Radar is a technology that finds distant objects by sending out radio waves and detecting the echoes that bounce back. The word itself is an acronym: RAdio Detection And Ranging.

Here's how it works: a radar system sends out invisible waves (similar to light waves, but much longer) that travel through air, fog, clouds, or darkness. When these waves hit something solid, like an airplane, ship, or storm cloud, they bounce back to the radar receiver. By measuring how long the echo takes to return, the system calculates how far away the object is and what direction it's in.

Radar helps air traffic controllers track every plane in the sky, allows meteorologists to see approaching storms, and helps ships navigate safely through fog. Police use radar to measure how fast cars are traveling. Some cars now have radar systems that warn drivers if they're getting too close to another vehicle.