Forces and Motion

Bottled Tornado

Enrichment Activity for 5-11 11-14

What you need

  • Two large plastic bottles
  • A washer
  • Water
  • Duct tape
  • Food colouring


  1. Fill one bottle two-thirds full with coloured water Turn the other upside down, put a washer between them and tape the joint firmly
  2. Turn them upside down, let the water flow normally, then swirl the bottles around vigorously

Results and Explanation

When you swirl the water, it forms a vortex like a tornado and flows much faster into the lower bottle.

Air from the lower bottle rushes to the top through a hole in the middle of the vortex as the fast-flowing water drains rapidly at the edges.

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