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Why do some balloons float and others don't? |
by Mya Kagan (whyzz writer) >> more about the author
Float on up
You may have noticed that the balloons you blow up with your mouth never float up in the air like ones you might get at the store or see at a party!
The reason this happens is that balloons you blow up yourself are filled with the air from your lungs, while balloons that float are filled up using something else: a special gas called helium that usually comes from a special helium tank.
Believe it or not, helium weighs even less than air! Because helium is so light, it basically “floats on top” of any of the heavier air around it! Even when helium escapes from a balloon (like if the balloon pops) it floats up above the air around it. (We just can’t see it doing so because it looks the same as air!) – This is what makes certain kinds of balloons float up, up, and away!
Float on up
Find out if you can get a helium balloon with a long string at the store, and then try out this experiment!
Collect a few different things to tie to the end of the string on your floating helium balloon. Think about stuff like a bag of coins, small toys, empty cans and bottles, or maybe a sock or a t-shirt.
Tie different items around the end of your balloon, and then study which of them the balloon is able to lift up! Make sure you try this experiment indoors, so that you can have a grown-up on a step-ladder help you retrieve the balloon after each try. (If you did it outside, your balloon would float away!)
What do you notice about the things that the balloon can “carry” and the things that it cannot? Does it seem to be related to shape? Texture? Color? Weight??
