Radar is one of the most useful inventions, it uses radio waves to determine the range, angle and velocity of an object. Mostly it is used to detect aircraft, ships and guided missiles. Radar was made out of British-funded ‘death ray’ project during the run-up to WWII. The British government asked Scottish scientist Robert Watson-Watt to build a machine to destroy personal. Watson-Watt realized that death ray was impossible to build, but did suggest that radio waves could be used to monitor distant object.
