Pressure
Properties of Matter

Straw Water Gun

Enrichment Activity for 5-11 11-14


What you need

  • A drinking straw
  • A friend
  • A ruler
  • Scissors
  • Sticky tape
  • Saucer of water

Instructions

  1. The challenge is to lift the water from the saucer using a straw but without sucking
  2. Get your ruler and cut your drinking straw into two pieces: one 3cm long and one 5cm long
  3. Join the pieces together with sticky tape along one side so they form a 90 degree angle, but leave both ends open
  4. Stand the smaller end of the straw in the saucer of water
  5. Now blow hard!

Results and Explanation

When air moves, its pressure falls. So when you blow, the pressure at the top of the straw drops. But the air over the saucer keeps the same pressure, so the water is pushed up the straw.

ONLINE COMMUNITY FORUM

Have a Physics Teaching Question?

Want to ask it in a safe, friendly, knowledgeable environment? TalkPhysics is an online community for anyone involved in the teaching of pre-19 physics.

Visit TalkPhysics