This super easy and fun activity uses the physics of air pressure to create an air gun out of a balloon and a plastic bottle. It’s time to have some fun and learn How to Make a Bottle Gun.
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If you are looking for something to entertain your kids with, look no further! This bottle gun activity will have the kids blasting air bullets around the house in no time!
How to Make a Bottle Gun
- Empty Plastic Bottle (16-20oz size works best)
- Electrical Tape
- Scissors or Utility Knife
- Small Foam Ball
- Empty Paper Towel Roll
How to Make an Air Gun With a Bottle
- Use scissors to cut the bottom inch or two off the plastic bottle.
- Cut off the neck of the balloon.
- Slide the remaining part of the balloon over the cut end of the bottle.
- Use electrical tape to secure the balloon to the bottle.
- Hold the bottle with one hand while pulling the balloon back with the other. Then release the balloon to shoot a “bullet of air.”
- Add an extra twist by shooting a foam ball out of the bottle gun.
Step 1: Cut the Bottom Off a Clean Bottle
Instead of throwing your next empty soda bottle into the recycle can, keep a few of them aside for this fun activity. The 16-20oz bottles are just about the right size for this bottle gun experiment.
Make sure to clean your bottle out and then use a pair of scissors or a utility knife to cut the bottom of the bottle off.
Side Note: Make sure to do this part involving scissors for your kids, or with them under close adult supervision. We don’t want anyone getting hurt!
I like to cut all the way around the bottle about an inch from the bottom of the bottle. The idea here is to create a round, smooth surface to connect and tape a balloon to the bottom of the bottle.
Make sure to trim off any rough plastic shards from where you cut. This will reduce the chance of the balloon getting punctured.
Step 2: Cut the Balloon
Using your pair of scissors, cut the narrow part (the neck) of a deflated balloon.
Depending on the size of the balloon you are using, a good rule of thumb is to make a cut about 1/3 of the way up the balloon from where the neck starts.
This should leave you with the 2/3 of the balloon left that is the bigger, wider part of the balloon. That way the balloon material can stretch over the bottle better.
Step 3: Slide The Balloon Over The Bottle
Use the larger part of the balloon that you cut to slide it over the bottom of the bottle that you cut. You may need to stretch the rubber latex of the balloon a little bit for it to fit over the bottle.
Make sure the balloon material is securely in place and overlapping the bottle by about an inch all the way around the diameter of the bottle.
Step 4: Tape The Balloon to The Bottle
Once the balloon is snug around the bottle, grab some tape and wrap it around the bottle and balloon.
I used electrical tape and it worked great, but you could also use plastic tape, or even duct tape if you wanted.
The idea is to secure the rubber of the balloon to the bottle so that it is airtight and can withstand the pressure that the air gun will create. So go ahead and layer up that tape!
Step 5: Get Ready to Fire Your New Bottle Gun
Now all that is left to do is point your gun towards a target and fire away! I like to stand up some empty toilet paper or paper towel rolls on a table and then see if I can shoot them down with my new air bottle gun!
To do this you will want to point the opening of the bottle (the end you would drink out of) towards your target. Then pull back on the rubber balloon on the bottom of the bottle.
Pull the rubber back until you can feel some resistance. Then release the rubber balloon and watch as your “magic air bullet” is forced out of the bottle opening and knocks over your paper towel roll target!
Step 6: Shoot Foam Balls Out of Your Bottle Gun
After you have enjoyed some time shooting air out of your bottle gun, why not try a little twist!?
I found some styrofoam balls that were about 3/4 of an inch in diameter to shoot out of the bottle gun. These work perfectly because they are about the same size as the opening in the bottle.
Load your bottle gun with these foam balls by fitting them snugly into the opening of the bottle. As you pull back the rubber and release it to shoot, the air pressure inside the bottle will force the ball out of the “chamber”!
The kids can have a blast target shooting with these! They may even want to have a bottle gun “nerf war” too! My only advice would be to put on safety goggles before any type of bottle gun war as they can shoot pretty hard!
How Does a Bottle Gun Work?
A bottle gun works by decreasing the air pressure inside the bottle (or chamber) and then rapidly increasing the air pressure inside the bottle.
When the rubber of the balloon is pulled back on the bottom of the bottle, it creates more room for air inside the bottle and the balloon. As a result, air from outside the bottle rushes in and tries to fill the extra space.
When the rubber of the balloon is released, the available area for the air decreases, which means there is now more air crammed into a smaller area.
All of this air being pushed by the balloon back into the bottle creates increasing pressure in the bottle.
As the pressure increases inside the bottle, it looks for a way to escape and does so with a spurt of wind, otherwise known as an “air bullet” rushing out of the opening of the bottle!
That “air bullet” is strong enough to knock over light objects like empty paper towel rolls from several feet away…if your aim is good enough!