No worries! Heat transfer is actually a pretty complicated topic. There are entire college-level engineering courses on it
. For even more background info, there are three types of heat transfer:
- when heat passes between two solid objects that are touching each other. You can feel this when you press your hand up against something warm or cold.
- when heat is transferred by moving air or water - you feel this in a cool breeze on a hot summer day.
- this is heat transferred by light (or other types of electromagnetic radiation that we can't see, like infrared). You feel this when you lay outside on a sunny day, or hold your hands in the air near a red-hot electric stove.
The challenge is that at first glance, this project just appears to be about radiant heat transfer (light heating up a t-shirt). But, you have that t-shirt wrapped around a jar with a thermometer inside, so as we discussed in the earlier posts, there are other factors at play:
- How much light gets through to the inside of the jar, heating up the air inside and the thermometer directly.
- How much light gets absorbed by the shirt, heating it up - that heat will then conduct
to the surface of the jar, and then heat the air inside.
Taking all that into account, here's a new thought - what if you take tiny pieces of fabric (of the same size and weight, but different colors) and JUST wrap them tightly around the thermometer? Eliminate the jar entirely. That might give you a better idea of how much the fabric itself is heating up, and eliminate the extra problems because there are fewer "layers" between the fabric and the thermometer.