Because I think what students will get are just two numbers. Is it really better that way?

I hope we can discuss: Is it better to show those two angles? Especially, you want it to be shown in degree.

The real physics meaning of refraction law is the ratio of those two distances is a constant.

That is why I draw those two lines and show their distance. And I hope students to find out the relations (for reflection and refraction cases).

And I think this is more important than just showing two numbers.

It is more difficult for student to find relation between those two numbers , especially if there were shown in degree.

Even there were shown in radian, the relation between those two number is n[sub]1[/sub]*sin(c[sub]1[/sub]) =n[sub]2[/sub]*sin(c[sub]2[/sub]).

Can student find more physics meaning with those numbers shown in applet?

I think we should keep the current version:

The ratio of those two distances (horizontal displacement) is a constant. And this is the physics of the refraction law.

n[sub]1[/sub]*sin(c[sub]1[/sub]) =n[sub]2[/sub]*sin(c[sub]2[/sub]) is a mathematics relation.

L[sub]1[/sub] and L[sub]2[/sub] are the distances shown in the applet.

sin(c[sub]1[/sub])=L[sub]1[/sub]/R, and sin(c[sub]2[/sub])=L[sub]2[/sub]/R

So n[sub]1[/sub]*L[sub]1[/sub]=n[sub]2[/sub]*L[sub]2[/sub] is the result of refraction law.

Or L[sub]1[/sub]/L[sub]2[/sub]=n[sub]2[/sub]/n[sub]1[/sub] which is a constant.

This is the reason why the applet was designed this way, and why I draw a circle to help students to find relation between those two distances when light is refracted (Law of refraction) --- It is also the meaning of sin(c).