simple questions on heat absorption project

[Guest]

The project is on what colors will absorb the most heat. We are going to paint glass jars, sit them in the sun, and record the water temp.
Can anyone answer these questions?

What is the cheapest and most efficient (and easy to find!) thermometer to measure the water temp? Is it possible to use the digital ones that measure body temp?

I was thinking of using acrylic paint b/c it is thicker than glass paint. Does anyone disagree or have another suggestion?

Thanks!

[Rvu]

Any thermometer will do, so long as it is within the heat range that you're expecting. For instance, on a very cold day, you would not expect the temperature to get very high... with a thermometer only measuring 40 - 50 degrees C, that wouldn't work very well... It all depends on what temperature you're expecting & what your thermometer's capacity is. Hope this helps.