ELI5: How do radar and surveillance systems work?

Radar and surveillance systems are like our eyes and ears, but they can "see" and "hear" much farther and sometimes even through things.

Imagine you are playing with a ball and you throw it against a wall. That's kind of how radar works!

• Radar sends out a radio wave "ball", which we can't see or hear.
• If the "ball" hits something, like an airplane, it bounces back.
• The radar system then "catches" the bouncing "ball" and figures out where the airplane is and how fast it's going.

• They watch what's happening and record it, just like your eyes.
• Some also have microphones to "hear" sounds, like your ears.
• This information is then sent to someone who can watch and listen to make sure everything is safe and okay.