Detecting thermal energy

The point was made early in this set of pages that thermal energy is hard to notice. It takes 50,000 Joules to get a cup of coffee hot, which seems like a much less exciting event than shooting the coffee 50 Km into the air (This also requires 50,000 Joules)! However, with the aid of the thermal sensing sheet we have been able to detect thermal energy:

The idea that energy is conserved is relatively new to science. Optics, the laws of motion, electricity, and magnetism were all well on their way to being understood before this idea was discovered, even though it is now regarded as fundamental. Part of the reason must have been that thermal energy was so hard to detect, that when other kinds of energy turned into thermal energy it just seemed to disappear. We hope that the thermal sensing strip and the activities of this section have made thermal energy seem more real, and made it easier to believe in the conservation of energy.

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Discussion of energy transformations