To understand electric
fields and electromagnetic waves,
you need to know how charges (such as "negative"
electrons and "positive"
protons ) cause each
other to move.
Yeah, but it just got sucked into the positive charge and got swallowed.
Click the mouse
anywhere in the box. You created an electron! It's a particle with negative
charge and very small mass.
That's because the positive charge exerts an invisible, attractive force
on the electron -- an electric force. Try putting the electron
in different places. How long can you keep it alive?
If I put one near the edge of the box, it gets sucked in a lot slower.
Yes -- the electric force is like an invisible spring, but as the charges move farther apart, a weaker spring pulls them together.
Now see what happens when you give the electron a little "throw" as you set it down. To do
this, click-drag the mouse in any direction. The line shows the direction of the throw and
its length shows the speed.
Hey, if I start it off just right, the electron keeps looping around the
proton and never crashes into it.
You've just created an early model of an atom!
Does this mean that the electric force is some how different when the electron starts with a velocity?
No, the force, or pull, depends only on where you put it, not on the velocity.
But an electron's motion depends on both the force on the electron and its
velocity, which are often in different directions. See what happens when
you first click on the button "show force," and then put an electron down
with a velocity in a different direction.