Quote:
Originally Posted by JSH
When you do your experiments just remember that infrared thermometers are not accurate on reflective surfaces. From Omega:
"In general, the higher the emissivity of an object, the easier it is to obtain an accurate temperature measurement using infrared. Objects with very low emissivities (below 0.2) can be difficult applications. Some polished, shiny metallic surfaces, such as aluminum, are so reflective in the infrared that accurate temperature measurements are not always possible."
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Remember, we are not launching space craft or building medical equipment.
A polished metal pot with boiling water in it shows 99.9*C. I call that close enough.
The only time it's a problem is if you aim at a mirror and there's a heat source in the reflection. IR from the heat source is reflected into your lens, so the temp reading will only be hotter.
Here's a photo of two mirrors, left inside at the same temperature:
One has a matte vinyl backing to the camera. Extreme opposites of the emissivity range. There's at most a 1*C variation between the two. Any heat source reflecting off the mirror would be immediately obvious.