Continuous-wave radar

Imagine you are playing hide-and-seek with your friends in a big forest. You need to find them, but you can't see them because they are hiding behind trees and bushes. You ask your parents for help, and they give you a special device called a radar.

The radar sends out a signal, just like your voice when you shout "Marco" during the game. The signal is a kind of invisible wave that travels through the air and bounces off of objects like trees and bushes. When the signal comes back, the radar listens for it, just like you do when you listen for your friends to reply "Polo."

Continuous-wave radar is a special kind of radar that sends out a continuous signal, without stopping or changing. It's like when you keep saying "Marco" over and over again instead of waiting for your friends to respond. The radar listens for tiny changes in the signal that happen when it bounces off of objects. These changes tell the radar how far away the object is and what it might be.

Continuous-wave radar is used a lot in airplanes to help pilots "see" even when it's cloudy or dark. It can also be used to tell how fast a car is going or to track a boat on the water. Pretty cool, right?