The Pressure Fountain

Materials Needed:

  • One empty bottle (without the bottle cap)
  • One straw
  • Plasticine
  • One balloon


Optional Materials to Decorate:

  • Cellophane
  • Construction Paper
  • Cotton Balls
  • Tape or Glue

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  1. Drill or poke a small hole half way up on one side of the bottle
  2. Put the straw into the hole and seal the hole tightly with plasticine
  3. Fill the bottle with some water from the top
  4. Prepare a bowl to catch the water (or do it over a sink or outside)
  5. Blow up a balloon and pinch the neck of the balloon
  6. Carefully put the balloon over the bottles cap area
  7. Watch the air in the balloon push the water out, creating your very own fountain!


How Does it Work?

Pressure is created when air is trapped inside of the balloon. The air which is forced into a confined space wants to escape. By releasing the air from the balloon into the bottle, water is forced out through the straw, creating a fountain. Eventually, when all of the water is displaced from the bottle, the remaining air from the balloon is still wanting to escape which is why air continues to come out of the straw, as it is the only outlet for the trapped air.