Frustrations making useful / not fun lessons, any opinions?

Forums for educators and researchers to discuss educational aspects of Algodoo.

Frustrations making useful / not fun lessons, any opinions?

Postby ReinhardtScience » Thu Jun 06, 2013 2:48 pm

So I will be using Algodoo at a school with 1 to 1 device program. Every student will have it, and every student will be required to produce lab reports with graphing functions at .csv exports.

To get ready I am starting to make things that are missing from Algodoo. Like a comprehensive way to deal with Gravity, + Charges, - Charges, Van de waal forces, etc using a well thought out system of layers.

Maybe this has been done before, but I wouldn't know it since the top page stuff is creative, but is more on the 'mildly' entertaining than on simulating more advanced topics.

Is there a better place for that? Thoughts appreciated. I'm 'MrReinhardt' in Algobox if you have any comments.
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Re: Frustrations making useful / not fun lessons, any opinions?

Postby DrAgon » Thu Jul 18, 2013 12:33 pm

Hello ReinhardScience,
you are not the first one who tries to extend the abilities of Algodoo

Charges:
it really works, to implement charges, though only upto 20 of them are
useable on an average computer without slowing the simulation down
too much. This can be done using the scrip-language Thyme, using a
usually unused variable-content of objects, where the charge of the
object is stored can carried around the simulation.
You then have to create the electrical-force-vector for each object q
that is calculated by F= Sumofall i ( q*qi *vector(r-ri)/distance³) and create your
additional velocity-changing dv=a*dt=F/m*dt, which you add then to
the velocity of the object. ( r and ri are the vector-positions of the
two interacting objects ).
Difficult is to get these calculations really fast, so i tried somelthing
in
http://www.algodoo.com/forum/viewtopic.php?f=13&t=9663
but the result of this research was, that the builtin-functions are
faster then the self-built-even-with-with-tricks-functions, e.g. i thought
i could do very fast square-root-approximations, that are necessary to
calculate the distance of the objects. Also, the amount of calculations
raises quadratically with the number nof charges , that is n*(n+1)/2.
If you want, i can add a little scenario on the algobox, when i am
out of holidays in some weeks, that is working with this.

Van der Walls forces
Which kind of force you like to simulate / implement?
Dipol-moment is simple to simulate, once you get the + and - charges, you simply
attach 2 charges stiffly to a dipol. This way you can simulate waterdipol
falling down next to a charge, and show that the water is attracted
to the charge.

Layer-system
Indeed, i am working also on a layer-system to get around the self-made-velocity-changing
and some attempts work with high number (100) of charges allready. For this, i created
objects, that use Thyme-script, so that if one clicks on them, they create the appropriate
charge out of several needed components. I didnt finish this yet, need some tests still,
e.g. i am testing if the repulsion of + + and - - has same force as the attraction
as + - and - +. Also i am thinking on damping, that is unphysical, but enhances the
squiggeling fast-moving charges. Am working on wires, and the first real good result will be an
influence-machine, but will be ready in about 3 months.

Pädagogical concepts
I am currently working on pädagogical concept for my own country ( Germany )
to get algodoo as a main tool for learning science. Maybe you can look at my forum
entries too, so we can work together in some lines?
best regards, DrAgon


so..... i am working right now on displaying the force-arrows, by creating an
object and add a vertical object with the length of volume*density*gravity,
which has only last collision group. When i am finished with this, i ll continue
to post my progress in that. ( date: 20.07.2013).

The free version 2.1.0 contains the chance to display force-vectors
gravity, normal-vector on the plane and friction,
Image
to switch on, you have to klick on the place where the red arrow
above directs you.
But: it is not possible
( i dont see any way ) to display just the forces on the objects that
i want ( skip the others ), so i work further on the other way of displaying it.
24.7.2013
Now i have finished the scenario:
http://www.algodoo.com/algobox/details.php?id=71337
It works well, for my taste there dont have to be "Arrows" to
display the forces, as every force has a counterforce anyway.
One big improvement in addition to the picture above is,
that the normal vector N above is bigger then the gravityforce
vector, and it should be the other way around.
25.7.2013
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