Filtering

Sandy, salty water is poured through a filter. Does the paper catch the sand? Does the paper catch the salt?

The paper catches the sand, but the salt goes through.

The rule

Filtering — pouring a mixture through filter paper. The paper has holes too small to see.

Solid bits that are bigger than the holes get caught.

A dissolved solid is spread through the water in tiny pieces. The pieces are smaller than the holes, so they pass through. The paper cannot catch it.

Try the lab to finish this lesson.