Weather Experiments Part 2

The next experiment requires a wine bottle, wine saver pump and miniature marshmallows. To start, place miniature marshmallows into the bottle to about a third or a quarter full. Place wine saver valve over the bottle opening then start pumping. Check out the video below keeping a close eye or the marshmallows. As I pump, think to yourself am I pumping air into the bottle or pumping air out of the bottle.

If you guessed I was pumping air out, you would be correct. As I pump air out of the bottle the air pressure in the bottle is lowered. Inside of the miniature marshmallows are pockets of air which expand in response to the lowering of air pressure inside of the bottle. This causes the marshmallows to expand or grow. As the valve is pushed to allow outside air back into the bottle, the air pressure equalizes inside and outside of the bottom so the marshmallows shrink back to normal size.

Check out the third entry which has to do with compressional warming. Most kids love this one when I demonstrate at schools.