Resources for COSMOS
Here are some web sites that do simulations of physical phenomena.
Please find more such websites and let me know!
Projectile simuilation. How far will the cannonball go, as a
function of angle. Interestingly, computing such "ordinance tables"
was one of the most compelling reasons used to motivate governments to
fund the development of computers (e.g. for Babbage's Differential
Engine and the Eniac)
A momentum and friction simulation lets you play pool. Incidentally,
"Ball im Loch" is German for "the ball went in the pocket".
Satellite orbit calculator.
See if you can get the satellite in orbit close to earth.
This was another early use of computers back in the "space age".
Here you have two stars (or whatever) in orbit around each other, and
you get to introduce additional bodies (e.g. asteroids) to see how they are
affected. I suggest hitting "ZAP" to clear the space, then click
a bunch of times somewhere to introduce some asteroids. Now see if you
can manage to get an asteroid that will remain in orbit. (Moving the "+"
in the upper left-hand box affects the initial velocity of the asteroids.)
NASA uses computers to figure out how to use planets like Mars and Venus
to "slingshot" satellites to more distant planets.
This might not be much fun, but it shows an incredibly
important application of computers - simulating the behavior
of the atom that form a molecule. You can drag the atoms
to different locations, then repeatedly click "Energy Minimize"
to see how they move back towards a stable shape. Such programs
are used by computational biologists to, for instance, to try to
determine the structure of proteins, which can help design drugs.
I haven't totally figured this one out, but it seems to show how much
lift an airplane wing of different shapes produces. In any case,
making more fuel-efficient cars and airplanes is an important
application of computers.
Fission reaction. One of the major problems faced by the Manhattan
Project in developing the atomic bomb during WW II was to determe how
much uranium was needed to sustain a nuclear reaction. They didn't
have computers to do simulations like this one, but they had hundreds
of people doing calculations by hand. (Actually, they also had some
incredible mathematicians figuring out how to get the answer without
simulating zillions of particles.) Today, the most powerful supercomputers
are in the ASCI project, whose mission is to determine, by simulation, if our
nuclear weapons will still work, since by international treaty we can't
actually set them off.
This looks like it might be fascinating, but I haven't actually
downloaded the software to try it out. The general idea is you program
how each little agent behaves (like bees or cars), then StarLogo
simulates a whole bunch of them to show what their collective behavior
is. (This is really how every system in the universe works!) Click on
the "Projects" button to get examples of what StarLogo supposedly can do.
This isn't really a very good example of a physics simulator, but it
does raise the amusing mathematical question (which you have learned
enough in school to answer) as to whether there is a limit to how much of an
overhang you can get with a pile of books as high as you want.
display the page. Then
use the "View" menu and click on "Source". This should put you into
NotePad, viewing the code that created the page. There are suggested
exercises at the top of the files.