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 Author Topic: simplified model of the eye in which the front of the eye is a single len  (Read 17594 times) 0 Members and 1 Guest are viewing this topic. Click to toggle author information(expand message area).
lookang
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 : 1 users think this message is good1 simplified model of the eye in which the front of the eye is a single len « Embed this message on: July 26, 2012, 01:28:40 pm » posted from:SINGAPORE,SINGAPORE,SINGAPORE

Dear Prof Hwang,

My friend in school wishes for an EJS applet that can allow inquiry into the working of a human eye (simple think converging lens) with another thin converging/diverging lens in front of the human eye.
from http://webphysics.davidson.edu/physlet_resources/dav_optics/Examples/eye_demo.html by Melissa Dancy and Wolfgang Christian
The applet is a simplified model of the eye in which the front of the eye is a single converging lens.

i tried to design one from your original applet but the codes is really beyond my ability.

would you be releasing a physics simulation for me and my friend to work on?

this are the objectives

1) To show that human eye lens is of variable focal length. We need to stretch/compress our eye to see far/near object
2) People with short sighted have a upper limit to their focal length
3) People with far sighted have a lower limit to their focal length
4) Old people can have both upper/lower limit to their focal length and hence need bifocal lens

thanks!

this is the original email from my friend

Quote
Hi Bro,

I was trying to show how our eyes work and was using your applet:
http://weelookang.blogspot.sg/2010/06/ejs-open-source-converging-diverging.html

I'm trying to make it a virtual lab to reinforce their learning.

Would it be possible to make the following changes?
1) Full screen capability like Fu-kwun with more space for image/object: Too little room to show image/object (always out of screen; and unable to show object/image at "infinity")
(I saw your auto function but would much prefer a fixed screen for ease of comparison)
2) Default uncheck blue line (with option to check it): In practice, we only draw 2 lines to determine the image. 3rd line is merely for checking answer.
3) Option to add in "eyeball with retina" in background?
4) Disable –ve f (since eye cannot be –ve f and its not in syllabus)

1) To show that human eye lens is of variable focal length. We need to stretch/compress our eye to see far/near object
2) People with short sighted have a upper limit to their focal length
3) People with far sighted have a lower limit to their focal length
4) Old people can have both upper/lower limit to their focal length and hence need bifocal lens

Thanks,
TK

i came up with this story board for ease of understanding the what the applet can do.

for 1:
normal eye focus

normal eye with near object, but eye len can adjust to focus

normal eye dont near glass, not focus

for 2:

near sighted eye not focus

near sighted eye focus with help of a concave len

for 3:

far sighted eye not focus

far sighted eye focus with help a convex len with far object

far sighted eye focus with help a convex len with near object

thanks!!
 normaleye.png (12.29 KB, 608x287 - viewed 1504 times.)  normaleyenearobject.png (13.91 KB, 611x294 - viewed 1450 times.)  normaleyedontneedglass.png (15.01 KB, 608x293 - viewed 1415 times.)  nearsightedeye.png (11.81 KB, 610x292 - viewed 1476 times.)  nearsightedeyeglass.png (13.5 KB, 608x292 - viewed 1480 times.)  nearsightedeyeglass01.png (15.53 KB, 610x291 - viewed 490 times.)  farsightedeye.png (11.91 KB, 608x291 - viewed 1366 times.)  farsightedeyeglassfarobject.png (13.37 KB, 610x289 - viewed 1422 times.)  farsightedeyeglass.png (14.75 KB, 609x290 - viewed 1420 times.) « Last Edit: July 26, 2012, 02:01:15 pm by lookang » Logged
Fu-Kwun Hwang
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 « Embed this message Reply #1 on: July 26, 2012, 03:58:40 pm » posted from:Taipei,T'ai-pei,Taiwan

I will try to find time to do it.
The following is a flash created many years ago by one of teacher in Taiwan.

You can click at the three images at the right. Drag butterfly from left to right.

You can also add lens to see how it might work.
However, it was created with Chinese characters.
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lookang
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 « Embed this message Reply #2 on: July 26, 2012, 04:12:12 pm » posted from:SINGAPORE,SINGAPORE,SINGAPORE

wow!
taiwan got many talent teachers.
thanks for sharing this

my this friend also is talent in Flash.
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Fu-Kwun Hwang
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 « Embed this message Reply #3 on: July 26, 2012, 10:43:08 pm » posted from:,,Satellite Provider

It is still in the alpha stage. It is not finish yet. I need to find more time to work on this.

Embed a running copy of this simulation

Embed a running copy link(show simulation in a popuped window)
Full screen applet or Problem viewing java?Add http://www.phy.ntnu.edu.tw/ to exception site list
• Please feel free to post your ideas about how to use the simulation for better teaching and learning.
• Post questions to be asked to help students to think, to explore.
• Upload worksheets as attached files to share with more users.
Let's work together. We can help more users understand physics conceptually and enjoy the fun of learning physics!
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lookang
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 « Embed this message Reply #4 on: July 28, 2012, 07:57:20 pm » posted from:SINGAPORE,SINGAPORE,SINGAPORE

nice!
thanks
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ooypoodhuajung
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 « Embed this message Reply #5 on: September 18, 2012, 12:27:30 pm » posted from:Bangkok,Krung Thep,Thailand

hello
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sajidtoor
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