It is widely known that physicists like thermal cameras. As more and more people have been asking whether I have become a mathematician, I knew it was now or never. I got myself a model that uses a phone app as a screen and user interface. It has its own battery and is connected over Bluetooth, this has the nice benefit that you can put it somewhere and use the phone as a trigger for selfies and group pictures, certainly one of the most prominent use cases of thermal cameras. The IR sensor resolution is 256 x 192 pixel, which sounds unimpressive compared to your 500 MP phone camera, but is actually at the upper end of the range of phone-attache IR cameras.
So first I took a selfie, which, luckily, doesn’t look scary as all. I assume that between 34 and 35 degrees is the recommended nose temperature.
Then I took a walk through the Maths institute. Look, the dishwasher is running in the kitchen and someone forgot to switch the coffee machine off.
My laptop has been doing calculations for tropical field theory for the last few weeks. It assumes an equilibrium temperature of 45 degrees at the keyboard, and 80 degrees at the air exhaust.
What is also interesting is that you can see for several minutes if a person has used a laptop on a desk. Here is an empty desk in our office a few minutes after my colleague left.
Then I learned that you can manually set the temperature range and prevent the picture from being entirely medium-orange. This is particularly useful for outdoor pictures when you are interested in the details of a building, but the picture also includes warm persons or cars, or the freezing blackness of the void (i.e. the sky). Here is Magdalen College:
Finally, I considered the towel dryer radiator in my bathroom. It has an electrical heating element, but only in one corner, and the heat is transported through a liquid that is contained in the entire radiator. After switching it on, one can watch a convective motion setting in: The liquid is heated at one point, then it moves upwards towards the top of the radiator, and the resulting pressure difference forces it sideways and finally down. The hottest point stays around 30 degrees during this time. Only after maybe 20 minutes, the circular motion has distributed the hot liquid everywhere, and the whole radiator starts getting hotter than that. If it is on for very long, it eventually reaches around 55 degrees.
