Using Liquid Nitrogen to Demonstrate Charles' Law


                                                                                                Pics from LHA's open house. October 2004

1    Liquid nitrogen was poured into a large mortar. (not the container of choice! We could not find anything else, but a thick styrofoam container would have served as a much better insulator).

2.    Liquid nitrogen is at -196 C or only 77 K. Compared to a room temperature of 20. oC = 293 K this represents only 77/293 of the absolute temperature so it should cause the volume of the balloon to be reduced to 77/293 or about 26% of its original volume.

3    The balloon is rotated to cool as much of its contents as possible.

4.    As predicted, the air within the balloon now occupies a much smaller volume. If taken out of the liquid nitrogen, the balloon regains its original shape as its contents regain their lost kinetic energy.