[Fhsst-physics] Optics comments (for now)

[Mark Horner]

Hi Lindsay

Sorry about the delay, using the hackathon to catch up with things. 
Comments on the version of optics you sent me,
I just flew through and here is a rough list of what came to mind. 
Filter as you see fit. If you said need table or
figure then I didn't bother repeating that.

In the second paragraph you have a \nts about more EM wave stuff. Don't 
get into this too much because its
the major part of teh modern physics chapter and they will only do that 
in Grade 12. I think its ok just to
state it like you do, or more forcefully as it will be mentioned at the 
end of the waves chapter which will
come before geometrical optics.

The first sentence after "Properties of Light" we should cut. 
Birefringent materials material are a classic
example of violation of this. Just cutting the sentence doesn't affect 
the rest of the paragraph.

Here is a list of refractive indices which can be used for the table. 
Choose the ones you like most. You can
say in a footnote or table caption that this is for light with a 
wavelenght of 589.3 nm and mention that sometimes
the speed depends on the wavelenght but they aren't going to learn about 
that now.

Material        n
Vacuum  1 (exactly)
Helium  1.000036
Air at STP      1.0002926
carbon dioxide  1.00045
water ice       1.31
liquid water (20°C)     1.333
ethanol         1.36
glycerine       1.4729
rock salt       1.516
polycarbonate   1.59
bromine         1.661
glass (typical)         1.5 to 1.9
cubic zirconia  2.15 to 2.18
diamond         2.419
moissanite (silicon carbide)    2.65 to 2.69
cinnabar (mercury sulfide)      3.02
gallium phosphide       3.5
gallium arsenide        3.927
silicon         4.01

The answer to worked example 1 is outside the worked example environment.

Under the Law of Reflection we still need some sort of description of 
the plane of incidence. I'll look
around at digging up a figure but its the first time we say "plane of 
incidence" and we should just be
clear so that nobody gets confused by it.

Ah - we spell aluminium a little differently ;)

I really like the pstricks images and I'm very impressed that you pushed 
through on  how to make them - I never really got into it.

Here is a trick to make the figure not shift around so they are in the 
correct sections. We can't expect high school students to actually look 
for teh figure. Define the figure environemtn with
\begin{figure}[H]

The H means "it must be here" - normally  you can do things like htb! 
which means please try to put it here or at teh top or at the bottom of 
a page and the explamation means try hard. But the capital H just means 
put it here regardless of how much it screws other thigns up :)

In the first paragraph of Refraction add a reference to the refraction 
of waves. Just something like "We know that light is an electromagnetic 
wave and that waves are refracted when they change medium."

Once again I think the figures are looking good and they are used well 
to explain things we must just ensure the figure is as close to the 
explanation as possible. If you don't put the pspicture inside a figure 
environment it will also be put exactly where you have it in the text 
but it won't have a caption or be numbered or referencable.

The worked examples in Snell's Law have a minor issue with \westep - it 
expects you to give it a string \westep{description} which
should describe the step. These descriptions are to try to empahsise a 
global problem solving strategy. Things like the first
step being a unit conversion.

For total internal reflection you can use anything from Wikibooks, even 
diagram inspiration:
http://en.wikibooks.org/wiki/Total_internal_reflection

We can also steal the pros and cons of fibre from:

http://en.wikibooks.org/wiki/Fibre_optics

Then it gets into the diagram dense part where all the lens stuff comes 
in. If you use the [H] on figures they'll be able to break
up the text and I think everything will look fine.

For the most part we need more diagrams but the text is looking good and 
so is the referencing diagrams and the explanations.
How is your time looking? Are you getting quick to make diagrams yet?

Thats it for now.
  
Good job.

Mark

--
--
Mark Horner                                                                                                         
Jabber/AIM/Yahoo/Skype/Google:   marknewlyn                                                               

Co-author:
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