"How Light Spreads" Light PPT Courseware 5

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"How Light Spreads" Light PPT Courseware 5

Key points from the previous section:

1. The direction of the shadow of an object under sunlight changes with the change of the direction of the sun. The shadow is always opposite to the direction of the sun.

2. The length of the shadow of an object under sunlight changes with the position of the sun in the sky. When the sun is at its highest position, the shadow is the shortest, and when the sun is at the lowest position, the shadow is the longest.

1. How does light spread?

2. What is the speed of light propagation?

3. How many minutes does it take for light to reach the earth from the sun?

judge

1. The speed of light is much faster than the speed of sound. ( )

2. Light can propagate in a curved form. ( )

3. Shadows are always on the back of objects. ( )

4. The speed of light is 30 kilometers per second. ( )

1. Light propagates in the air in the form of ( ).

A. Curve B. Straight line C. Wavy line

2. The speed of light propagating in the air is ( ) per second.

A. 30 kilometers B. 300,000 kilometers C. 3 million kilometers

3. Which of the following examples cannot be explained by light propagating in a straight line ( ).

A. Solar and lunar eclipses B. The formation of shadows C. See lightning first and then hear thunder

4. It takes about ( ) for sunlight to reach the earth.

A. 8 seconds B. 8 minutes C. 8 hours

5. The circular "light spots" formed on the ground in the woods are ( ).

A. The shadow of the leaves B. The image of the sun C. The image of the gap between the leaves

6. The idea that "light propagates in a straight line" cannot be supported ( ).

A. The light emitted by car lights at night B. The words on the book can be seen during the day

C. The light from the spotlights in the ballroom

7. The following analysis of the reason why objects produce shadows is correct ( ).

A. When light propagates, when it encounters an opaque object, part of the light will be blocked, and there will be a dark area on the backlit surface of the object, which is a shadow.

B. When light propagates, when it encounters a transparent object, part of the light will be blocked, and there will be a dark area on the backlit surface of the object, which is a shadow.

C, A and B are all correct

Other examples proving that light travels in straight lines

1. Use a flashlight to shine into the sky at night, and you can see a straight beam of light.

2. Using a laser pointer, you can see the linear propagation of light.

3. Use a straw and look at the light through the straw. If it is straight, you can see it, but if it is bent, you cannot see the light. These all show that light propagates in straight lines.

Key points of this section:

Light travels in straight lines

The speed of light propagation is 300,000 kilometers per second.

It takes 8 minutes for light from the sun to reach the earth.

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For more information about the PPT courseware "How Light Spreads", please click the ppt tag of "How Light Spreads".

"How Light Spreads" Light PPT Download:

"How Light Spreads" Light PPT Download Part One Content: Introduction to the New Lesson In the early morning, the sun comes out and the room is filled with sunlight; at night, you turn on the flashlight and the light illuminates the road ahead. When light illuminates objects around us, have we ever thought about where it comes from and...

"How Light Spreads" Light PPT:

"How Light Spreads" Light PPT Part One Content: Experimental Exploration Exploration Content: 1. How does light propagate? 2. How are shadows formed? Light propagates dispersedly. Light propagates in a straight line. Light propagates in all directions... How does light propagate...

"How Light Spreads" Light PPT Courseware 4:

"How Light Propagates" Light PPT Courseware 4 Teaching Objectives and Requirements 1. Be able to illustrate and explain that light propagates in a straight line; 2. Experience designing and verifying experiments of straight-line propagation of light; 3. Use the propagation laws of light to explain the generation of shadows s reason. How does light hit objects?

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Update Time: 2024-11-22

This template belongs to science courseware Fifth Grade Science Volume 1, Textbook Edition industry PPT template

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