
Show HN: Simulation-based high school physics course notes - lilgreenland
https://landgreen.github.io/physics/index.html
======
theLotusGambit
I feel like this page really nails down the key feature that makes great STEM
notes: lots and lots of examples. And they're fully worked out too, showing
all steps from formula to result.

So much technical documentation and tutorials and what-have-you seems to want
to stay on an entirely conceptual level, when just throwing in a single
example can make things so much easier to digest.

~~~
lilgreenland
Thanks, In the physics class I teach we go through the examples from the
notes. Then, we follow up with real world labs and engineering projects to
make it even more concrete. I might make my next project documenting the demos
and labs that go with each unit.

~~~
pdm55
Well done.

Two small things I have loved when I came across them:

5 Min Physics from UQ (PHYS1171)
[https://teaching.smp.uq.edu.au/fiveminutephysics/index.html#...](https://teaching.smp.uq.edu.au/fiveminutephysics/index.html#course=phys1171&lecture=L34_QuantifyingRadioactivity)

Newton's cannon. Look at its beautifully simple source code - one short html +
javascript file (I see your javascript code for orbital motion is similarly
easy to follow.)
[https://physics.weber.edu/schroeder/html5/NewtonsCannon4.htm...](https://physics.weber.edu/schroeder/html5/NewtonsCannon4.html)

Something I was going to further explore, if I had had to do more physics
tutoring/teaching:
[https://www.geogebra.org/m/M4nBYbbG#material/fHHvnhjm](https://www.geogebra.org/m/M4nBYbbG#material/fHHvnhjm)

~~~
pdm55
Note that there are other "5 min Physics" explanations and demos from UQ:
[https://teaching.smp.uq.edu.au/fiveminutephysics/index.html](https://teaching.smp.uq.edu.au/fiveminutephysics/index.html)

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lilgreenland
I posted this 2 years ago.
[https://news.ycombinator.com/item?id=17178031](https://news.ycombinator.com/item?id=17178031)

The advice I got from Hacker News was really useful last time. With the switch
to online learning I'm hoping to help out more fellow physics teachers.

Let me know if you have any suggestions.

~~~
ivan_ah
The depth and breadth of topics and examples is amazing. Well done!

My only nitpick would be the formatting of some of the equations. Instead of

    
    
        $$ E = hf $$
        $$ E = (6.626 \times 10^{-34})(10^{9}) $$
        $$ E = 6.626 \times 10^{-25} \, \mathrm{J}$$
    

I think it would be clearer to use

    
    
        $$\begin{aligned}
          E &= hf \\
            &= (6.626 \times 10^{-34})(10^{9}) \\
            &= 6.626 \times 10^{-25} \, \mathrm{J}
        \end{aligned}$$
    

which is the KaTeX-recommended approach for emulating \begin{align _} ...
\end{align_ }.

I would also throw in a word or two of explanations in there, so it's not just
equations, e.g., explain "Using the formula for the energy of a photon, we
find: <eqns>". I guess it would end up being more work for you, but would be
worth it for the benefit of students learning that it's not just about the
numbers, but knowing what you're doing (like you do in the strategy sections).

On the other hand the current format of line-by-line-show-only-the-equation-
steps is very practical too --- from my experience certain students prefer to
see just the practical steps they have to do on the exam, rather than the blah
blha blah around them, even if it can be educational.

It would be interesting to see some of the questions/examples converted into
self-test quizzes. Show a few examples, then ask readers to solve some
problems on their own. I know the idea is they will try to solve on their own
an only reveal the solution after they've tried, but realistically speaking
more likely they will click that arrow ;) So maybe just a delay to force them
to try?

This is getting into the realm of the fancy, but you could maybe make the
reading with a "customizable difficulty level." Beginner = info (maybe hides
certain more advanced topics), all questions solved as examples. Intermediate
= some questions solved as examples, but missing final steps so reader has to
complete them to get the final answer. Advanced = most examples show as quiz
questions reader has to solve on their own...

~~~
lilgreenland
thanks for the ideas

Originally, I tried aligning the equations to the equal signs, but it
increased the display width by about 30%. So, I had to choose from aligning
the equal signs or a 30% font size. It still annoys me to see it centered, but
half my traffic is from mobile.

More explanations is a good idea.

I think putting quizzes for students would work well for multiple choice
questions. Numerical entry might be a bit more work. I'd have to get a library
that evaluates strings into floats.

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lilgreenland
Scroll down to the bottom of the front page to see the Highlighted
Explorables. My favorite is the standing waves simulation.

I'd love someone to critique my explanation of quantum mechanics at the start
of the quantum section. I worked hard on it, but QM is hard, and I may have
got some details wrong.

~~~
rsfern
Lots of nice content here.

I started with the QM section, and it felt like you jumped right in to the
particle theory of light. I realized later that of course you have an in depth
discussion of the wave theory of light, but I think a bit more explicit
connection to that discussion could be helpful.

I particularly like coming back to Young’s double slit experiment, which I saw
in your discussion of diffraction. To me, the most surprising illustration of
the wave/particle duality of light is that single photons passing sequentially
through the double slit still form a diffraction pattern. So these particles
sort of ‘self-interfere’.

One other thought regarding the standing wave demo — maybe you are already
familiar with this, but setting up higher order harmonics is a pretty common
technique among guitar players (and other stringer instruments), where you
pluck a string while touching one of the standing wave nodes. If you’re not
familiar with ‘portrait of Tracy’ by Jaco Pistorius, it’s a really cool and
unique example of this technique

[https://m.youtube.com/watch?v=JXOnhzoC-i8](https://m.youtube.com/watch?v=JXOnhzoC-i8)

~~~
lilgreenland
Revisiting the double slit for a single particle makes sense. I don't know why
I forgot to do it. thanks!

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gitgud
I love the train demo for general & special relativity, they intuitively
explain the theories from frames of reference (ground/train).

This helped me instantly understand the 2 theories, great work!

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flowersjeff
Awesome... Looking for College Chemistry... Would greatly appreciate.

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0xb100db1ade
Used this to get a perfect score on SAT Physics. Thank you, Landgreen!

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maxmunzel
Great Work! One thing I noticed was that some Animations (Conductivity and
Relative Rockets) move on iOS while scrolling. Others (Orbits, Spring-Mass
System and Gravity) work fine...

~~~
maxmunzel
Now they work as expected. Maybe it only occurs the first time you load the
page...

