Have you ever played a game of tag or dodgeball? You want to make sure you don't bump into other players or objects so you try to keep an eye out for them and move out of the way.
Aircraft collision avoidance systems are like the eyes of an airplane. They help the pilots keep track of other airplanes that might be flying too close. These systems use fancy technology like radar and computers to figure out how far away other planes are and how fast they're going.
If the system thinks there's a risk of a collision, it will tell the pilots to fly higher or lower, or to turn to the left or right, to avoid hitting the other airplane. Just like when you're playing tag, the goal is to make sure the planes don't run into each other- because that would be very bad and dangerous!
Overall, these systems help keep everyone in the sky safe and avoid accidents.