An excavator is a big machine that looks like a robot with a long arm and a bucket. It helps people move dirt and rocks when they are building things.
Imagine you have a really big toy that helps you dig in the sand. The excavator digs in the ground and scoops up dirt, just like you scoop sand with your shovel. The big arm can reach far and lift heavy things too!
Excavators can also help make holes in the ground for things like houses and roads. They are very strong and helps builders do their work quickly.
So, when you see a big excavator, think of it like a special helper that digs and moves dirt to build new things!