6th grade Science Starter October 8th Changing Earth’s Surface: Today’s Benchmark: SC.6.E.6.2 Recognize that there are a variety of different landforms on Earth’s surface such as coastlines, dunes, rivers, mountains, glaciers, deltas, and lakes, and relate these landforms as they apply to Florida. -Learning Goal: Today the student’s will understand how glaciers form and move. -Students will be able to explain how glaciers cause erosion and deposition -Science Starter: Review 1. Describe How an Oxbow lake is formed. 2. Describe How a stream is formed.

On the Agenda Discuss Science Starter and Learning goal Finish 4.1 Water Erosion Today is Chapter 4, lesson 2: Glacial Erosion. As we go through the power point you may fill in your blank spaces, and draw the images into your booklets. Work on your booklets.

Groundwater Water that fills the cracks and spaces in underground soil and rock layers.

Groundwater can cause erosion through a process of chemical weathering.

Stalactite An icicle-like structure that hangs from the ceiling of a cavern.

Stalagmite A column-like form that grows upward from the floor of a cavern. Stalagmites in Carlsbad Caverns' Big Room

Karst topography A region in which a layer of limestone close to the surface creates deep valleys, caverns, and sinkholes. Sinkhole on Ocala, Fl farm

Karst Topography Why do you think karst topography occurs in these areas? Because the bedrock is made of layers of limestone. Name 3 states that you can find Karst Topography? Florida, Texas, Missouri

Key Questions How does moving water cause erosion? Moving water is the major agent of the erosion that has shaped Earth’s land surface. What land features are formed by water erosion and deposition? Valleys, waterfalls, flood plains, meanders, oxbow lakes, deltas, alluvial fans, caves

Glacial Erosion 4.2

Key Questions How do glaciers form and move? How do glaciers cause erosion and deposition?

Glacier Any large mass of ice that moves slowly over land.

Glaciers can form only in an area where more snow falls than melts. How do glaciers form? Glaciers can form only in an area where more snow falls than melts.

What makes Glaciers look blue? Refer to page 128 Glacial ice is denser than snow and it does not absorb the shorter blue light rays.

A glacier that covers much of a continent or large island. Continental glacier A glacier that covers much of a continent or large island. Continental glaciers can flow in all directions as they move.

Continental Glaciers today Presently Continental Glaciers cover 10% of Earth’s land. They cover Antarctica and most of Greenland.

Ice Ages Times in Earth’s history during which glaciers covered large parts of the surface. About 1 million years ago they covered about 1/3 of the earth. Most recently retreated about 10,000 years ago.

Valley glacier A long, narrow glacier that forms when snow and ice build up high in a mountain valley.

How do glaciers move? Continental glaciers can flow in all directions as they move.

Gravity constantly pulls a glacier downhill. How do glaciers move? Gravity constantly pulls a glacier downhill. Once the layer of snow and ice is about 30 meters deep- glacier begins to move.(About how many feet deep?) 30 Meters is about 100 Feet Deep Valley glaciers flow at a rate of a few centimeters to a few meters per day.

Glacial Erosion What did the glaciers do to the area?

How do glaciers cause erosion? The two processes by which glaciers erode the land are plucking and abrasion.

Plucking The process by which a glacier picks up rocks as it flows over the land. Many of the “plucked” rocks remain on the bottom and are dragged – gouging the bedrock. This is called abrasion. Plucking 

How do glaciers cause deposition? When a glacier melts, it deposits the sediment it eroded from the land, creating various landforms.

Till The mixture of sediments deposited directly on the surface by a glacier. Till is made up of many different sizes from clay  silt  sand  gravel boulders.

Moraine A ridge formed by the till deposited at the edge of a glacier.

Kettle A small depression that forms when a chunk of ice is left in glacial till.

Kettle Lakes

Glacial Landforms

Enhancement Glacial Overview: http://www.youtube.com/watch?v=duBas_Lkfh4

Glacier National Park http://www.glaciertrails.com/videos.php?act=play&vid=DTMOYQ Glacier Bay National Park Map http://www.nps.gov/common/commonspot/customcf/apps/maps/showmap.cfm?alphacode=glba&parkname=Glacier%20Bay