They used to sell a much larger piece of the sheet and I am sure it is in the online catalog.
One thing I have seen and not tried yet is the modeling of the Sun’s energy incident on the surface of the Earth and how this causes seasons. There are some great ideas in this SEP publication. SEP thermochromic booklet
Here is a site with a really good explanation of how it works.
I usually get it out when doing diffraction gratings and path length along with my fire opal and a quick mention of Bragg’s Law.
Great demos Dave, as usual! I love the slow motion video and the slices of thermochromic paper on the small football. It really shows nicely how the tilt of the earth axis is responsible for the seasons rather than the distance from the sun.