Why does Earth’s surface change? Today in Science Milestones Practice Question Changes to Earth’s Surface Notes Almost done with notes for the YEAR!!! Standard Essential Questions I can identify surface features on Earth caused by constructive and destructive processes. Why does Earth’s surface change?

Review… What are the layers of the Earth? Which layer do we live on? Why can we not live on the other layers? What are tectonic plates? What causes earthquakes to happen?

Review What is a fault? How are volcanoes formed? The islands of Hawaii are landforms created by __________________. What are tsunamis? What causes them to occur? What is a seismograph?

Continental Drift Theory The process of the continents slowly moving around on the surface of Earth. The surface of the Earth, including under the ocean, is made up of tectonic plates. The plates are sections of the surface of Earth, and some plates move towards or away from each other. Plates can also slide past each other.

Evidence to support the theory

Trenches Trenches can be found where faults are located under the ocean. Much smaller trenches are also caused by erosion. GLACIERS: very old sheets of ice the size of states that move along Earth’s surface, also create trenches as they slowly grind the surface.

Where are trenches found?

Ridges Ridges are formed when tectonic plates collide and both push up. This creates hills and mountains. Ridges and individual mountains are formed in areas where magma, or molten rock, from Earth’s core pushes up between or through tectonic plates. Stone mountain may be one of these magma-created mountains.

How were these ridges formed?

Weathering A slow destructive process where Earth’s materials such as rocks and soil are broken down into smaller parts. Weathering can also break down roads, buildings, and other materials humans make. Forces that cause weathering: wind, water, and ice (these forces also cause erosion).

Quiz! What are the three causes (agents) of weathering? Water Wind Ice

Mechanical Weathering The breaking of larger rocks into smaller pieces. Small pieces of rock = sediment Ice causes mechanical weathering when water gets into the cracks of rocks and freezes. When water turns to ice, it expands, or takes up more room. When this happens, rocks break apart. Moving air and water can also cause mechanical weathering. Blown sand or rushing water hits rocks, and the rocks get weaker over time and eventually crack or crumble.

Mechanical Weathering by Wind

Mechanical Weathering by Water

Mechanical Weathering by Ice

Mechanical Weathering Plants can cause mechanical weathering by sprouting and growing in soil that has collected in the cracks of a rock. As the plant grows, the roots extend and spread the crack until the rock eventually breaks

Quiz! What is mechanical weathering? What are some examples of mechanical weathering?

Chemical Weathering Water that contains acid can dissolve rocks. This water can trickle through the ground and can dissolve some rocks far under the surface. Caves are hollow spaces underground that are formed by chemical weathering.

Review What is erosion? What is deposition?

People, Critters, and Erosion Believe it or not people and animals are constantly eroding the earth around them. Often times it is just a little bit of dirt sliding off a walking path but other times it can lead to massive problems. During the Great Depression in the 1930's poor farming techniques helped cause what was known as the Dustbowl.

Quiz! How can people cause erosion? How can animals cause erosion?

Quiz! What is chemical weathering? What is an example of a landform that is created by chemical weathering?

Constructive vs. Destructive Processes These forces build up Earth’s surface. Caused by water, gravity, wind. What are some examples? These forces break down Earth’s surface. What are some examples? Can be slow or fast: Slow and destructive: erosion Fast and destructive: earthquakes

Quiz! What is a constructive force? What is a destructive force?

Constructive or Destructive? Delta

Constructive or Destructive? People breaking soil to plant crops.

Constructive or Destructive?

Constructive or Destructive? Sand Dunes

Constructive or Destructive?

Constructive or Destructive? Animals digging up soil and causing erosion

Constructive or Destructive? Formation of the Grand Canyon

Constructive or Destructive? Earthquakes

Constructive or Destructive? Weathering by wind Arches

Constructive or Destructive? Volcanoes

WED – create a diagram