I'm a physics major in Alaska, where it's not uncommon to have temperatures of -40. Are there any interesting experiments or designs that I can do in my freetime that are convenient because of the cold weather? I remember learning briefly about gradients being a source of power. If someone could give me a good keyword for that, I could better Google it (or look it up in my physics text books). Is the temp difference of -40 (outside) to 68 (inside my house) a large enough difference to even consider generating power (even if for fun).