Name: Kinds of Clothes We Wear in Summer and Winter
Uploaded: 2019-07-19
Duration: 4 min
Description: In this video, we'll learn the effects of dark and light coloured surfaces on our body temperature. And by doing so, know the appropriate choice of clothing...

Question

Draw a labelled diagram of a mercury thermometer. How does it function? What is its use?

Accepted Answer

The temperature range of a clinical thermometer is from $35 ° C$ to $43 ° C$ which is very close to the human body temperature range. There is a permanent mark on the stem of the thermometer at $37 ° C$ which is the normal human body temperature. One side of the stem is made convex so that the reading is magnified and can be seen easily. The bulb is filled with mercury and there is a capillary tube that extends from the bulb into the stem. There is a constriction in the capillary tube above the bulb.

It is used to measure body temperatures by placing the bulb under the tongue or in the armpit. With the body heat, the mercury expands into the capillary and the reading is noted on the stem. The constriction helps in preventing the expanded mercury from flowing back freely into the bulb after taking the reading. The thermometer has to be jerked to force the mercury back into the bulb before the next use.

Draw a labelled diagram of a mercury thermometer. How does it function? What is its use?

Important Questions on Heat

Learn and Prepare for any exam you want !