Weathering & Erosion

Before Video

• The object breaks down into smaller pieces. It physically changes which can be noticed by is shape, texture and other features.

• Erosion is the process of moving material like sand and rocks from one location to another.

• Rain can change earth’s surface. It can soften land, which can make the land easier to crumble and erode away. The sunlight during the summer can cause surfaces to expand and contract. This can cause cracks to form in those surfaces.

• When water freezes it expands! If water is in a container and allowed to freeze it can either change the shape of that container after expanding or crack the container.

• The sand will act like sandpaper and scrape the rock. If this continues to happen, the surface of the rock will change. Over a long time period (thousands or millions of years) the changes to the rock can be dramatic.

After Video

• Split Apple Rock was formed by weathering from ice! When water gets into a small space and freezes, it expands and can crack whatever is containing it (just like the metal pipe in the video.)

• Izzy mentioned that cracks in the sidewalk formed because the concrete expanded and contracted over time. When the sun heated the sidewalk it caused the concrete to expand. At night the sidewalk cools and the surface contracts. Since this happened many times, the sidewalk eventually cracked. It’s like bending something over and over again – eventually it breaks!

• Wind carried sand particles close to the surface and they hit the bottom of the rock more than the top. Since the bottom is carved more it looks like a mushroom.

• Water, wind, freezing and gravity.

• Sometimes weathering happens really fast while at other times it happens very slowly. The amount of time is mostly due to the properties of the rock that is experiencing weathering. For example, soft surfaces like soil will weather really fast but hard surfaces like rock take longer.

• Deposition means that small pieces of the Earth are deposited, or end up somewhere else. In order for something to end us somewhere else it first has to be moved – that’s erosion!