MUTATING MARSHMALLOWS WITH MR. G

PROBLEM

What happens to marshmallows when you put them in a sealed jar and pump air on them?

PROCEDURE

Get a large threaded test tube.  Drop four mini-marshmallows inside.  Screw on a hand pump really tight.  Pump it 20 times while watching the marshmallows.  What happens to them?  Next try this same experiment using a vacuum pump.

MATERIALS

four mini marshmallows             test tube             hand pump

HYPOTHESIS

A. The marshmallows grow in size. (5)
B. The marshmallows get smaller. (4)
C. The marshmallows turn into one big blob. (4)
​D. The marshmallows turn into liquid. (3)

CONCLUSION

The marshmallows get smaller!  Air takes up space and the more air you squish into the test tube the less room the marshmallows have.  You've created a high air pressure environment.  The extra air is pushing really hard on the marshmallows.  Air is made up of 78% Nitrogen, 21% Oxygen, and 1% other gases?  All that air takes up a lot of space!

Check out the opposite situation.  With a vacuum pump the air is taken out and you create a low air pressure environment.  The marshmallow now has room to expand, but the container is really hard to open...until you let the air back in.