A filter is like a magic tool that helps you pick out only the things you want. Imagine you have a big box of toys, but you only want to play with the red ones. A filter would be like a special pair of glasses that lets you see only the red toys, leaving all the others behind. This way, you can have fun with just the toys you like the most.
Another way to think about a filter is like a sieve you use when playing in the sand. When you scoop up sand and shells, the sieve lets the tiny grains of sand fall through, but it holds onto the bigger shells. The filter helps you find the treasures hidden in the sand by keeping the things you don’t want out of the way.
You can also think of a filter as a strainer when making pasta. When you pour the pot of water and pasta into the strainer, the water goes away, and the yummy pasta stays. The filter is like the strainer, letting go of what you don’t need and keeping what you want.