This collapsing bottle air pressure experiment is also a fun science trick! The bottle collapses without anyone pushing or pulling it.
Adult supervision is needed for this activity, as hot water is used
You’ll need
Hot water – ask an adult to help
A plastic bottle with a lid – different size bottles are good to compare
Oven or heatproof glove
Instructions
Remove the lid from the bottle. Carefully pour hot water into the bottle until it’s about two-thirds full.
Using a heatproof glove, carefully swirl the water around the bottle.
Empty the hot water out of the bottle and quickly replace the lid.
Watch as the bottle collapses in on itself.
Experiment with different sizes and shapes of bottles.
Why does the bottle collapse?
The hot water gives the air inside the bottle energy, allowing the particles to move around more, increasing the pressure inside the bottle. As soon as the hot water is removed from the bottle, the air particles start to cool and lose energy. This reduces the pressure inside the bottle to less than outside the bottle. Air pressing on the outside makes the bottle collapse.
More air pressure experiments for kids
I have six more air pressure experiments you can try, including making water rise into a jar, making a boiled egg drop into a glass and launching a bottle rocket.
Go Science Girls has a fantastic balloon balance activity to demonstrate that air has weight.
Finally, learn about the Bernoulli Principle with a plastic bottle and rolled-up ball of paper.
Last Updated on March 23, 2023 by Emma Vanstone