"The Formation of Pebbles" Changes in Ground Form PPT Courseware 2

Description

"The Formation of Pebbles" Changes in Ground Form PPT Courseware 2

Characteristics of pebbles: Pebbles, regardless of size, are shaped like bird eggs, smooth and round.

What are the characteristics of the rocks in the upper, middle and lower reaches of the river?

What is the pattern of the distribution of rocks?

Upstream: The rocks are very angular

Midstream: Medium in height, relatively smooth but not round.

Downstream: small, smooth and rounded surface

From upstream to downstream, the stones become smaller and smaller and rounder.

Explore

Loosening of mountains: The destructive effect of temperature differences on rocks.

Root swelling and cracking: The destructive effect of growing plant roots on rocks.

Mountain cracks: The destructive effect of water freezing on rocks.

Destructive effect on rocks

temperature change

water freezes

plant roots grow

summary

The long-term destructive effect on rocks caused by changes in temperature, water freezing, and plant roots growing is called weathering.

Experiment 1: Simulating the thermal expansion and contraction of rocks

How to heat rocks?

How to cool down rocks quickly?

Precautions

1. Use the outer flame of an alcohol lamp to heat.

2. Do not touch the stone directly with your hands, and do not keep your face too close when heating to avoid the stone exploding.

3. The stone should be heated and cooled repeatedly during the experiment.

experiment

Use a few small broken bricks to make the rocks in the upper reaches of the river become pebbles on the downstream river beach in a simulation experiment. Discuss the experimental results and conclusions.

summary

During the transportation of rocks by flowing water, there is friction between rocks, friction between rocks and the river bed, and friction between rocks and water. The rocks are subjected to this series of frictions, making the rocks smaller and smaller, and the edges and corners are gradually reduced. Round.

Experiment 2: Simulate the changes caused by stones being washed away by running water.

Think about the formation process of pebbles in comparison.

Where should the pebbles appear?

Could you please estimate and guess how pebbles are formed?

Summary: The formation process of pebbles

The first stage: Due to the weathering of the rocks on the mountains on both sides of the upper reaches of the river, many stones of different sizes are formed.

The second stage: These stones are washed by the flowing water, slowly move downstream, and are continuously rounded by the water flow. After a long period of time, it gradually turns into pebbles.

expand

What other phenomena have we seen that change the surface of the earth due to the action of flowing water?

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For more information about the PPT courseware "The Formation of Pebbles and Changes in the Ground Form", please click the "The Formation of Pebbles ppt and the Changes in the Ground Form" ppt tag.

"The Formation of Pebbles" Changes in the Earth's Surface PPT Courseware 2:

"The Formation of Pebbles" Changes in the Earth's Surface PPT Courseware 2 The Formation of Pebbles Have you ever seen pebbles? What do they look like? Observe the pictures and objects and talk about the characteristics of the pebbles. Characteristics of pebbles: Pebbles, regardless of size, are shaped like bird eggs, smooth and round. ... ..

"The Formation of Pebbles" Changes in the Earth's Surface PPT Courseware:

"The Formation of Pebbles" Changes in the Earth's Surface PPT Courseware Experiment 1: Simulating the Thermal Expansion and Contraction of Rocks How to heat rocks? How to cool down rocks quickly? What happened to the rocks? Weathering Changes in temperature: thermal expansion and contraction cause cracks in rocks. water..

"The Formation of Pebbles" PPT courseware on changes in ground form:

"The Formation of Pebbles" PPT courseware on changes in ground form. What is the name of the stone in the picture? What are the characteristics? Smooth Round What are the characteristics of the distribution of stones in rivers? The stone is large, with sharp edges and corners, and the surface is rough. The stone is large, with sharp edges and corners, and the surface is...

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Update Time: 2024-11-22

This template belongs to science courseware E-education edition sixth grade science volume 1 industry PPT template

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