Re: [Phys-L] video games versus quantum physics

[John Denker <jsd@av8n.com>]

On 10/25/2013 05:35 AM, Anthony Lapinski wrote:
> A colleague sent this to me. Thought I'd share it with the group.
>
> http://www.thetakeaway.org/story/when-quantum-physics-meets-video-game/#.UmpkL1zLhrk.mailto

The following demo is more informative:
  http://qcraft.org/

At 2:54 the narration says
  "qcraft isn't meant to be a perfect simulation of quantum physics"

Ay, that's the understatement of the year.  The whole thing
is the poster child for wrong physics and bad pedagogy.

There is a principle of pedagogy that says one should /first/ 
introduce the idea and /then/ give it a name.  That stands 
in contrast to introducing a lot of empty buzzwords and then 
(maybe) attaching meaning to them later.

In contrast, qcraft introduces various quantum-mechanical
buzzwords (observer-dependence, superposition, entanglement)
and then connects them to utterly wrong concepts.  The most
a student could hope to gain is some exposure to the buzzwords,
but if they are connected to wrong concepts, what's the point?

I hate to belabor the obvious, but the idea that "observing"
the light coming from a torch could change the state of the
torch (not to mention other torches) is just ridiculous.
The idea that "observing" a chunk of gold from a funny angle
could turn it into a chunk of diamond is just ridiculous.
For one thing, that's not what QM means by "observation",
and just as importantly, the conservation laws are upheld
by all parts of QM, including quantum measurements.

Furthermore:  Suppose you wanted to get across the idea
that QM explains why atoms have some nonzero size, despite
the strong attraction between the proton and the electron.
There is nothing in qcraft that gives you any traction on
this idea ... or any other useful quantum-mechanical idea.

Constructive suggestion:  If you want to teach second-graders
something that will advance their understanding of quantum
physics, bring in a big round bowl of water and experiment
with setting up various wave patterns.  It is not hard 
to set up good models of 1s, 2s, 3s, px, py, p-, and p+
stationary states.  The students do *not* nead to learn 
the names;  it is enough to know that various wave patterns
exist in the bowl, and that analogous wave patterns exist
in atoms.

There's a lot more you can do along these lines; see e.g.
  http://www.av8n.com/physics/wavefunctions.htm      [1]

When using simulations and computer models, or any other
kind of models, the models are vitually never self-explanatory.
All models are imperfect approximations, so it is important 
to explain clearly which /parts/ of the model are faithful 
to which /parts/ of the real physics.  This is why the
teacher gets the big bucks, to combine each model with
other models and with suitable explanations.

Merely saying "qcraft isn't meant to be a perfect simulation 
of quantum physics" doesn't come anywhere near meeting the
pedagogical responsibility.  It would be better to explain
the *specific* ways the model is unfaithful to the physics, 
and -- more importantly -- to identify some way(s), if any,
in which the model is actually faithful.

In the case of qcraft, AFAICT there aren't any faithful
bits, or if there are, they are so thoroughly entangled
with nonsense as to be unrecognizable.