A wave is like when you throw a stone into a pond and see circles moving away from where the stone splashed. Those circles are waves, moving through the water. Waves can be in water, but they can also be in the air, like when you hear music. The sound travels in waves to your ears.
Another way to think about a wave is like when you shake a rope up and down. You can see the rope moving in a wave pattern, going up and down, up and down. The wave travels along the rope from one end to the other.
Waves can also be like when you see a flag flapping in the wind. The flag moves in a wave-like motion because the wind pushes it up and down.
Waves are everywhere! Even when you watch the ocean, the water moves in waves. They can be big or small, fast or slow, but they all move in a similar pattern, going up and down, and carrying energy from one place to another.
Think of a wave like a dance that never stops, always moving and changing, bringing sounds, light, and even warmth to us.