Liquid- in-glass Thermometer

Liquid-in-glass Thermometer

LIQUID used should

- be easily seen

- expand and contract rapidly over a

wide range of temperature

- not stick to the glass walls of the the

capillary tube

Mercury is commonly used because

- it is good conductor of heat

- it has a high boiling point

- it expands uniformly when heated

- it is opaque and it can be seen easily

TEMPERATURE SCALE

Two fixed temperature are identified,as a high

and low points of the scale.They

are called fixed temperature,because

it can be reproduced in a laboratory

anywhere in the world.

Ice point,the lower fixed temperature is the

melting pont of pure ice whici is 0 degree celcius.

Steam point,the higher fixed temperature

is the boiling point of pure water which is 100 degree celcius.

SENSITIVITY of a thermometer can be increased with;

- capillary tube with a finer bore

- a smaller tube

- a glass bulb with a thinner wall