Give Now

A Moment of Science

A Science Joke: Hydrogen

Why is it that you can't put down hydrogen gas? Find out on this Moment of Science.

1922 US Army airship

Photo: US Army

Older airships, like this US Army one from 1922, flew using hydrogen.

Why is it that you can’t put down hydrogen gas? If you had a big balloon full of hydrogen gas, like the first gondola balloons pioneered in 18th-century France, you’d find that it rises in the air quite dramatically.

You know that a piece of wood will float in water, right? That’s because the wood is less dense than the water. When you’re in a buoyant medium, having a lesser density than your surroundings means you’ll float. Something with greater density than water, like a stone, will sink.

Now, air also has the quality of buoyancy. Anything less dense than the air will rise, just like a piece of wood held underwater and then let go. Hydrogen gas is only about one fourteenth as dense as air. So up it goes! In fact, it rises with such force that it can even haul up a huge balloon, with a gondola and riders!

Stay Connected

What is RSS? RSS makes it possible to subscribe to a website's updates instead of visiting it by delivering new posts to your RSS reader automatically. Choose to receive some or all of the updates from A Moment of Science:

Support for Indiana Public Media Comes From

About A Moment of Science

Search A Moment of Science