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Information about this web site => Request for physics Simulations => Topic started by: lookang on July 26, 2012, 01:28:40 pm



Title: simplified model of the eye in which the front of the eye is a single len
Post by: lookang on July 26, 2012, 01:28:40 pm
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)

Additional Objective besides the usual:
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
(http://www.phy.ntnu.edu.tw/ntnujava/index.php?action=dlattach;topic=2507.0;attach=4874;image)

normal eye with near object, but eye len can adjust to focus
(http://www.phy.ntnu.edu.tw/ntnujava/index.php?action=dlattach;topic=2507.0;attach=4876;image)

normal eye dont near glass, not focus
(http://www.phy.ntnu.edu.tw/ntnujava/index.php?action=dlattach;topic=2507.0;attach=4878;image)

for 2:

near sighted eye not focus
(http://www.phy.ntnu.edu.tw/ntnujava/index.php?action=dlattach;topic=2507.0;attach=4880;image)

near sighted eye  focus with help of a concave len
(http://www.phy.ntnu.edu.tw/ntnujava/index.php?action=dlattach;topic=2507.0;attach=4882;image)

for 3:

far sighted eye not focus
(http://www.phy.ntnu.edu.tw/ntnujava/index.php?action=dlattach;topic=2507.0;attach=4886;image)

far sighted eye  focus with help a convex len with far object
(http://www.phy.ntnu.edu.tw/ntnujava/index.php?action=dlattach;topic=2507.0;attach=4888;image)

far sighted eye  focus with help a convex len with near object
(http://www.phy.ntnu.edu.tw/ntnujava/index.php?action=dlattach;topic=2507.0;attach=4890;image)

thanks!!


Title: Re: simplified model of the eye in which the front of the eye is a single len
Post by: Fu-Kwun Hwang on July 26, 2012, 03:58:40 pm
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.


Title: Re: simplified model of the eye in which the front of the eye is a single len
Post by: lookang on July 26, 2012, 04:12:12 pm
wow!
taiwan got many talent teachers.
thanks for sharing this :)

my this friend also is talent in Flash.


Title: Re: simplified model of the eye in which the front of the eye is a single len
Post by: Fu-Kwun Hwang on July 26, 2012, 10:43:08 pm
It is still in the alpha stage. It is not finish yet. I need to find more time to work on this.


Title: Re: simplified model of the eye in which the front of the eye is a single len
Post by: lookang on July 28, 2012, 07:57:20 pm
nice!
thanks


Title: Re: simplified model of the eye in which the front of the eye is a single len
Post by: ooypoodhuajung on September 18, 2012, 12:27:30 pm
hello


Title: Re: simplified model of the eye in which the front of the eye is a single len
Post by: sajidtoor on December 20, 2012, 11:45:31 am
thanks for sharing...! ;)