"The Shape and Internal Structure of the Earth" PPT

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"The Shape and Internal Structure of the Earth" PPT

Part One: The Shape of the Earth

What does the earth look like?

The "Supreme Sky Theory" of the Western Zhou Dynasty - The sky is round and the place is round

"Book of Jin Astronomical Records" - "The sky is like a bamboo hat, and the earth is like a disk."

Ancient Indians believed that the earth was a round shield carried by three elephants, and the elephants stood on the back of a large turtle.

The ancient Babylonians believed that the earth was a hollow mountain, the continent was surrounded by sea water, and there was a huge round sky covering it.

The ancient Egyptians believed that the sky was supported by mountains and the stars hung down from the sky; the sun rode a small boat and followed a large river to various places.

The shape and internal structure of the earth PPT, part 2: exploration activities

Plan: Place the basketball and template at eye level. Point the pencil head vertically downward, move from A to B and from C to D, and observe the changes in the length of the pencil and the position of the pencil head.

What are the differences in the changes in the length and pencil tip position of a moving pencil on a basketball surface and a wooden board surface? Why is this so?

(1) When the pencil moves on the template, the length of the pencil you see changes _____ (fill in “yes” or “no”).

(2) When the pencil moves on the surface of the basketball, the pencil you see _____ (fill in the "pen tip" or "pen tail") disappears first, which is equivalent to the sailboat _____ (fill in the "mast" or "hull") that goes away on the coast. ”) disappear first, this means that the shape of the earth is _____.

The shape and internal structure of the earth PPT, part three content: class summary

Summary: The process of understanding that the earth is a sphere:

1. In the 6th century BC, the ancient Greek mathematician Pydacras first proposed the idea that the earth is spherical.

2. Aristotle observed a lunar eclipse and found that the shadow cast by the earth on the moon was arc-shaped, and he concluded that the earth was a sphere.

3. During the Portuguese navigator Magellan’s circumnavigation of the world in 1519, he used his own personal experience to prove that the earth is spherical.

4. Photos taken from space show that the Earth is an approximately spherical planet.

The shape and internal structure of the Earth PPT, Part 4: The size of the Earth

How big is the earth?

Equatorial radius: 6378 kilometers

Polar radius: 6357 kilometers

Equator circumference: 40,000 kilometers

The Earth is an ellipsoid slightly flattened at the poles and slightly bulging at the equator.

Thinking and calculating:

1. The circumference of the earth at the equator is about 40,000 kilometers. If the arms of middle school students are 1.5 meters long, how many middle school students are needed to hold hands and hug the earth?

2. If a person travels 50 kilometers a day, how many days will it take to circle the earth's equator?

The shape and internal structure of the earth PPT, Part 5: The internal structure of the earth

crust

mantle

Earth's core

What is the lithosphere made of?

The lithosphere is composed of the crust and the top of the mantle (above the asthenosphere)

Located 60~400km below the surface, it is mainly composed of molten magma material

The shape and internal structure of the Earth PPT, Part 6: Classroom exercises

1. The earth is a sphere with _______ at the poles and _______ at the equator.

2. Its equatorial radius is _______ kilometers. The poleward radius is _______ kilometers shorter than the equatorial radius. The Earth's equatorial circumference is approximately _______.

3. In the internal structure of the earth, the thinnest layer is _______, and the layer with the highest temperature is _________.

Keywords: Zhejiang Education Edition seventh grade science PPT courseware free download, PPT download of the shape and internal structure of the earth, .PPT format;

For more information about the "Shape and Internal Structure of the Earth" PPT courseware, please click the Shape and Internal Structure of the Earth ppt tag.

"The Shape and Internal Structure of the Earth" PPT download:

"The Shape and Internal Structure of the Earth" PPT download Part One: The Shape of the Earth What is the shape of the Earth? You describe it. The Earth is an approximately spherical planet. But what did the earth look like to people in ancient China? The sky is round...

"The Shape and Internal Structure of the Earth" PPT courseware:

The first part of the PPT courseware "The Shape and Internal Structure of the Earth": Understanding the shape of the earth: The ancient Indians in the Western Zhou Dynasty believed that the earth was a round shield, carried by three elephants, and the elephants Standing on the back of a big turtle again. in life..

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Update Time: 2024-09-19

This template belongs to science courseware Zhejiang Education Edition Seventh Grade Science Volume 1 industry PPT template

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