Recent Post

Importance of Physical Exercise according ot age and sex

Importance of Physical Exercise according ot age and sex According to Age: Physical education is applicable for people of all ages. But programmes of physical education differ likings and dislikings for different age-groups. Not only physical exercise but also food, likings and dislikings and physical abilities are different for different age-groups. For example, physical ability of children is not equal to that of adults.  So to develop the abilies exercise through games should be introduced accordingly. Frog jumps, touch and back, crow jump or recreational games are some physical activities that can improve physical ability of children. Selection of exercise and games for adolescent should be done systematically. Standing in a line, exercise of hands and legs, running with a ball, touch and play, etc. and games and physcial exercise can be used to develop physical abilities of children. Remember, children and adolescents should not participate in weight lifting exercise. It causes h

Liquid Thermometer

Liquid Thermometer


Liquid thermometers are based on the principle of change of volume of the liquid with change in temperature. These thermometers are suitable for a narrow range of measurements. The most commonly used liquids are (i) mercury and (ii) alcohol. The range of the mercury thermometer is - 39°C to 357°C. Alcohol thermometers are used only to measure temperature near ice points.

Mercury Thermometer

Mercury is usually selected for use in liquid in glass thermometers for the following reasons:

  • It has a low specific heat and hence it absorbs little heat from the body whose temperature is being measured.
  • It is a good conductor of heat and takes the temperature of the body quickly.
  • It can be easily seen in a fine capillary tube and the thermometer can be made sensitive.
  • It does not wet the wall of the glass tube. This is an important point for the construction of a thermometer.
  • It has a uniform coefficient of expansion over a wide range of temperatures.
  • It remains a liquid over a large range. Its freezing point is -39°C and its boiling point is 357°C. 

You may also like

Comments

People Are Reading...

Objectives of Physical Education

Efficiency

Laws of Reflection

Importance of physical education

The Importance of Information and Communication Technology

How to make a telephone call