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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

Types of thermometer

Types of thermometer

There are different kinds of thermometers.

1. Liquid Thermometers

These thermometers are based on the principle of change in volume of a liquid with change in temperature. Mercury and alcohol thermometers are based on this principle.

2. Gas Thermometer

These are based on the principle of change in pressure or volume with change in temperature, e.g., Callendar's constant pressure thermometer, constant volume hydrogen thermometer, etc.

3. Resistance Thermometers

These are based on the principle of change in resistance with a change in temperature, e.g., platinum resistance thermometer.

4. Thermoelectric Thermometers

These are based on the principle of thermoelectricity, i.e., the production of thermo-E.M.F. in a thermo-couple when the two junctions are at different temperatures.

The various thermometers commonly used are:

  • Copper and constantan

  • Iror and constantan

  • Chromel and constantan

  • Chromel and alumel

  • Platinum and Rhodium

5. Radiation Thermometers

These are based on the number of heat radiations emitted by a body e.g., furnaces. These instruments are known as pyrometers.

6. Vapour Pressure Thermometers

These are based on the principle of change of vapor pressure with change in temperature. These are used to measure low temperatures. e.g., helium vapor pressure thermometer, etc.

7. Bimetallic Thermometers

These thermometers are based on the principle of expansion of solids. A bimetallic strip is taken in the form of a spiral. Its one end is fixed and the other end is attached to a long pointer. The pointer moves on a scale, calibrated in degrees. These thermometers are used in meteorology for recording the changes in temperature during the day. They are also used to measure temperatures at high altitudes.

8. Magnetic Thermometers

These thermometers are based on the principle of change in the susceptibility of a substance with temperature. These thermometers are useful for measuring low temperatures near the absolute zero temperature.

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