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When an orbiting electron hits an edge, it goes forward or backward a little, not staying in line.

mjcox2000 wrote:

When an orbiting electron hits an edge, it goes forward or backward a little, not staying in line.

Ah, I see. As laptop97 suggested, you can always make the orbit smaller, or you can go with other methods. Would it be okay with you if trigonometry is used? Also, is this by chance a school assignment? You don't have to answer; I'm just curious.

Anyway, hello mjcox2000 and welcome to Scratch! I wish you a smooth road to learning how to program!

With regards,

ErnieParke

mjcox2000 wrote:

The problem with making the orbit smaller is that I have to then change it for 36 other electrons.

Yes, this is a school project.

Well then, I'm guessing this atom has 5 shells of electrons? I can't tell for sure because I've only been taught about the first three, though 5 should be around the ball-park.

Anyway, one last question. Are you comfortable working with parametric equations, or do you have no clue what they are?

With regards,

ErnieParke

Oops-- correction: it does have 5 shells. I'll have to take down the link and fix it.

mjcox2000 wrote:

Here: http://goo.gl/qgX5a

I added another shell, and am still facing the same problem.

Well, that's because sprites can't go offscreen, and so when you tell an electron to do that, it just goes to the bottom edge of the screen; not as far as you want.

Anyway, seeing as it's the easiest method, I'll go ahead with parametrics.

Here's a script that you could use:

when gf clicked
set [x position* v] to (3.1415)//Position
set [y position* v] to (0)
set [radius v] to ([sqrt v] of (((x position*) * (x position*)) + ((y position*) * (y position*))))
if <(x position*) > (0)>
 set [T v] to ([asin v] of ((y position*) / (radius)))
else
 set [T v] to ((180) - ([asin v] of ((y position*) / (radius))))
end
forever
 set y to (([sin v] of (T)) * (radius))
 set x to (([cos v] of (T)) * (radius))
 change [T v] by (0.1)//Rotation Speed

This nice, though somewhat math-complicated script keeps track of an object's position and will make sure that it's always centered around the origin. Just enter the sprite's position and you should be good to go.

That actually brings up a good point. If you want to, you can get rid of the two position variables, though then you'll have to substitute their values into the equations of the script. And, if you go far enough, you can even remove the variable "radius", though then you'd have to substitute it's value into where it used to be.

Well, I hope that this helps!

With regards,

ErnieParke

Last edited by ErnieParke (2013-04-25 18:49:02)

mjcox2000 wrote:

Thanks! 1 thing-- is there a way to copy and paste in scratch, so I don't need to write that 37 times?

Yes, there is. Just right click what you want to copy, and click duplicate. So, if you wanted to duplicate a script, all you'd have to do is right click the hat block and hit duplicate.

Oh, and by the way, you're welcome.

With regards,

ErnieParke

Last edited by ErnieParke (2013-04-25 21:04:32)

Edit: it is at http://goo.gl/hdhpO