The Force of Moving Water Click to see

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The Force of Moving Water (Click to see movie. )

The Force of Moving Water (Click to see movie. )

9. 3 The Force of Moving Water KEY CONCEPTS: • What enables water to

9. 3 The Force of Moving Water KEY CONCEPTS: • What enables water to do work? • How does sediment enter rivers and streams? • What factors affect a river’s ability to erode and carry • sediment? • KEY TERMS: energy kinetic energy load friction potential energy abrasion turbulence

A river’s water has energy. Energy is? The ability to do work or cause

A river’s water has energy. Energy is? The ability to do work or cause change. potential _____ energy Potential energy is energy that is stored and waiting to be used later. kinetic energy _____ Kinetic energy is the energy an object has due to its motion. Merrimack River in NH and MA

How Water Erodes Gravity causes the movement of water across the Earth’s land surface.

How Water Erodes Gravity causes the movement of water across the Earth’s land surface. In the process of water erosion, water picks up and moves sediment. Sediment includes soil, rock, clay, and sand. How does sediment enter a river? Most sediment washes or falls into a river as a result of mass movement and runoff. Other sediment erodes from bottom or sides of the river. Wind may also drop sediment into the water. Rivers also obtain sediment from abrasion. Abrasion is the wearing away of rock by a grinding action.

How Water Erodes (Cont’d) The amount of sediment that a river carries is its

How Water Erodes (Cont’d) The amount of sediment that a river carries is its _____. load Gravity and the force of moving water cause the sediment load to move downstream. Large sediment falls to bottom and moves by rolling and sliding. Smaller sediment is lifted and carried downstream. Water dissolves some sediment Completely. The sediment carries these dissolved sediments in solution. *A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution. The most common solvent in everyday life is water.

Erosion and Sediment Load The power of a river to cause erosion and carry

Erosion and Sediment Load The power of a river to cause erosion and carry sediment depends on several factors: • Slope • Volume These all affect how fast the river flows And how much sediment it can erode. • Shape Slope is the amount the river drops toward sea level over a given distance. As more water flows through a river, its speed Increases.

Erosion and Sediment Load (Cont’d) A streambed’s shape affects the amount of friction between

Erosion and Sediment Load (Cont’d) A streambed’s shape affects the amount of friction between the water and the streambed. Friction is the force that opposes the motion of one surface as it moves across another. A deeper river with less water coming in contact with the streambed has less friction than a shallower river. A river full of boulders and other obstacles will have a lot of friction. This roughness increases friction and slows down the river. Instead of moving downsteam, the water moves every which way called turbulence _____.

Hoover Dam How Hydroelectric Power Works (Click)

Hoover Dam How Hydroelectric Power Works (Click)

The Power of Water (Click to see movie about a renewable energy source. )

The Power of Water (Click to see movie about a renewable energy source. ) H 2 O HHO (Click)

Last Night’s Homework – 9. 3 The Force of Moving Water Assessment: 1. a.

Last Night’s Homework – 9. 3 The Force of Moving Water Assessment: 1. a. What is energy? It is the ability to do work or cause change. b. How is a river’s potential energy changed into kinetic energy? Gravity causes river water to move down a slope. As the water flows, its potential energy changes to kinetic energy. c. What are two effects produced by flowing water in a river? They are erosion and deposition. 2. a. What are the two main sources of sediment that rivers and streams carry? The two sources are mass movement and runoff.

Assessment (Cont’d) 2. b. Describe a process by which a stream can erode its

Assessment (Cont’d) 2. b. Describe a process by which a stream can erode its streambed. Sand other sediment grains can strike the rock of the stream’s bed and wear it away. This process is abrasion. c. Near a stream’s source, a stream erodes a piece of rock from its streambed. As the rock is carried down the stream, how will its size and shape change? Explain. The piece of rock will become smaller and more rounded. 3. a. What 3 factors affect how fast a river flows? Slope, volume of flow, and shape of the stream bed. b. Study Fig. 17. Over time, what will happen to the river’s bank at B? Why? The river’s bank will eventually erode, and the curve will become larger.