We posted a YouTube video of us using a thermal camera in the kitchen sink and running a number of experiments to see if thermal cameras can see underwater at different temperatures.
The video can be broken down into 2 sections. The first section we fill the sink with hot water and then do experiments with our hands, cold water and ice. In the second section we fill the sink with cold water and put in our hands and hot water.
Spoiler alert. Based on our observations it appears that thermal cameras cannot see underwater and it does not matter the temperature of the water.
Here is the video. Enjoy.