Science Buddies: "Ask an Expert"

I'm a bit confused on how to build a psychrometer. Like, I have the two thermometers and piece of Styrofoam, so do I just stick the two ends of the thermometer in the Styrofoam? Or do I attach them laying down?

Also, the dry thermometer temperature is supposed to be greater than the wet thermometer temperature, but mine keep coming out reversed. Is it because it is very cold out when I'm doing this? Should this experiment be conducted in warmer weather?

Hi,

The styrofoam is just to hold the thermometers in place. The bulbs have to stick out beyond the foam and have free access to moving air.

Are you trying to measure relative humidity outside? How cold is it? If you are, try measuring the relative humidity inside the house. Both thermometers have to be at the same temperature before you wet the gauze and start the fan.

Hope this helps. Let us know if you have any trouble calculating the RH.

Sybee