potato

A (w)hole new way to make chips

Australian Curriculum links

  • Science > Physical Sciences > Year 4 > ACSSU076
  • Science > Chemical Sciences > Year 5 > ACSSU077

You’ll need

  • A raw, unpeeled potato
  • Straight plastic drinking straws

Time required

5 minutes

Try this

  1. Place the potato on a table and hold it steady with one hand.
  2. Grasp the middle of a straw firmly without bending or crushing it. Leave the top end of the straw uncovered.
  3. Hold the straw 10cm above the potato and then stab the straw into the potato. Will the straw pierce the potato? Is the straw bent or crushed?
  4. Using a new straw, place your thumb over the top end of the straw to make an air tight seal.
  5. Hold the straw 10cm above the potato. Once again, stab the end of the straw into the potato. Will the straw pierce the potato this time? Is the straw bent or crushed?

What’s happening?

This activity demonstrates the idea that air has ‘push’, or pressure. In the same way that air that has been pumped into a bicycle tyre pushes out on the wall of the tyre, air that is trapped in the straw when one end is covered by a thumb and the other is in contact with the potato pushes on the straw, increasing its structural integrity.