MERCURY THEROMETER
thermometer consisting of mercury contained in a bulb at the bottom of a graduated sealed glass capillary tube marked in degrees Celsius or Fahrenheit; mercury expands with a rise in temperature causing a thin thread of mercury to rise in the tube.


ALCOHOL THERMOMETER
An alcohol thermometer is a temperature measuring equipment that is made up of a glass capillary tube that is marked with Celsius or Fahrenheit degrees symbols and contains alcohol that rises when it expands or falls when it contracts due to the change in temperature. Alcohol thermometers are also known as spirit thermometers.

Alcohol thermometer is mainly used as a substitute for the mercury-in-glass thermometer since these two types of thermometers works in a same way. A mercury-in-glass thermometer is a thermometer that has mercury in its glass tube. What you can see in an alcohol thermometer is an organic liquid which is seen in a glass bulb that is connected to a capillary of the same glass whereby the end is closed with an expansion bulb. The organic liquid in the alcohol thermometer can be pure ethanol, toluene, kerosene or Isoamyl acetate. The types of organic liquid used in an alcohol thermometer will depend on the manufacturer and the working temperature range.


BIMETALLIC THEROMETER
The bimetallic thermometer consists of a bimetallic strip. A bimetallic strip is made of two thin strips of metals which have different coeffcients of expansion. The two metal strips are joined together by brazing, welding or reveting so that the relative motion between them is arrested.

The bimetallic strip is in the form of a cantilever beam. An increase in temperature will result in the deflection of the free end of the strip as shown i diagram. This deflection is linear and can be related to temperature changes.

__________________
It's Not Over 'til I Win