The wall of bulb is made thin in laboratory thermometer because if the wall of bulb is made thick , it cannot respond quickly to the change in temperature as glass is poor conductor of heat so that reading may not be exact.
Laboratory thermometers are devices used to measure temperature. ... While a lab thermometer can measure how hot or cold a sample or environment is, the range of measurement can vary widely between models.Laboratory thermometer consists of a bulb with a long capillary tube. The wall of the bulb is made thinner and the capillary tube is made narrower to make the thermometer more sensitive. Mercury thermometer expands and contracts according to the rise or fall in temperature.
Its made of glass with very thin walls to allow the heat from sample being measured to reach the liquid quickly for fast response and quick reading (improves the quickness of response by the thermometer). ... — has a vacuum above the liquid column so there is no resistance to the expanding liquid.Small expansion of the liquid in the liquid bulb will cause a big change in the length of the liquid thread in the capillary tube as it is made narrow. The narrower the bore, the higher the sensitivity.The bulb of the thermometer needs to be thin because the glass, while a good material for most of the thermometer design, is a poor conductor of heat. The mercury inside is metal and an excellent heat conductor, but the glass is an insulator.
The narrow bore of te capillary tube makes the thermometer more sensitive. This is because a small expansion of the mercury in the bulb will cause a big change in the length of the mercury thread. The bulb is made of thin glass so that heat can be conducted quickly to the liquid.Mercury is one of the most familiar materials used in liquid thermometers. Other liquids, such as kerosene or ethanol, may also be used in these types of thermometers. When heat rises, the liquid expands from a bowl or bulb into the empty area, climbing up the tube.