"The Secret of the Rainbow" PPT courseware

Description

"The Secret of the Rainbow" PPT courseware

Part One: Teaching Objectives

By understanding the causes of rainbows, students will know that sunlight is composed of seven different colors of light.

Cultivate students' reasoning ability (inferring the cause of rainbows based on dispersion experiments) and experimental abilities (initially learning to use a prism to conduct light dispersion experiments)

Guess the cause of rainbow formation

Use a prism to do the dispersion experiment of light:

Experimental requirements:

For each group of 4 people, the team leader designates people to go to the material supermarket to select the required materials and make experimental records.

Kind tips:

1. The team leader shall do a good job in the division of labor in the experiment;

2. Use experimental materials with care, handle them with care, and protect yourself as well as the experimental supplies;

3. Arrange and put them back to their original places after use.

The Secret of the Rainbow PPT, Part 2: Making a Rainbow

Let’s make a rainbow too, shall we?

Experimental requirements:

For each group of 10 people, choose one person to spray, one person will record the experiment, and the others will watch the relationship between the size of the water droplets and the formation of the rainbow.

Kind tips:

1. The team leader shall do a good job in the division of labor in the experiment;

2. Do not spray the sprayer at people;

3. Spray with your back to the sun, and pay attention to the wind direction to prevent the mist from being blown by the wind;

4. When spraying, everyone in the group should go behind the demonstrator and choose a suitable angle to watch, so as not to wet their clothes.

The Secret of the Rainbow PPT, Part 3: Why is the rainbow curved?

Reason one: related to the wavelength of light

The wavelength of light determines how much light is bent. Originally, light travels in a straight line. Once it enters the water, it is refracted. All the small water droplets in the sky are arranged in a circle. When the relative positions of the water droplets on the circle, the sun, and the human eye are the same, the colored light refracted from the water droplets can be projected into the human eye. The degree to which light bends as it passes through a water droplet depends on the wavelength (i.e., color) of the light—red light bends the most, followed by orange and yellow light, and so on, with violet light bending the least. So each color appears in a different location in the sky.

Reason 2: It has a lot to do with the shape of the earth

Because the Earth's surface is a curved surface and is covered by a thick atmosphere, the water content in the air after a rain is higher than usual, causing refraction when sunlight strikes small water droplets in the air. At the same time, because the atmosphere on the earth's surface is an arc, sunlight is refracted on the surface to form the arc-shaped rainbow we see.

The Secret of the Rainbow PPT, Part 4: Consolidation Practice

do you know?

(1) Is sunlight a monochromatic light? What colors of light does it consist of?

(2) What instrument can be used to disperse sunlight into seven colors of light?

(3) How is a rainbow formed?

(4) Think about it, rainbows generally don’t appear in the sky for a long time. Why is this?

Improvement after class:

The natural world is mysterious and unpredictable, and there are still many unknown secrets waiting for us to discover and explore. I hope you will observe more and think more, use weekends, holidays, etc. to boldly explore natural phenomena, and keep records, and return to school to talk to your teacher Share and communicate with classmates. There will be scientists in our class who are as accomplished as Darwin and Newton.

Keywords: Qingdao edition fourth grade science PPT courseware for the second volume free download, The Secret of the Rainbow PPT download, .PPT format;

For more information about the "Secret of the Rainbow" PPT courseware, please click the "Secret of the Rainbow ppt" tab.

"The Secret of the Rainbow" PPT:

"Secret of the Rainbow" PPT Part 1 content: The timing of rainbow appearance: After rain, next to fountain, next to water, next to waterfall. What factors may be related to the appearance of rainbow? Sunlight and water droplets. Let's do a simulation experiment below. Experiment requirements: Every 10 Get into a group and choose...

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Update Time: 2024-09-07

This template belongs to science courseware Qingdao Edition Fourth Grade Science Volume 2 industry PPT template

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