How Weather Changes Earth's Surface

Weather is more than just rain or sunshine. Weather can slowly change the land you walk on every day! Forces like wind, rain, ice, and heat work together to shape Earth's surface over time.

You will discover that weather moves soil, breaks rocks, and even carves out valleys and canyons. These changes happen slowly, but they are very powerful.

Weathering is when weather slowly breaks rocks into smaller and smaller pieces. Rain, wind, ice, and temperature changes all cause weathering.

One important type is called freeze-thaw weathering. When water gets into tiny cracks in a rock and freezes, it expands and pushes the crack wider. Over many years, this breaks the rock apart into smaller pieces.

The sun also causes weathering. When rocks heat up during the day and cool down at night, they slowly crack over time.

Erosion happens when wind or water picks up soil and rocks and carries them to a new place. This is one of the biggest ways weather changes Earth's surface.

When it rains very hard, water flows quickly over the ground and washes soil downhill. This is called runoff. Wind can also pick up loose, dry soil and blow it far away, especially during a drought.

On a sandy beach, strong winds blow sand grains to new spots, changing the shape of the beach. In deserts, wind piles sand into hills called sand dunes, which slowly move as the wind blows.

After erosion moves soil and rocks, they have to land somewhere. Deposition is when moving water slows down and drops the soil, sand, or rocks it was carrying in a new location.

For example, when a river floods, it carries sediment onto nearby land. When the water slows down, it deposits that sediment, sometimes making the soil very rich and fertile.

Different weather events change Earth's surface in different ways. Here is what you should know about each one:

• Flood: A flood covers land with too much water and washes away soil. It can also deposit new soil in flat areas near rivers.
• Drought: A drought happens when there is very little rain for a long time. The soil dries out, cracks, and becomes easy for wind to blow away.
• Hail: Hail drops balls of ice from storm clouds. Hailstones can dent or crack the ground and damage plants and crops.
• Blizzard: A blizzard piles up heavy snow that presses down on the ground. A thick layer of snow can also act like a blanket, keeping soil from freezing solid underneath.
• Storm Surge: A storm surge pushes ocean water onto shore, eroding beaches and washing away sand.
• Hurricane: A hurricane brings huge waves and powerful winds that wash away the shore and change the shape of coastlines.
• Tornado: A tornado has powerful spinning winds that can rip up trees, strip soil, and carry rocks and debris far away.
• Landslide or Mudslide: Very heavy rainfall soaks into hillside soil, making it heavy and slippery. This can cause soil and rocks to slide suddenly downhill.

Plant roots act like anchors that hold soil in place. When a hillside has no plants, heavy rain can easily wash the bare soil away.

This is why planting trees and grass is so important for preventing erosion. You can think of plant roots as nature's way of protecting the ground.

Erosion: Erosion is when wind or water picks up soil and rocks and moves them to a new place. For example, wind blowing sand from a beach to a new spot is erosion.

Weathering: Weathering is how weather slowly breaks rocks into smaller and smaller pieces over a very long time. Rain, ice, wind, and temperature changes all cause weathering.

Sediment: Sediment is the tiny pieces of rock and dirt that get moved by wind or water. When a river slows down, it drops its sediment in a new place.

Runoff: Runoff is water that flows across the ground after it rains. As runoff moves, it picks up soil and carries it downhill.

Deposition: Deposition happens when moving water slows down and drops the soil, sand, or rocks it was carrying in a new location. River deltas are built by deposition.

Flood: A flood happens when too much water covers land that is usually dry. Floods can wash away soil and deposit new sediment in flat areas.

Drought: A drought is a long period of time with very little or no rain. During a drought, soil dries out and cracks, making it easy for wind to blow it away.

Hail: Hail is balls of ice that fall from storm clouds. Hail can damage plants, crops, and even crack the ground.

Blizzard: A blizzard is a very heavy snowstorm with strong winds. The heavy snow from a blizzard presses down on the ground and can pile up very deep.

Storm Surge: A storm surge is when a powerful storm pushes ocean water onto the shore. Storm surges erode beaches by washing sand away.

Sand Dunes: Sand dunes are hills of sand that wind builds up in deserts or on beaches. Wind slowly moves sand dunes from one place to another.

Glacier: A glacier is a massive, slow-moving sheet of ice. As a glacier moves, it scrapes and carves the land beneath it, creating valleys.

You can look outside after a rainstorm and see erosion in action. Notice if any soil has washed away from a garden or hillside. Can you spot where the soil was deposited?

You can also think about how different weather events change the land. Ask yourself: What would happen to a sandy beach after a big storm? What would happen to dry soil during a long drought?

Practicing these ideas will help you answer questions about how weather shapes Earth's surface over time.

To understand how weather affects Earth's surface, it helps to already know what different types of weather are. Knowing about rain, wind, snow, and ice gives you a strong starting point.

As you learn more about weather and Earth's surface, you will start to see how the land around you is always slowly changing. Every rainstorm, every windy day, and every cold winter is shaping the Earth a little bit at a time.

This topic is part of your study of Weather. As you explore how weather changes Earth's surface, you are building important science skills that connect to many other ideas in science.

Understanding erosion, weathering, and deposition helps you see how rivers, valleys, canyons, and beaches are formed over long periods of time. These are all connected to the big idea that Earth's surface is always slowly changing because of weather.

You are also building knowledge about the water cycle, since runoff and flooding are important parts of how water moves across the land. Keep exploring weather and Earth science to discover even more amazing connections!