Do you know what an atom is? It's like a tiny little ball that makes up everything around us.
Now, if we take a special gas called helium and shoot it at some atoms, the helium gas bounces off the atoms and comes back to us. This is called helium atom scattering.
Scientists use helium atom scattering to study what happens when atoms and molecules interact with different surfaces. They can learn about the properties of these surfaces, like how smooth or rough they are, and how the atoms and molecules move around on them.
It's like when you play with your toys. If you throw a ball at the wall, it will bounce back to you. But if you throw it at a stuffed animal, it might not bounce back in the same way. Scientists use helium atom scattering to study how different surfaces interact with atoms and molecules in the same way you play with your toys.