4th grade Earth Science Part 2 L.O. I will describe what reshapes land and how this happens.

Day 1 Fast Changes in Earth Earthquakes *A fault is a crack in the Earth’s crust The two sides are called plates *During an earthquake, one of three things will happen: the plates push against each other and will slide along each other the plates push against each other and one side will go on top of the other the plates pull apart

The epicenter is where an earthquake is felt most strongly Tsunami is a very large ocean wave caused by an earthquake on the ocean floor

Volcanos Opening in Earth’s crust Hot ash, gases, and molten rock escape from deep within Earth Molten rock beneath Earth’s surface is called magma When magma reaches Earth’s surface, it is called lava *Hawaii was formed by volcanoes

*Landslides – the sudden movement of loose rock and soil down a steep slope The steeper the slope, the faster the soil and rock will move downhill *4 main things cause landslides: Heavy rains Sudden melting of snow Earthquakes Volcanic eruptions

Day 2 Slow changes in Earth *Weathering is when rocks slowly wear away into smaller and smaller pieces by water, snow, wind, and rain *Erosion moves these sediments (rock pieces) that were a result of weathering from one place to another

As moving water flows, it loosens and picks up the tiny particles that have been left by the weathering and carries it down stream or to other places – called erosion *Therefore, Moving Water causes landforms to erode *Wind carries bits of rock and soil in the air – so wind causes erosion *Moving water and wind cause erosion which created Grand Canyon

*5 things cause rocks to break into smaller pieces *The first three are the main causes *Continual freezing and thawing ice *Plant roots *Moving water Heat mixed with rain chemicals

Freezing and thawing Most rocks have tiny cracks in them Water gets into the cracks When it freezes, it expands Pushes the crack, making it a little bigger Melts Refreezes, pushing crack to make it bigger Eventually this process will cause the rock to break

Plant roots Roots are small and grow into cracks Over time, as the root grows it spreads the crack wider Eventually, the rock will break

Rocks that are exposed to or in moving water such as streams constantly bump against other rocks, wearing down sharp edges and becoming smooth and smaller