Weird Science: Make your own airbrush - Hawaii News Now - KGMB and KHNL

Weird Science: Make your own airbrush

HONOLULU (HawaiiNewsNow) - Dr. V is back and he's here to show us how to make our own airbrush using Bernoulli's principle. Try it out!

Dr. V Show: Make your own Airbrush

April 20, 2009

 

Things you need:

  • Straight straw
  • Cup of water
  • Food coloring
  • Scissors
  • Paper

 

The experiment

Please perform this and all experiments under the supervision and with the assistance of an adult. This experiment is one to do outside! Fill your cup of water and mix in at least 15-20 drops food coloring. Stand a piece of paper up next to the cup. Then, cut the straw in half. Hold one half in your mouth and hold or tape the other half in the glass of water so that one inch of the straw is sticking out of the water. Using the straw in your mouth and facing the paper, blow forcefully across the top of the straw in the water. If nothing happens try lowering the straw in the water. You should find that when you blow hard enough you produce a spray of tiny water droplets, just like an airbrush. Try using different colors of water for your airbrush artwork.

 

How does it work?

This experiment demonstrates Bernoulli's principle, which states that rapidly moving air will be at a lower pressure than air that is still. When you blow across the top of the straw, the rapidly moving air is at a lower pressure than the air above the water in your glass. If you blow hard enough, the pressure will be even lower and the air above the glass will push the water all the way up the straw and out of the top. Then the water will enter into the stream of rapidly moving air, from the straw in your mouth, which breaks the water up into tiny droplets which sprays in the direction you are blowing.

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