Air has mass (and how to prove it!)

by Stephanie Chasteen on August 26, 2008

A teacher asked for a good experiment to show 8th graders that gas has mass.  “We have used balloons in the past,” she says, “but some of the kids still don’t make the connection.”

Paul Doherty replied:

I like to get a big weather balloon from a surplus store , inflate it until it is 1 meter in diameter or a little more and then a second balloon that is deflated.

Have a kid stand and throw the empty balloon at the back of their head…they feel almost no force.

Then throw the full one. It packs a noticeable punch due to the mass of moving air. the mass approaches a kilogram.

Of course you cannot weigh it using a scale due to buoyancy. You can only feel the mass by accelerating it or decelerating it.

And Eric Muller added:

Get some dry ice. It is solid Carbon Dioxide and it has noticeable mass. Lots of stores around the bay area sell dry ice. Many Safeways, Albertsons, bait shops, liquor stores, ice distributors and welding supply companies carry dry ice.

Weigh (or Mass) a chunk of dry ice. Put the chunk in a plastic bag and tie it off. It will sublimate and turn into a gas. The bag will expand noticeable. A solid, 44gram chunk of dry ice (that’s the size of a couple of fingers) will expand to around 22.4 liters of gas.

Gas has mass!

Pressure Pumper

Pressure Pumper

Here’s a cheap little toy from Arbor Scientific that also shows that air has mass — pump air into a small bottle using the pressure pumper. Why does it increase in mass?

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{ 18 comments… read them below or add one }

avatar abigail January 2, 2009 at 3:29 pm

i think that air doesnt have mas cause you cant actually prove it

avatar sciencegeekgirl January 2, 2009 at 3:37 pm

On what do you base that comment, abigail, or are you just trying to be provocative?

avatar amy April 12, 2009 at 11:44 am

I still cannot get it!
Did air has mass?
why?

avatar sciencegeekgirl April 14, 2009 at 4:38 am

Yes, air has mass. It’s made up of “stuff” — oxygen and nitrogen, for example, and those molecules do have mass.

If you hit someone with a balloon filled with air, they’ll feel it more than if you hit them with an empty balloon, for example.

avatar Tanner November 15, 2009 at 8:59 pm

But what are other ways in proving it? other than the balloon hitting someone.

avatar Misia September 13, 2010 at 9:08 pm

A full balloon weighs more than an empty ballon, showing that air has not only matter, but mass as well.

avatar Jordan March 11, 2011 at 2:50 am

air has mass

avatar Cristina January 16, 2012 at 2:04 pm

air has mass. you can prove it. buy two exactly the same balloons with the same weight in gram (make sure they have the same weigh in gram). fill the other balloon with air and weight it again. if you notice the weigh increases that means air has mass. now compare the balloon filled with air to the weight of an empty balloon. can you see the difference?

avatar Stephanie Chasteen January 17, 2012 at 6:35 pm

Another very nice little experiment, thanks Cristina!

avatar Shehzeen January 24, 2012 at 11:52 pm

cool im doing air in science and im in grade 6. i need help….. i dont get how air has mass

avatar Shehzeen January 24, 2012 at 11:54 pm

and im a girl and that pic is not me

avatar chloe reynolds October 1, 2012 at 10:44 pm

i am a 6th grader does air have mass?

avatar sean December 6, 2012 at 11:21 pm

Air has mass. Mass is not the same as weight. The gravitational pull on earth creates the earths atmosphere precisely because air has mass.

avatar Santana January 21, 2013 at 10:14 pm

We did that experiment with the two balloons where you weigh one and then fill it with air and then weigh it again but my question is WHY does air have mass?

avatar Stephanie Chasteen January 21, 2013 at 10:36 pm

Santana, nice question! My question back to you would be, well, what is air MADE of?

avatar Santana January 21, 2013 at 11:10 pm

Nitrogen, oxygen, argon and some other gases.

avatar Stephanie Chasteen January 21, 2013 at 11:12 pm

Great. And what can you tell me about those elements? (Hint, what does the periodic table tell us?)

avatar REGGIE February 12, 2013 at 9:28 pm

How do we know gas has mass?

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