Science

10th November 2006 at 00:00
Age 11-16

A favourite pupil misconception is that gas has no weight. This is because gas particles are widely spread out, unlike solids or liquids, which are condensed with particles touching.

To demonstrate that air has weight, take a two-litre plastic bottle and insert a rubber bung with a short glass tube and rubber tube with screw clip, which fits a cycle pump with a non-return valve. Place the bottle on a top-pan balance and set to zero.

Now pump air in - about 40 strokes. Tighten the clip and weigh the bottle again. It should now be about 1g. (Rehearse the number of pumps it takes to get 1g of air into the bottle).

Unscrew the clip a little to let the air out, quick enough to hear the hissing but slow enough to see the balance return gently to zero. Place 1g of modelling clay on to the bottle, which is still on the balance, to return it to its air-filled weight. This demonstrates there is the same amount of matter in that tiny ball of modelling clay as in 40 pump-fulls of air

Resources at Science Issues and the National Curriculum

Website www.glos.ac.ukscience-issues

Keith Ross teaches science education at Gloucestershire university

Subscribe to get access to the content on this page.

If you are already a Tes/ Tes Scotland subscriber please log in with your username or email address to get full access to our back issues, CPD library and membership plus page.

Not a subscriber? Find out more about our subscription offers.
Subscribe now
Existing subscriber?
Enter subscription number

Comments

The guide by your side – ensuring you are always up to date with the latest in education.

Get Tes magazine online and delivered to your door. Stay up to date with the latest research, teacher innovation and insight, plus classroom tips and techniques with a Tes magazine subscription.
With a Tes magazine subscription you get exclusive access to our CPD library. Including our New Teachers’ special for NQTS, Ed Tech, How to Get a Job, Trip Planner, Ed Biz Special and all Tes back issues.

Subscribe now