Presentation on theme: "Chapter 1 Unit C Changes to Earth’s Surface. Lesson 1 Changes to Earth’s Surface Landforms: - physical features on Earth’s surface. Glaciers Mountains."— Presentation transcript:
Chapter 1 Unit C Changes to Earth’s Surface
Lesson 1 Changes to Earth’s Surface Landforms: - physical features on Earth’s surface. Glaciers Mountains Valleys Beaches Canyons Plains What forms these different landforms? Water Wind Ice Mass Movement
Water Weathering – is the process of breaking rock into silt, clay, sand or other tiny pieces called sediment. Erosion – the process of moving sediment from one place to another. Deposition – the process of dropping or depositing sediment in a new location. Water can carve canyons, waves can erode beaches and cliffs. Water can break rocks into smaller pieces and move them to a new place. This can be done through rivers, oceans, streams, etc.
Wind Wind can move sediment from one place to another. It can erode a lot of sediment. Wind erosion can create arches, columns, dunes, and rocks that look like tables
Ice Glaciers- are thick sheets of ice, formed in areas where more snow falls during the winter than melts during the summers. There are two kinds of glaciers: 1.Valley Glaciers – are found high in mountain valleys, creating U – shaped valleys 2.Continental glaciers – are ice sheets that cover larger areas of the Earth’s surface. Ex: Greenland & Antarctica
Mass Movement Mass Movement- is the downhill movement of rock and soil because of gravity. Mudslides and landslides occur quickly and change landforms suddenly. Creep is when soil moves slowly down hill over time due to gravity. Sinkholes are a large hole in the ground that appears suddenly, after the ground underneath it has become weak. ayer.aspx?itemnum= ayer.aspx?itemnum=187 6
Review Questions 1.What is erosion? 2.What is deposition? 3.What forces cause erosion and deposition? 4.Why is weathering so important to life on land? 5.A type of mass movement is? a)Glacier b)Delta c)Mudslide d)Terminal moraine
Earth’s Interior Earth has three distinct layers. Crust – is the outer later and it is made of rock. Mantle – is the layer of rock just below the crust. It is soft like melted candy. Core – is the center of the Earth. It is very hot and contains 2 parts: Outer core – molten rock Inner core – solid iron
We’re Moving? Earth’s surface is always moving. Plates – are rigid blocks of crust and upper mantle rock. There are twelve major plates that fit together like puzzle pieces. They float on the soft rock of the mantle.
Mountains Mountains form when Earth’s crust folds, cracks, and bends upward because of plate movement. The highest mountains form where plates collide. Ex: Himalayas Mountain don’t just form at plate boundaries. They can form wherever pressure is great enough to push rock upward. Mountains form in the ocean too! Where plate pull apart Magma builds up and form underwater mountain chains.
Volcanoes Volcano – is a mountain formed by lava and ash. Magma – is molten rock from Earth’s mantle. Lava – is magma that reaches Earth’s surface. Ash – is small pieces of hardened lava.
Volcanoes continued…. Three Types of Volcanoes Shield Volcano – are broad with gentle slopes. They are mostly lava. Cinder Cone Volcano – are tall and narrow with steep slopes. They are mostly ash. Composite Volcano – are wide and have fairly steep slopes. They are lava & ash. Mauna Loa is the largest volcano in the world; it is a shield volcano
Volcanoes continued… Cinder Cone VolcanoRing of Fire
Earthquakes An earthquake – is a shaking of the ground caused by the sudden release of energy in Earth’s crust. It occurs due to a sudden release of energy in Earth’s crust. The energy comes from; plates crushing together, scraping past each other or bending along jagged boundaries. Faults – breaks in Earth’s plates where pieces of crust move.
How are Earthquakes measured? Earthquakes send out energy in the form of seismic waves. The intensity of these waves are measured using a seismic graph. Strength of earthquakes is measured on a Richter scale from The worst recorded Earthquake was in Chile May 22, 1960 with a magnitude of 9.5
Review Questions 1.Describe three ways in which Earth’s plates interact. 2.What is magma and where does it comes from? 3.How do volcanoes form where oceanic and continental plates collide? 4.Assume that the overall size of Earth’s crust stays the same. If one plate is pushing away from the plate next to it on one side, what must be happening at the boundary with another plate on the opposite side? 5.Many strong earthquakes are caused by? a)Plates sliding past each other b)Lava flowing down the side of a volcano c)Plates spreading apart d)Hot magma
Chapter 1 Lesson 3 How Earth’s Surface Has Changed
Continental Drift Continental drift- is the theory of how Earth’s continents move over it’s surface. 225 million years ago Earth was one supercontinent called Pangea.
What do you predict Earth will look like 200 million years from now? The Atlantic Ocean is getting wider pulling North America and Europe farther apart. The Pacific Ocean is getting smaller. Australia is moving North.
Fossils Fossils – are the remains or traces of past life found in some rocks. Scientists study fossil to find out how life has changed on Earth. Most fossils are not the actual remains of the organisms but traces left behind after they have dissolved or decayed.
Review Questions 1.What was Pangea? 2.How old are the oldest rocks of the Grand Canyon? 3.How do we know that Earth’s life was different in the past? 4.Why is the Grand Canyon important to scientists studying Earth’s past? 5.The Southern continent that existed 200 million years ago was called? a)Gondawana b)Precambria c)Laurasia d)Eurasia