Rising water experiment

Rising water experiment

Rising water experiment

Follow FizzicsEd 150 Science Experiments:

  • A bowl
  • A candle
  • A clear glass cup that is taller than the candle 
  • Water
  • Playdough 
  • Matched
  • Adult supervision
Matches, a candle, play dough, a water bottle a glass and a plate on a desk
1

Using the playdough, fix the candle to the bowl so that it sits upright inside the bowl.

2

Pour some water into the bowl.

3

With the matches, light the candle.

4

Cover the candle with the glass cup. Watch happens! If you want, you can add food colouring into the water to make the experiment more visible.

What is happening?

You created an area of low pressure!

The water rose into the cup because as the candle burns, it consumes oxygen and in doing so it reduces the pressure inside the cup. This created a pressure difference between the air inside the cup and air outside the cup. This pressure difference caused the high-pressure air outside the cup to push the water down into the plate… allowing the water to be pushed upwards into the inside of the cup towards the lower pressure air.

Variables to test

More on variable here

  • hot vs. cold water
  • Two candles vs. one candle
  • What happens when you use different liquids?

Learn more!

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