Question

Why are thermometers that are used in weather stations shielded from the sunshine? What does a thermometer measure if it is shielded from the sunshine and also if it is not?

Short answer

Thermometers will show a higher reading than the original temperature of the environment in the presence of sunshine. So, it is shielded from sunshine at weather stations.

Step-by-step solution

Explain why the thermometers are shielded from sunshine in the weather stations.

Weather stations provide information about atmospheric conditions. In order to give this information, the exact temperature of the environment has to be measured. Sunshine makes its own contribution to increasing the prevailing heat energy surrounding the thermometer.

It will give a false measurement of the original temperature. So, for measuring the exact temperature of the atmosphere, it is shielded from the sunshine.

Compare the thermometer measurements when they are shielded from the sunshine and when are not shielded from the sunshine.

Sunshine will emit electromagnetic radiation. This radiation increases the heat energy, and the mercury in the thermometer will show a higher reading than the normal temperature of the environment. So, if you are shielding it from the sunshine, the thermometer will show the exact temperature that is required here.

Therefore, thermometers in weather stations are shielded away from sunshine in order to get the exact temperature of the environment.