What is Physical (physisorption)?

Physical adsorption, or physisorption, is when tiny particles stick to a surface without needing any special glue.

Imagine you're playing with your favorite toy car on a carpet. When the car rolls over the carpet, it doesn’t need any sticky tape, it just sticks for a little bit because of the way the carpet and the wheels are touching. That’s like physisorption! Tiny particles, like dust or gas molecules, can stick to surfaces like soil, paper, or even your skin, just by being close enough.

Think of the surface as a big net with lots of little strings. When tiny particles come near, they get caught in the net because of weak forces between them and the surface. These are called van der Waals forces, but you don’t need to remember that name, just know they're like invisible stringy fingers that help things stick together.

Physisorption is why your shoes sometimes feel sticky after walking on a hot road, or why some smells hang around in the air for a while. It’s not strong enough to keep things stuck forever, just long enough for you to notice!