# Examples of refraction

#### yakabod

examples of refraction being abrupt and another that is gradual.

been thinking and nothing have popped in my mind?

easy examples are ok as long as i get it :)

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#### Tom Mattson

Staff Emeritus
Gold Member
Hi Yakabod,

I've noticed that both of the threads you posted here contain questions not on problems or concepts, but on research questions (in other words, the question is looking for straightforward factual answers, not reasoning or problem solving). That poses a bit of a problem here, because we have a policy: We don't do your homework for you. But, to answer your question is to give you the whole thing.

Here's the first one:

What have you studied that is an example of abrupt refraction? In other words, what kind of setup involves an instantaneous change of direction of a beam of light?

#### yakabod

so is one example when u put a pencil in a glass of water and it bends???? is that one?

#### Tom Mattson

Staff Emeritus
Gold Member
Yes, that would be a good example. Now, here's the next question:

Why is the refraction abrupt?

#### yakabod

ok so im thinking that exmaple i said was an example of gradual? but is this s good example for abrupt..

when also light passes a concave mirror or glass and it bends in a diffrent direction? [?]

#### Tom Mattson

Staff Emeritus
Gold Member
Originally posted by yakabod
ok so im thinking that exmaple i said was an example of gradual? but is this s good example for abrupt..
It most definitely is not gradual.

You see the pencil in air pointing in one direction, and then suddenly you see the pencil pointing in another direction. This is because the light refracted abruptly.

Now, my question is, Why is it abrupt?

To answer that, you have to think about the cause of refraction: Passing from a medium with one index of refraction (in this case, air) to a medium with a different index of refraction (in this case, water).

when also light passes a concave mirror or glass and it bends in a diffrent direction? [?]
Whoa! You're talking about reflection here. That is not the same as refraction.

#### yakabod

thanks alot of making my mind straight now..

...and how i got refraction and relection confused

hehe thanks..

#### Tom Mattson

Staff Emeritus
Gold Member
OK, so now back to The Inquistion. Muhahahaha!

Why is the refraction abrupt when the light passes from the air to the water? (This is an easy one, so don't think too hard )

#### yakabod

tell you the truth i really have no idea...

thats why im in summer school...

but let me think about it..

#### yakabod

are the waves bending because the vary of temperature?

cool vs warm air the waves travel upwards

warm vs cold air the waves travel downwards

is that it?

#### Tom Mattson

Staff Emeritus
Gold Member
No, that's not it.

Like I said before, think about what causes refraction. It is caused by passing from one medium to another.

So...

The refraction is abrupt because the change of medium is abrupt.

Now, what do you think makes for gradual refraction.

#### cmccarra

Because the pencil is moving from a dense medium to a less dense medium. Correct?

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