Re: [Fhsst-physics] Optics topic opinions?

[Mark Horner]

Hi Lindsay

Thanks for the kick on this topic. I just had a chat with Sam (Maths 
coordinator) and we have decided, but its open to debate, to include it 
using the small angle approximation.

We must clearly mark the 'derivation' as Grade 12 level. They will cover 
most of the Optics chapter in Grade 10.

So I would introduce the idea conceptually, quote the formula and use it 
in some examples. Following that have a derivation section which won't 
be very long. That way it doesn't break up the flow but is included.

We will have to tidy up introduction of the small angle approximation 
after having a good look at the ideas we cover in Maths but Physics is 
ahead right now.

How does that sound?

Mark


address@hidden wrote:
> Mark (and/or anybody else):
>
> The topic of apparent depth is coming up in working on the optics chapter.
>  We'd like to include a way to derive the apparent depth of an object in
> the chapter, but there seem to be two options, both with something nasty:
>
> (1)  The nice result:  real depth/apparent depth ratio is the index of
> refraction of water (or whatever material).  This is easy to derive, but
> requires a small angle approximation.  I'm worried that the small-angle
> approximation would be confusing to students.
>
> (2)  Derive a more accurate formula.  Not bad, but ends up with a formula
> involving tangents of inverse sines.  Here I'm worried that students would
> get scared away by that much trig, and also the result isn't terribly
> enlightening.
>
> I guess a third option would be to discuss the topic conceptually and not
> develop a formula.  Any thoughts?
>
> Lindsay
>
>
> _______________________________________________
> Fhsst-physics mailing list
> address@hidden
> http://lists.nongnu.org/mailman/listinfo/fhsst-physics


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Mark Horner 

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