simplified model of the eye in which the front of the eye is a single len

[lookang]

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

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


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!!

[Fu-Kwun Hwang]

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.

[lookang]

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

my this friend also is talent in Flash.

[Fu-Kwun Hwang]

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
<applet code='users.ntnu.fkh.eye_pkg.eyeApplet.class' archive='http://www.phy.ntnu.edu.tw/ntnujava/ejsuser/2/ejs_eye.jar' name='eye9396' id='eye9396' width='806' height='473' mayscript=true><param name='draggable' value='true'></applet>
Embed a running copy link(show simulation in a popuped window)
<a href='http://www.phy.ntnu.edu.tw/ntnujava/msg.php?smfejs=9396' target='smfejs'>Run simulation</a>

Full screen applet or Problem viewing java?Add http://www.phy.ntnu.edu.tw/ to exception site list
Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop. This work is licensed under a Creative Commons Attribution 2.5 Taiwan License

• 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!

[lookang]

nice!
thanks

[ooypoodhuajung]

hello

[sajidtoor]

thanks for sharing...!