"Eyes and Glasses" Lenses and Their Applications PPT Courseware 2

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"Eyes and Glasses" Lenses and Their Applications PPT Courseware 2

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1. A convex lens has a ______ effect on light; a concave lens has a ______ effect on light.

2. Imaging rules of convex lens:

① When u>2f, a ____________ image is formed, and ______ is applied.

② When f＜u＜2f, a ____________ image is formed, and ______ is applied

③When u

Knowledge summary

1. The eyeball is like a camera. The lens and cornea work together to act as a convex lens (lens), and the retina acts as a film.

2. When looking at distant objects, the ciliary body relaxes and the lens becomes thinner. The light from the distant object just converges on the retina, and the eyeball can see the distant object clearly.

3. When looking at nearby objects, the ciliary body shrinks and the lens thickens. The light from the nearby objects just converges on the retina, and the eyeball can see the nearby objects clearly.

Causes of myopia

The cause of myopia is that the lens is too thick, the refractive power is too strong, or the eyeball is too long in the front-to-back direction, so the light from a distant point converges in front of the retina, and when it reaches the retina it is no longer a point but a blurry spot.

Causes of hyperopia

The cause of hyperopia is that the lens is too thin, the refractive power is too weak, or the eyeball is too short in the front-to-back direction, so the light from a little closer converges on the retina and forms a blurry spot on the retina.

Class exercise one:

1. Under normal circumstances, the image received on the retina looks like ______; after adding corrective glasses, the image received on the retina looks like _____. (Fill in "real" or "virtual")

2. Myopia can only see nearby objects. The possible reason is ( )

A. The lens is too thick; B. The lens is too thin; C. The image is behind the retina; D. The eyeball is too long.

3. The possible reason why hyperopia cannot see nearby objects clearly is ( )

A. The eyeball is too short; B. The lens is too thin; C. The image is in front of the retina; D. The image is in front of the retina.

Simple eye exercises

Step 1: Eye movement method - when the head rotates up, down, left and right, the eyes also move together.

Step 2: Blinking method - tilt your head back and blink continuously to make the blood flow smoothly. When your eyes are slightly tired, just blink 2-3 times.

Step 3: Eye gymnastics - point your middle finger between the eye socket and the bridge of the nose, cover your face with your palm and rub it back and forth for five minutes. Then slowly move the neck to the left and right, then close your eyes, make a fist and tap the back of the neck ten times.

Step 4: Look far and near - look at the distance for three minutes, then look at your palms for 1-2 minutes, and then look at the distance again. This exchange of distance and distance several times can effectively eliminate eye fatigue. Try it!

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For more information about the PPT courseware "Lens and Its Applications in Eyes and Glasses", please click the "Lens and Its Applications ppt Eyes and Glasses ppt" tag.

"Eyes and Glasses" Lenses and Their Applications PPT Courseware 8:

"Eyes and Glasses" Lenses and Their Applications PPT Courseware 8 Learning Objectives 1. What are the main parts of the human eye? 2. How do human eyes see objects? 3. How does the human eye see objects at different distances? 4. What indicates the refractive power of a lens? 5. The formation of myopia..

"Eyes and Glasses" Lenses and Their Applications PPT Courseware 7:

"Eyes and Glasses" Lenses and Their Applications PPT Courseware 7 Think about what you know about your eyes. How do the eyes see these objects? 1. Eyes 1. Structure of the eyeball (1) Lens and cornea: the combined effect is equivalent to A convex lens (2) retina: quite...

"Eyes and Glasses" Lenses and Their Applications PPT Courseware 6:

"Eye and Glasses" Lens and Its Application PPT Courseware 6 Learning Objectives: 1. Understand the structure of the eyeball and how the eye sees objects clearly. 2. Understand the causes of myopia and hyperopia, and know how to correct myopia and hyperopia. 3. Understand the common sense of eye protection. ..

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Update Time: 2024-10-20

This template belongs to Physics courseware People's Education Edition Physics for Grade 8, Volume 1 industry PPT template

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