1 . Themometer
A thermometer is used to measure the temperature of an object. Galileo invented a rudimentary water thermometer in 1593. He called this device a thermoscope. However, this form was ineffective as water freezes at low temperatures. In 1714, Gabriel Fahrenheit invented the mercury thermometer, the modern thermometer. The long narrow uniform glass tube is called the stem of a thermometer. The scales in which the temperature is measured is marked on the scale. At the end of the stem there is a small bulb which contains mercury in it. A capillary tube is inside the glass stem in which mercury expands when the bulb is kept in contact with a hot body. Mercury is toxic, and it is very difficult to dispose it when the thermometer breaks. So, nowadays digital thermometers are used to measure the temperature, as they do not contain mercury.
2 . Laboratory Thermometers
Laboratory thermometers are devices used to measure temperature. There are many types of lab thermometers such as differential, mechanical, logging, etc. Laboratory thermometers are progressively providing digital reading displays and are inputcapable to computer and software programs for logging purposes.
3 . Types of Thermometers
There are different types of thermometers that measure the temperatures of different things like air, our bodies, food and many other things. There are clinical thermometers, laboratory thermometers, Galileo thermometers and digital remote thermometers. Among these, the commonly used thermometers are clinical thermometers and laboratory thermometers.
4 . Clinical Thermometer
These thermometers are used to measure the temperature of the human body, at home, clinics and hospitals. All clinical thermometers have a kink that prevents the mercury from falling down rapidly so that the temperature can be noted conveniently. There are temperature scales on either side of the mercury thread, one in Celsius scale and the other in Fahrenheit scale.Since the Fahrenheit scale is more sensitive than the Celsius scale, body temperature is measured in
5 . Mercury laboratory thermometers
Mercury laboratory thermometers, used in some science laboratory, requirer special safety precautions. Alcohol laboratory thermometers, despite of its less dangerous nature, should still be handled carefully to any damage. There are several principles on which empirical thermometers are built, as listed in the section of this article entitled Primary and secondary thermometers. Several such principles are essentially based on the constitutive relation between the state of a suitably selected particular material and its temperature. Only some materials are suitable for this purpose, and they may be considered as thermometric materials.
6 . Thermometer Safety
You have to twist gently the laboratory thermometer and press it firmly, but dont use brute force when inserting a laboratory thermometer to a rubber stopper. If you could, put a drop of glycerin or other lubricant to make the laboratory thermometer slide more easily.
7 . Considerations
You have to hold your hand with distance of less than 1 inch from the stopper to avoid exerting torque on the thermometer. Thermometers can be divided into two separate groups according to the level of knowledge about the physical basis of the underlying thermodynamic laws and quantities. For primary thermometers the measured property of matter is known so well that temperature can be calculated without any unknown quantities. Examples of these are thermometers based on the equation of state of a gas, on the velocity of sound in a gas, on the thermal noise (see Johnson
8 . Types
Laboratory thermometer safety depends on the type of laboratory thermometer: broken alcohol thermometers and other nonmercurylaboratory thermometers only needs the same cleanup as any other broken glass. A broken mercury thermometer requires special cleaning procedures.
9 . Warning
High school and college students should never try to clean up a mercury spill from a broken mercury laboratory thermometer; instead, tell your laboratory instructor, turn off any heat sources. Trained department staff will come to clean up the spill.
10 . Temperature
Temperature is a measure of the degree of hotness or coldness of a body. The SI unit of temperature is kelvin (K). But temperature is usually measured in celcius (