20 Minute Labs: Balloon in a Bottle

A BALLOON BLOWING ITSELF UP?

Blowing up balloons is a fun way to celebrate a party or just add color to a room! But what if you could make a balloon blow itself up - inside a bottle?! 

In this week's 20 Minute Lab we'll do just that by using a few things from around the house.

First, try just blowing up a balloon in a bottle yourself. Place the larger, closed-end of the balloon into the bottle and attach the open-end of the balloon to the mouth of the bottle (like in the photo).

Now try blowing up the balloon by breathing into it. You can't! The bottle's already full of air and there's no room for any more!

But you can cheat using science. All you have to do is create a pressure change inside the bottle. Ready to try? Let's collect some everyday items and get started!

What You'll Need

• 1 clear glass bottle with a narrow neck
• 1 balloon (or more, as you may want to do this multiple times. New balloons work best!)
• water
• tablespoon
• hot pads

Let's Get Started!

1. Pour about a tablespoon of water into the bottle. 
2. Place the bottle in the microwave and heat for 1 minute until the water boils.
   NOTE: If your bottle is too tall for the microwave, you can set it tilted on its side in a microwave-safe bowl!
3. Ask an adult to carefully remove the hot bottle using hot pads and then hold it steady for you on a table or counter.
4. Quickly stretch the opening of the balloon over the mouth of the bottle. Keep the large end of the balloon pointing up and centered over the mouth.
5. Watch what happens! (Check out the video below to see how the experiment worked for us!)

Troubleshooting:

If your balloon doesn't get sucked into the bottle, you may not have heated it enough. Make sure the water is boiling. It can also take some time for the bottle to cool. We transferred ours outside so the winter air would cool the bottle faster!

If the balloon sticks to itself instead of getting pulled into the bottle, you may need to pull the larger end up to free it from itself.

WHAT'S GOING ON?

Here's what you likely saw:

At first, the balloon moved around a bit, then collapsed. Suddenly the balloon got sucked into the bottle and turned inside out! Then the balloon started to expand and inflate inside the bottle.

Wow! Why did that happen?

Heating the water in the microwave caused the water to boil. You probably remember that water changes form depending on temperature. When water freezes, it turns to ice; room temperature water is liquid; and when water boils it turn into a gas. This gas or steam is also called water vapor. 

As the water boiled and turned to vapor inside the bottle, its pressure increased. This increase in pressure pushed the air out of the bottle. At this point, you attached the balloon to the mouth of the bottle.

As the water in the bottle started to cool, the vapor turned back to a liquid. This lowered the pressure inside the bottle, making the air outside want to move into the bottle.

But the balloon was in the way! First, the air inside the balloon was sucked into the bottle. This created a vacuum and caused the balloon to collapse, get pulled into the bottle, and invert. Next, air from the room pushed into the inside-out balloon, stretching it out and inflating it! 

Check out more experiments with air pressure with our Egg in a Bottle experiment or our Self-Rising Water experiment!

SHARE WITH US!

Let us know what you did. Share your photos and results with us on Facebook, Twitter, Instagram, or send us an email to info@yellow-scope.com. We love getting your messages!

For more exciting experiments, check out our Yellow Scope Science Kits on the Shop tab of our website!