Physicopoeia

φυσικοποιΐα
THINGS I WISH I'D KNOWN WHEN I STARTED TEACHING PHYSICS

Domestic Thermal Imaging Pictures

These were taken using a FLIR E6 thermal imaging camera. The temperature given in the top left-hand corner of each image is the camera's assessment of the temperature of the object at the centre of that image (where the crosshairs are). The vertical scale on the right of each image shows the range of temperatures visible in that image, together with the colours the camera is using to represent them - this colour-coding changes from image to image, depending on what is being viewed.

 

However, the camera assumes that everything it's seeing has the same emissivity, so it will think objects of different colours will be different temperatures when actually they're in thermal equilibrium. Apart from that minor point, these are quite nice for teaching about infra-red emission in context.

 

The cupboard door on the left looks cooler because there's a freezer hiding behind it. You can see the hotter area just above the freezer, caused by the exhausted thermal energy from the freezer's cooling system.

A kettle coming to the boil with other items at room temperature.

Pouring hot water from the kettle into the cool mug.

About a minute later, the tea is brewing nicely next to a cold pint of milk. Notice how the IR from the hot mug is reflected by the glass milk bottle.

Lighting the gas, ready to cook pancakes. This allows you to see the fast turbulent convection caused by the burning gas.

Again, notice the IR from the burning gas being reflected by the shiny kettle on the right (which, itself, is still slightly warm from having boiled earlier).

A few seconds after the pan goes on to the gas hob, you can see the heat starting to conduct through the pan. The two little dark blobs in the pan are (cold) bits of butter, about to melt.

A few seconds later, the heat from the water is starting to conduct through the porcelain mug from the bottom up, just as the water was poured.

Eating a hot pancake with a cold drink on the table. Notice how you can tell the cup has been moved from an earlier position, leaving a cool patch on the table.

Walking across the cold kitchen floor barefoot, you leave behind warm footprints.

When you get up from your chair, you also leave behind a warm bum-print!

Mobile phones get warm when they're being charged, as do the charger units.

Hot water pipes under the floor leave behind a noticeable heat trace. Notice also the hot radiator at the top right of the image.

After clearing the table at lunchtime, you can see where the hot plates and cold glasses have been.

About to serve ice-cream. Notice how the camera has recalibrated its temperature scale to accommodate the ice-cream, so the table, which appeared purple in the previous image, now appears yellow.

Walking around the house barefoot tends to result in cold toes.

Ironing a shirt leaves a heat trace.