How Does Wind and Water Change the Land?

Now imagine a whole beach after a big storm. The waves crash over and over. The wind blows and blows. When the storm is over, the beach looks different. Some sand is gone. New sand piles are in other spots. The shape of the land has changed!

The ground under your feet is called land. Land can be flat, hilly, rocky, or sandy. Did you know that wind and water can slowly change the shape of the land? Let's find out how!

Scientists learn by watching things carefully and trying simple tests. You can be a scientist too! Let's do a simple test to see how water changes land.

What you need:

• A small pile of sand or dirt (outside or in a pan)
• A cup of water
• Your eyes to observe!

What to do:

• Make a small hill out of sand or dirt.
• Look at your hill carefully. What shape is it?
• Slowly pour the cup of water over the top of the hill.
• Watch what happens! Where does the sand or dirt go?

What you might see: The water will make little paths down the hill. It will carry sand and dirt to the bottom. Your hill will get smaller. The sand piles up at the bottom!

When we poured water on our dirt hill, we saw water carry dirt from the top to the bottom. The hill got smaller! The dirt piled up in a new spot. This is just what happens in nature.

Rain washes dirt off hills and mountains. Rivers carry sand and rocks downstream. Ocean waves crash onto cliffs and slowly break them apart. Wind blows sand across deserts and makes new sand dunes.

Look at this: water and wind don't just take land away. They also drop it off somewhere new. A river carries sand downstream and drops it. Over time, new land builds up where the sand drops! Scientists call this deposition (say: deh-puh-ZIH-shun). It means setting something down in a new place.

Let's think about something cool. When you push a toy car, it moves. When you push it harder, it moves farther. The same thing happens with wind and water!

When wind or water is stronger, it changes the land more. When it is weaker, it changes the land less. This is a pattern called cause and effect. One thing (the cause) makes something else happen (the effect).

Do you see the pattern? A bigger cause makes a bigger effect! This pattern shows up everywhere in science, not just with land. A harder push makes a ball roll faster. More heat makes water boil sooner. Scientists look for these patterns to understand how the world works.

Now that you know wind and water can change the land, guess what? People use this science to solve problems!

Sometimes we don't want water to wash away land. For example, waves might wash away a beach near people's homes. That could be dangerous! So people think of ways to slow down erosion.

• Erosion — When wind or water carries bits of land (like dirt, sand, or rocks) away to a new place.
• Deposition — When dirt, sand, or rocks are set down in a new place by wind or water.
• Weathering — When wind, water, or ice slowly breaks rocks into smaller pieces.
• Landform — A shape of land, like a hill, valley, mountain, or beach.
• Cause and Effect — When one thing (the cause) makes something else happen (the effect).