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
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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{ 11 comments… read them below or add one }
i think that air doesnt have mas cause you cant actually prove it
On what do you base that comment, abigail, or are you just trying to be provocative?
I still cannot get it!
Did air has mass?
why?
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.
But what are other ways in proving it? other than the balloon hitting someone.
A full balloon weighs more than an empty ballon, showing that air has not only matter, but mass as well.
air has mass
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?
Another very nice little experiment, thanks Cristina!
cool im doing air in science and im in grade 6. i need help….. i dont get how air has mass
and im a girl and that pic is not me