my best suggestions:
1.) build box. test. put in a bag full of air. test. Fill the bag with water. test.
2.) build a thermoacoustic heat pump -- this may be difficult to get working but the priciples are fairly easy.*
these really are physics project with only marginal relevence to chemistry.
sorry, but for chemistry i can't really think of much.
2* acoustic heat pumps use pv=nrt. v, n, and r are all constants in the system build (a closed system with a fluid, not air), so changing p will change t. waves propogate down a tube and reflect back making standing waves maybe every inch or so (depends on frequency). you'll need to use a high enough frequcny that these standing waves are not too long. metal contacts are placed at what will be the peaks and the nulls of the standing wave (equally spaced). the contacts at the nulls will get cold while the contacts at the peaks will get hot. this makes the device into a heat pump.
1.) build box. test. put in a bag full of air. test. Fill the bag with water. test.
2.) build a thermoacoustic heat pump -- this may be difficult to get working but the priciples are fairly easy.*
these really are physics project with only marginal relevence to chemistry.
sorry, but for chemistry i can't really think of much.
2* acoustic heat pumps use pv=nrt. v, n, and r are all constants in the system build (a closed system with a fluid, not air), so changing p will change t. waves propogate down a tube and reflect back making standing waves maybe every inch or so (depends on frequency). you'll need to use a high enough frequcny that these standing waves are not too long. metal contacts are placed at what will be the peaks and the nulls of the standing wave (equally spaced). the contacts at the nulls will get cold while the contacts at the peaks will get hot. this makes the device into a heat pump.