Did you know that you can squeeze an inflated water balloon into a glass jar with the help of some fire…without even popping the balloon!?
This super fun and easy experiment just requires a few basic materials along with some adult supervision! So let’s go ahead and learn about air pressure with this Balloon and Glass Experiment.
Get more cool Balloon Science Experiments here!
The best thing about this mind blowing science experiment is that both kids and curious adults will find it entertaining and educational!
Balloon and Glass Experiment
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- 1 large balloon (maybe a few extras just in case)
- Wide-mouth 1-quart mason jar
- Lighter or matches
- Piece of paper
- Safety Goggles
How to get a balloon in a jar experiment
- Inflate a balloon with a little bit of water and some air.
- Put a small piece of paper in a mason jar and light it on fire.
- Quickly place the balloon on top of the jar.
- Watch and enjoy as the flame goes out and the balloon is sucked into the jar!
Step 1: Fill up a balloon with some water and some air
The easiest way that I have found to get water into a balloon is to slide the mouth of the balloon over a faucet on a bathroom sink. Turn the water on low pressure while holding the balloon in place. Add enough water that the balloon is about the size of a baseball.
Carefully remove the balloon from the faucet while keeping the neck of the balloon pinched closed. This will prevent water from spraying all over in your face…trust me I learned this one firsthand!
Then go ahead and use your mouth to fill up the balloon with some air too. Once you have your balloon about halfway filled with air and the other half water, pinch the neck of the balloon and place it over the mouth of the jar.
Make sure the balloon is bigger than the jar mouth and will not fit in the jar and then tie it off. If the balloon is too small and fits right into the jar, then add a little more air before tying it off.
Step 2: Put some paper in the jar and light it on fire!
This is the part where adult supervision comes into play! It’s also a good idea to put on some safety goggles since we are dealing with fire and the possibility of a balloon bursting in your face too!
Now that we have taken the appropriate safety measures, let’s move on by tearing about 1/4 sheet of paper off of some scratch paper. Drop this paper into the bottom of your jar and light it on fire.
You may want to light the paper first and then drop it into the jar if you are using matches. If you have a long neck lighter, then it would be safer to drop the paper in the jar first and then use your lighter to ignite the flame in the jar.
Step 3: Set the balloon on top of the glass jar
It is important that you quickly, but carefully place the balloon on top of the jar. The reason you want to be speedy with this step is that you really need to get the balloon on the jar while the flame is burning nice and hot!
The heat of the flame plays a very critical part in the successful completion of this balloon and glass experiment, which we dive into the details of in a little bit.
Step 4: Watch as your balloon magically gets pulled into the jar!
Okay so the truth is that there is no “magic” to this experiment, but there is some pretty fascinating science behind it! You can watch the physics of air pressure unfold right before your eyes as the flame goes out and the balloon appears to be sucked into the jar!
Water balloon in a bottle experiment explanation:
Depending on how large your balloon was when you filled it up, it may not get sucked all the way into the jar but you will see at least half the balloon getting sucked into the jar. This happens due to a battle of high and low-pressure forces playing “tug of war” on the balloon.
Another example of this same air pressure principle demonstrated in a different way is my Rising Water Experiment Step by Step.
In both of these experiments, the air inside the jar is heated up very quickly by the flame inside. Hot air molecules move faster than cold air molecules and hot air also takes up more space in the jar.
The hot air increases the pressure in the jar and forces some air to escape between the balloon and the mouth of the jar. Immediately after the flame goes out, the air begins to cool, contract and the air pressure drops.
The drop in air pressure creates a low pressure inside the jar. Now the higher air pressure that is outside the balloon begins to try and fill the lower pressure jar and pushes the balloon into the jar in the process.
The amazing thing we learn from this experiment is that air pressure can control anything from a balloon in a jar, to the weather we experience every single day! Check out this article from the National Weather Service if you want to learn more about air pressure in the weather world!