Once all these pores are filled with water, the sand is saturated, which means that the sand cannot take up any more water. It doesn't actually disappear-it drains into the tiny pores between the grains. If you pour water on the sand, the water seems to disappear into the sand. There are many pores between all the sand particles at the beach. (Think about how a pile of larger rocks has similar spaces between them.) These spaces are called pores. Even when sand particles appear to be directly touching each other, because they are irregularly shaped, there are tiny spaces in between them.

Materials such as sand that are made of many separate tiny particles are called granular materials. Many beaches are made of sand, which comes from-rocks that have been ground into tiny particles by water and wind. You will find out exactly how this happens by trying this beachy activity!

Why is that? These dry footprints are caused by the pressure of your feet. While doing that, have you ever looked at your footprints in the wet sand? If so, you might have noticed that with every step it looks like the sand around your feet dries out.

Summer is a nice time to take a stroll at the beach and walk barefoot along the shoreline.

How water moves through a sponge