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What’s in a Bottle?

In this activity, students will investigate a property of air – that it takes up space.

We are constantly surrounded by lots of tiny and invisible air particles. We often think of air as being something light and weightless. In reality, air is a gas that takes up space and has mass (weight). Since there is a lot of “empty” space between air molecules, air can be compressed to fit in a smaller volume.

Air not only has mass, but exerts pressure as well. The particles of air push in all directions and the force that is exerted is called air pressure.

The bottle in the activity is already full of air. In order for more air, or the ball, to move into the bottle, some air has to come out. The air coming out of the bottle pushes the ball with it.

This is a recommended pre-visit activity to Science World.


  • Describe the physical properties of air.


  • Per Demo:
    ball made from scrunched up paper or aluminum foil (it needs to be much smaller than the bottle opening

Key Questions

  • Why won't the ball go into the bottle?
  • Is the bottle empty?

What To Do

  1. Place the bottle on a table so it is horizontal.
  2. Put the ball just inside the mouth of the bottle.
  3. Challenge your volunteer to blow the ball into the bottle.
  4. The ball will fly back toward the volunteer!

Teacher Tip: Up the fun factor by making this a race between two students (with a bottle each and a pile of paper balls), the goal is to get as many balls in as possible (little do they know they won’t get one in!)