Answer:
What does radar what? What does it do? Weather radar scans layers of the atmosphere to find rain and storms. Rain or clouds will reflect the radar signal back to the transmitter, indicating a cloud heavy with rain or a lighter, non rain cloud.
Radar may also be used at an airport to tell the controllers where planes are both in the air and on the ground.
Radar may also be used in a plane to tell the pilots if their are other planed in the sky near them that they should know about.
Radar may be used on a car, (usually the nicer more expensive cars), to tell the driver if there is something behind them that they are about to back over or if they are going too fast and getting too close to the car in front of them. Some cars will automatically slow down if they are too close to the back bumper of the car in front of them.
When radar is used underwater, it is called sonar.