Signal

Have you ever played a game of Marco Polo in the pool? It's a game where one person is "it" and has to close their eyes and try to find the other players by listening for their voices. The other players have to shout out "Marco" and the person who is "it" has to say "Polo" in response.

A signal is like Marco Polo, but instead of using your voice to communicate, you use something else like a flashlight, a flag or even your phone. A signal is a way of sending a message or information from one place to another.

Just like how "Marco" tells the person who is "it" where the other players are hiding, a signal tells something or someone else what you want them to know. For example, when you press the button on the TV remote, that's a signal to the TV to change the channel.

Signals can travel through different things like wires or airwaves. Just like how sound travels through the air in Marco Polo, signals also travel through the air using something called radio waves.

So the next time you play Marco Polo in the pool, remember that you're actually using signals to talk to each other!