Atmospheric Pressure
Properties of Matter

Blowing Bags

At home for 5-11 11-14

What you need

  • Plastic bin bag


  1. Hold the bin bag about 5 cm away from your mouth. Make sure it's not any closer!
  2. With your thumb and forefinger create a circle to place the entrance to the bag on.
  3. Gently blow into the bag. The bag will inflate quickly!

Results and Explanation

When you blow directly into the bag, the only air flowing into the bag is from your lungs. When you blow from a short distance away you create an air flow that also takes in the surrounding air, which is used to inflate the bag.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

Atmospheric Pressure
is a special case of Pressure

Matter and Nuclear CPD videos

Our new set of videos gives teachers and coaches of physics a preview of the training we offer ahead of this term's live support sessions.

Learn more