This is a simple, easy, and fun way to use the physics of air pressure and temperature to crush a bottle! So let’s go ahead and use the force of air pressure in this Collapsing Plastic Bottle Experiment.
Get more fun and easy Atmospheric Pressure Experiments here!
Your kids will love doing this experiment with you and it only takes a few supplies you probably already have around the house!
Collapsing Plastic Bottle Experiment
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- 2-Liter Plastic Bottle
- Hot Water
- Large Casserole Dish
- Ice Water
How to Make a Shrinking Water Bottle
- Fill a casserole dish with ice.
- Carefully add about half a cup of hot water to the bottle. This should be about enough water to cover the bottom inch of the bottle.
- Put the cap on the bottle and gently shake it up to get the hot water moving around in the bottle.
- Lay the bottle on it’s side on top of the ice-filled casserole dish.
- Gently pour some ice water on top of the bottle to help it cool down quickly.
- Go ahead and pick your bottle up and examine it. Why do you think it got crushed?
Step 1: Pour Ice Into a Casserole Dish
This first step is pretty easy, but it is important to use a casserole dish or a large bowl that is big enough to fit a 2-liter bottle laying on its side.
Then fill your dish with a generous amount of ice cubes. If you have an ice maker in your freezer, you will want to make sure you save enough ice for this (don’t make the same mistake I did and use all your ice the night before).
Step 2: Add Some Hot Water to The Bottle
If your kids are doing this experiment, make sure they have some adult supervision for this part to prevent any burns. You want to pour some very hot, but not quite boiling water into the 2-liter bottle.
You don’t need a whole lot of water. About 1/2 cup should be plenty and should be about an inch deep in the bottle.
It’s also a good idea to use a funnel when pouring the steamy water in. This will again help prevent anyone from getting burnt and from making a mess.
Step 3: Tighten Up the Cap and Shake The Bottle
Now that you have some hot water inside the bottle, it’s important to quickly screw the cap back on. You want to trap the heat inside the bottle and you even want to shake the bottle up a little bit too.
Shaking up the bottle for about 10 seconds or so will help splash the hot water around inside the bottle. This will warm up the plastic of the bottle and even heat up the air inside the bottle too!
Step 4: Put the Bottle on Ice
Leave the cap screwed on your bottle tightly and then quickly lay your warm bottle on its side on top of the ice-filled casserole dish.
The idea of this is to make the air inside the bottle go from hot to cold as quickly as possible. The faster the temperature drops from hot to cold inside the bottle, the more dramatic the crushing of the bottle will be!
Step 5: Pour Ice Water on Top of The Bottle
To help your bottle cool down more quickly and speed up the crushing process, gently pour some cold and icy water over the bottle.
Now we have ice underneath the bottle and ice water pouring over the top of the bottle to really cool it down.
This will continue to drop the temperature of our once very warm bottle, while also decreasing the air pressure inside the bottle at the same time.
You should also see and hear your bottle starting to crush a little bit too!
Step 6: Pick Up Your Bottle and See if it Looks or Feels Any Different
As long as you followed the steps above, your plastic bottle will look a little different than when we started this experiment.
It should show some signs of denting and crushing in from the sides of the bottle. But don’t worry, if you unscrew the cap some air will rush into the bottle and should pop the bottle back into shape!
What Causes The Plastic Bottle to Collapse?
The science behind how this collapsing plastic bottle experiment works is all thanks to the difference in air pressure that is created from heating up and cooling down the bottle quickly.
When hot water is added to the bottle and the cap is screwed on, the hot water heats up the air inside the bottle. The hot air inside the bottle expands and tries to escape but has nowhere to go.
As a result of the air temperature inside the bottle increasing, the air pressure also increases inside the bottle. The pressure on the inside of the bottle becomes higher than the air pressure on the outside of the bottle.
Now that the warm bottle has high-pressure air inside, we cool it down quickly by putting it on the ice cubes and pouring ice water on it.
As the air inside the bottle cools quickly, the air pressure drops quickly inside the bottle.
Once the air pressure is lower inside the bottle and higher on the outside of the bottle the outside force of the air pressure pushes down on the bottle and collapses it.
The amazing thing about air pressure is that you can do anything from collapsing a plastic bottle with it to this Rising Water Experiment Step by Step.
How Air Pressure Relates to The Weather:
The high pressure that caused the plastic bottle to crush is the same way that high pressure can cause a basketball or football to go flat after going on a trip to the mountains!
Let me explain: Have you ever taken a trip to the mountains and brought a football along to play some catch!?
If you have done this, you may have noticed that your football felt much more inflated in the mountains (at a higher elevation) than it was when you left your house (at a lower elevation).
Once you get home from the mountains you then notice your football is even flatter than before and has lost a lot of air! Did your football get a hole in it!? Most likely not.
What actually happened is that the lower pressure in the mountains (there is less air on top of you because the atmosphere is thinner in the mountains) allowed the football to expand and some of the air escaped the football.
When you came back home to a lower elevation the air pressure increased again and there is higher pressure pushing down on the football.
This leads to higher pressure outside the football pushing down on the air inside the football and makes your football feel like it needs some more air!