To enable you to read the level the fluid has reached
A glass stem thermometer measures temperature by using the principle of thermal expansion. The liquid inside the glass stem expands or contracts with temperature changes, causing the level of the liquid to move up or down the scale. This movement indicates the temperature.
In this answer I m referring to the normal thermometers. Not the electronic thermometers. There is a very very thin capillary tube incide the thermometer which is filled with mercury and it has a bulb aT one end. When it touches a surface, the mercury expands, rises in the capillary and the temperature is shown.
A so-called "glass" thermometer has a small bore-hole in the center of the glass that has some liquid in it. It's the activity of the liquid in the narrow hole that makes the thermometer a thermometer.
As the temperature rises or falls the liquid in the reservoir (bulb) of the thermometer rises or falls ) the liquid expands (heats up) or contacts (cools off). The volume change is made visible in the capillary (tube) in the part of the thermometer with the scale. This is the only part of the thermometer into which the extra volume and expand.Increasing the volume of fluid or decreasing the diameter of the capillary makes the changes more apparent/
use a thermometer.We can feel how hot or cold something is. However, sometimes things are just too hot or cold for us to feel safely. At other times we need to know exactly how hot or cold something is. When we need to measure temperature correctly we need to use an instrument called a thermometer. This measures temperature in degrees Celsius [sometimes called centigrade] or degrees Fahrenheit. There are different types of thermometers for different situations. A medical thermometer, for example, needs to be very accurate. It measures in fractions of degrees. When we are ill, even tiny changes in temperature are important. Some thermometers use a liquid that moves up a very fine glass tube. Most room thermometers, and outdoor thermometers are like this. The liquid is either mercury [ which is poisonous] or coloured alcohol. As liquids get warmer they expand [get bigger], and move up the tube. Water expands too, but not as much as alcohol and mercury. Thermometers that might be used by small children are not made of glass. They use a digital display which lights up the temperature. Inside the displays are chemicals that change colour according to the temperature.
A glass stem thermometer measures temperature by using the principle of thermal expansion. The liquid inside the glass stem expands or contracts with temperature changes, causing the level of the liquid to move up or down the scale. This movement indicates the temperature.
because it is cheap and it does not expand on heating therfore it doesnt break
The substance in the thermometer stem rises up because it expands when heated. This expansion is due to the particles within the substance moving more rapidly and spreading further apart, causing the substance to take up more volume and rise up the stem of the thermometer.
Because Mercury expands in heat, it is more accurate than other elements used in thermometers.
An ordinary glass fever thermometer is typically made of a sealed glass tube filled with mercury or dyed alcohol. It has a calibrated scale along the length of the tube to measure temperature. When the thermometer is placed in contact with a warm object, the temperature causes the liquid inside to expand and rise up the scale, indicating the temperature value.
shove it up ur ASSS
In this answer I m referring to the normal thermometers. Not the electronic thermometers. There is a very very thin capillary tube incide the thermometer which is filled with mercury and it has a bulb aT one end. When it touches a surface, the mercury expands, rises in the capillary and the temperature is shown.
A so-called "glass" thermometer has a small bore-hole in the center of the glass that has some liquid in it. It's the activity of the liquid in the narrow hole that makes the thermometer a thermometer.
Mercury in glass thermometers pose a greater health hazard if broken, as mercury is a toxic substance that can be harmful if inhaled or ingested. Alcohol in glass thermometers are considered less hazardous as alcohol is not as toxic as mercury. It is still important to clean up any broken thermometer carefully to avoid injury.
Charles WingerThe Thermometer was invented by Galileo Galilei in 1593. His thermometer consisted of water in a glass bulb; the water moved up and down the bulb as the temperature changed.
It's made of glass.
As the temperature rises or falls the liquid in the reservoir (bulb) of the thermometer rises or falls ) the liquid expands (heats up) or contacts (cools off). The volume change is made visible in the capillary (tube) in the part of the thermometer with the scale. This is the only part of the thermometer into which the extra volume and expand.Increasing the volume of fluid or decreasing the diameter of the capillary makes the changes more apparent/