Seriously I work outside and why is the feels like a real temp and the temp on record is taken in the shade?
In: 75
Sunlight heats up the thermometer (transfer of heat from the sun to the thermometer by light, by radiant energy). We want the temperature of the air, not the temperature of the air plus how much heating the sun is making on that object. Unless you actually do want the amount of heating caused by the sun, and then the cooling effects of interaction with the surrounding air is the problem.
The idea of a temperature measurement using a thermometer is that the mass of the thermometer gains, or loses, heat to the material it is immersed in. The thermometer is at thermal equilibrium (in balance with) the temperature of the surroundings. We want heat transfer by contact, not by radiant energy.
We do not actually want to know the temperature of the thermometer. We want to know the temperature of the air. That only works when the temperature of the thermometer is controlled only by the temperature of the air. Other heat (or cold) sources will give a false temperature reading, one where the thermometer says a temperature that is not the same as that of the air.
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