Light Blog 9

CLASS 8 CHAPTER 16
Light
Day 9


Dear Learners,

In the previous blog, we have learned about light and reflection of light. Let me help you to recall few important points

1. Dispersion of light.
2. Spectrum of light.
3. Formation of rainbow.
Today, we will be learning about one of most important sense organ that is EYE

Happy Learning!😊

At the end of it, you will be able to:
1. explain the parts of eyes.
2. tell the functions of various parts of eye.
3. draw the diagram of internal parts of the human eyes.
But, before we start the chapter you all should read page no 258, 259 of your text book. By doing this, it will be easier for you all understand the topic well.

So, lets start the topic.........


THE HUMAN EYE- WHAT IS INSIDE OUR EYES.

Click on the link to get the idea:


EXPLANATION

The eye is a most important sense organ. Eyes resembles a camera in many ways. The main parts of the eye are shown in figure of your text book page 258.

Let us study the parts of human eye:

1. CORNEA: It is a transparent spherical membrane in front of the eye. Light enters the eye through cornea.

2. IRIS and PUPIL: Iris is a dark coloured muscular diaphragm which has a smaller circular opening in its middle. The central circular aperture of iris is called pupil. The pupil appears black because no light is reflected from it. The iris regulates the amount of light entering the eye by adjusting the size of the pupil.

 https://www.youtube.com/watch?v=c4LM-aTIUWM

 Do you know: Eye colors depend on the amount of pigment (melanin) found in the iris.

3. EYES LENS: The eye lens is a convex lens made of a transparent jelly-like material. The eye lens is held in position by cililary muscles. Ciliary muscles help in changing the focal length of the eye lens.

4. Retina: The inside surface of the rear part of the eye ball is called retina. The eye lens focuses the image of the object on the retina. The surface of retina consists of the about 125 million light sensitive receptors called as photo-receptors. When light falls on these receptors they send electrical signals to the brain through optic nerve.


5. RODS and CONES: There are two kinds of light sensitive cells on the retina.
(i) Cone shaped: These cells are sensitive to colour.
(ii) Rod shaped- These cells are sensitive to brightness or darkness or dim light.

6. Blind spot: There are no rods and cones at the point where optic nerve leave the eye ball to go the brain. Sp, if an image is formed is this part of the retina then no signal is sent to the brain. As a result the object is not seen. This part of retina is therefore called the blind spot.

Click on the link for more info about blind spot:

Click on the link for complete information about eyes:

Click on the link for information about working of eye:

Home Assignment

 1. Read page no 258 of your text book.
2. Practice the diagram of an eye.

Comments

  1. ARSH NATH April 27, 2020 at 7:22 PM

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  2. ManvendraMay 6, 2020 at 7:08 AM

    Good morning sir, Manvendra here.

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  3. Pall anandMay 6, 2020 at 7:26 AM

    Good morning sir, I am Pall Anand
    8E
    Roll No.6

    ReplyDelete
  4. Alan RoyMay 6, 2020 at 7:27 AM

    Good morning sir I am Alan Roy roll no 28

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  5. Samrath SinghMay 6, 2020 at 7:28 AM

    Good Morning Sir,
    I'm Samrath Singh

    ReplyDelete
  6. AVI SURANAMay 6, 2020 at 7:31 AM

    Good morning sir I am Avi Surana

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  7. Cyril MartinMay 6, 2020 at 7:32 AM

    GM Sir
    Cyril Martin Roll No. 20

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  8. Maulik JainMay 6, 2020 at 7:35 AM

    Good Morning Sir,
    I Am Maulik Jain

    ReplyDelete
  9. Dakshesh PilaniaMay 6, 2020 at 7:35 AM

    good morning sir
    I am Dakshesh

    ReplyDelete
  10. Aditya SagarMay 6, 2020 at 7:36 AM

    Good morning sir I am Aditya sagar roll no 30

    ReplyDelete
  11. AnonymousMay 6, 2020 at 7:38 AM

    Good morning Sir I am chirag of class 8E

    ReplyDelete
  12. Aditya SinghMay 6, 2020 at 7:38 AM

    good morning sir aditya singh here

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  13. Amit DanielMay 6, 2020 at 7:39 AM

    good morning sir I'm Amit.

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  14. Shaun steniMay 6, 2020 at 7:40 AM

    Good morning My name is Shaun Steni 8 E roll no 44

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  15. Anirudh TrivediMay 6, 2020 at 7:40 AM

    Good morning ms'am,
    I am Anirudh Trivedi

    ReplyDelete
  16. N.RakaloMay 6, 2020 at 7:43 AM

    Good morning sir.
    I am N.Rakalo

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  17. Aditya LalMay 6, 2020 at 7:45 AM

    Good morning sir.
    I am Nishant Lal

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  18. ChristoMay 6, 2020 at 7:45 AM

    Good morning sir I am Christo Sakariyas

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  19. Chetan chandelMay 6, 2020 at 7:45 AM

    Good morning ma'am I am Lakshay Chandel
    Roll no. 7

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  20. Evaan DayalMay 6, 2020 at 7:54 AM

    Good morning ma'am I am Evaan Dayal of 8E

    ReplyDelete
  21. Seerat pal singhMay 6, 2020 at 8:06 AM

    Good morning ma'am I am seerat pal singh 8E roll no 41

    ReplyDelete
  22. Shreyansh AgarwalMay 6, 2020 at 8:17 AM

    Good morning sir
    I am Shreyansh Agarwal
    8E
    Roll No.3

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  23. Aditya AggarwalMay 6, 2020 at 8:25 AM

    Good Morning sir
    I am Tanish Aggarwal
    8-E

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  24. ARSH NATH May 6, 2020 at 8:28 AM

    Good morning ma'am
    I am ARSH NATH
    Roll no 23
    Class 8E

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  25. Rudra sethiMay 6, 2020 at 8:30 AM

    good morning ma'am I rudra sethi

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  26. Cyril MartinMay 6, 2020 at 8:58 AM

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  27. Cyril MartinMay 6, 2020 at 8:58 AM

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  28. RemMay 6, 2020 at 9:22 AM

    Good morning sir .
    Remthanglien Aomar Varte here.

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  29. AnonymousMay 6, 2020 at 9:26 AM

    Good morning sir Arnav Daga here

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  30. Ayush jainMay 6, 2020 at 9:33 AM

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  31. AllenMay 6, 2020 at 10:05 AM

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  32. Falit Mittal.May 6, 2020 at 10:25 AM

    Good morning sir. I am Falit Mittal.

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  33. Keshav vermaMay 6, 2020 at 10:38 AM

    Good Morning sir
    I am Keshav Verma roll no 50

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  34. Justin RussellMay 6, 2020 at 10:42 AM

    Good Morning Sir I am Justin Russell

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  35. Aryan PuriMay 9, 2020 at 8:14 AM

    Good Morning Sir,
    This is Aryan Puri
    Sir there was an error coming before

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