"Light World Tour" Light and Eyes PPT Courseware

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"Light World Tour" Light and Eyes PPT Courseware

teaching objectives

1. Understand the role of light and know that light is closely related to humans.

2. Knowing that light propagates along a straight line in the same uniform medium, we can use the law of straight line propagation of light to explain the phenomenon of shadow formation.

3. Know that light propagates at different speeds in different media, and remember the speed of light in vacuum.

4. Understand the composition of white light and the phenomenon of mixing different colors of light, and know the three primary colors of light.

5. Be able to use light to describe the propagation path and direction of light, and learn to use diagrams to analyze optical phenomena such as the causes of shadows.

6. Experience the process of decomposing sunlight into seven colors of light, and realize from the dispersion phenomenon that white light is complex color light.

The course standard requirements for this chapter:

1. Know the speed of light propagation in vacuum.

2. Through experiments, explore and understand the law of light reflection, explore and understand the refraction phenomenon and its characteristics of light.

3. Through experiments, explore the relationship between the image and the object when the plane mirror is used for imaging; know the characteristics and applications of the plane mirror imaging.

4. Understand the convergence effect of convex lenses and the divergence effect of concave lenses. Explore and understand the rules of imaging by convex lenses. Understand the application of the imaging laws of convex lenses.

5. Through experiments, understand the composition of white light and the phenomenon of mixing different colors of light.

1. What light can do for us

Students answer: Can you name some other uses of light?

What is light?

Research shows that light is an electromagnetic wave. Electromagnetic waves are a huge family. The light we usually see is called "visible light", which generally refers to electromagnetic waves that can cause human vision. It is only a small part of the electromagnetic wave family.

Information Express:

1. Light source: An object that can emit light by itself is called a light source.

2. Substances that can transmit light, such as air, water, glass, etc., are usually called light media.

2. Straight-line propagation of light: Light propagates along straight lines in the same homogeneous medium.

3. How to describe the propagation of light?

Light: Use a straight line with an arrow to vividly describe the propagation path and direction of light (straight line - path, arrow - direction)

Note: Light does not actually exist. It is an ideal model introduced to describe the propagation of light.

summary:

1. Light propagates along straight lines in a uniform medium.

2. Examples proving that light propagates along straight lines in a uniform medium:

1. The formation of shadow. 2. Solar and lunar eclipses.

3. Laser alignment. 4. "Three points and one line" when shooting and aiming, etc.

3. Speed ​​of light

1. The fastest light propagation speed in vacuum is 3×108m/s

2. Generally: V gas>V liquid>V solid

1. Color of opaque objects

The color of an opaque object is determined by the colored light it reflects. That is, it reflects light of the same color as itself and absorbs other colored lights.

2. Color of transparent objects

The color of a transparent object is determined by the colored light it transmits. That is, it lets light of the same color as itself pass through and absorbs light of other colors.

Important conclusions:

Black absorbs all colored light

White reflects all colors of light

Colorless transparent glass transmits all colors of light

Practice in class:

1. In the absence of other light sources, the blue light emitted by the stage spotlight shines on the actor wearing a red top and white skirt. The audience sees ( )

A. The whole body is blue

B. The top is purple and the skirt is white

C. The top is black and the skirt is blue

D. The top is black and the skirt is white

2: Make the following observations through blue light-transmitting glass, the result is ( )

A. If you observe a yellow object, you can see green

B. Observe green objects and you can see yellow

C. If you observe red objects, you can see black

D. If you observe any color object, you will see blue.

3: Write blue words on white paper and see them under blue light ( )

A. The paper is white and the words cannot be seen clearly.

B. The paper is white and the words can be read clearly.

C. The paper is blue and the words are black, so you can see them clearly.

D. The paper is blue and the writing is also blue, so you can’t see it clearly.

Operation:

Classwork: Questions 2, 3, 4, and 5 on page p50.

Tutorial (preview):

a. Exchange examples of light reflection phenomena in life? Understand the reflection of light, reflected light, incident light, reflection angle, and incident angle; memorize and understand the laws of light reflection. Understand that light paths are reversible.

b. What is specular reflection? What is diffuse reflection? What's the difference between the two? Give examples of specular reflection and diffuse reflection in life.

c. Application examples of light reflection. Ruby laser, optical fiber, satellite remote sensing, GPS positioning, glass curtain wall reflection

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For more information about the "Light and Eyes World Tour of Light" PPT courseware, please click the "Light and Eyes ppt Light World Tour ppt" tag.

"Light World Tour" Light and Eyes PPT Courseware 2:

"Light World Tour" Light and Eyes PPT Courseware 2 Learning Objectives 1. Know some uses of light, know that light is closely related to human life 2. Know that light propagates along straight lines in the same homogeneous medium, and can be used to explain the formation of shadows Phenomenon 3. Understand the propagation of light in vacuum..

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Update Time: 2024-09-08

This template belongs to Physics courseware Guangdong and Shanghai version of eighth grade physics volume one industry PPT template

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