Uses of radar

The uses of radar give great reliability to sea and air tra­vel. A radar set on a ship can provide the captain and the pilot with complete information about the objects around the ship. Radars will prevent collisions in fog and aid a ship to sail safely regardless of night or weather. Similarly airplanes will be able to fly over mountain ranges in storms and affect blind landing during 'poor visibility. The wide use of radar sets in our everyday life will make air and sea entirely safe.

Radar is useful in the investigation of the ionosphere. Re­flections from the various regions of ionization in the upper atmosphere are easily obtained and it provides very useful results. Meteorology is making increasing use of radar for cloud and thunderstorm detection. Radar is successfully used in launching rockets into space and in radar navigation of space ships.

WIRELESS WAVES

What is wireless wave? The well-known analogy of a stone dropped into a pool of water and producing ripples on the sur­face of the water gives a useful idea of what a wave might look like if only it were visible to the human eye. The waves are actually set up by the very rapid to-and-fro motions of the electrons which constitute the current in the aerial. They move backwards and forwards at the frequency of the current and the waves are sent out, or radiated, in all directions.

The waves travel outwards at a very high speed; in fact they travel at the speed of light.

The waves travel on medium. This medium is called the ether. We cannot see or feel this ether; in fact we are only aware of it by means of such indirect effects as listening to a wireless programme. The medium enables, wireless waves to travel from one place to another at the enormous velocity.