Communication:model the process of accomodation?? (1 Viewer)

[crazylilmonkee]

Hey can anyone help me with this syllabus point?
*plan, choose equipment or resources and perform a first-hand investigation to model the process of accomodation by passing rays of light through convex lenses of different focal lengths
i don't know wat to do!

 

[Halo]

Pass rays of light through different thicknesses of convex lenses (actually, it is the slope of the lens at which the incident light enters and exits that matters - but when you have a 'fatter' lens, generally the slope is indeed more steep). You will find different sizes of lens would produce different focal lengths - ie. the distance between the middle of the lens and the focal point of the rays of light. Also, you will find that thicker lens gives smaller focal lengths.

This is infact the model for accomodation. The lens in your eyes changes shape (thicker or thinner) to produce different slopes so that light will converge (at different focal lengths) onto the retina, producing clearer image.

So when one looks at something close, since the rays of light enters the eye at great angles, the eye accomodates for this by loosening ciliary muscles so that the lens becomes bulkier. This refracts the incident light into smaller focal lengths so that it would focus onto the retina. This is opposed to when one looks at something far away, in which light enters essentially parallel.

 

[crazylilmonkee]

oh ok cool thanks.. now all i have to do is put it into an expt!

 

[s2ophie]

check to see if your school has an optical bench and if so use that!