Electricity and Magnetism
After the study of Gravity this is the first fundamental force we can study in detail. The Electric force is arguably the single most important force in terms of its immediate relevance to your life. It is the reason you don't fall through the floor as you walk along it. It is the foundation for all chemical reactions. And it is the means by which you see. This is the basis for all the electronic devices you enjoy on a daily basis.
| Electrostatics | |
| This is the beginning. Use this applet*
to move a test charge about to see how the force on it can be described
by an arrow pointing in the direction of the force. As you move the
test charge around note how the direction and the magnitude of the
arrow changes. As you place electrons around the charges ask yourself
"How might I describe the force without knowing the magnitude of the
'test charge'?"
*Note that this applet contains a mistake. The test charges have a (-) charge. They are supposed to be (+). |
This is one of the coolest applets for visuallizing Electric Fields
that I know. There is alot of information in this applet. It can
describe geometries beyond anything we covered in class so start small
and then build to more complicated stuff later. Star with the second
menu set to Display: Field Vectors
When you have a sense of the field and you are ready to move on consider the next box. |
| When an object is moved with or against a force, work is done. Since we are now dealing with an electric field and not a force field we can define a different quantity: a set of Potential Contours. Try setting the display to Equipotentials and drag the cross section around to get a sense of what this looks like. Notice anything about the relation between the equipotential contours and the E field? | |
| Electricity | |
| This is the practical
application of all this electric force physics. Check out these applets
for experimenting with different types of circuits.
You can play with some circuit elements to get the idea of how to hook components together. |
Start with Ohm's Law. This is the most basic of relationships between Voltage and Current. This simple applet gives you a basic introduction to the operations of circuits. |
| Next try some tricks with Kirchhoff's Laws by putting some resistors in parallel and series and watch what happens to the current and voltage relationship. | |
| Here is a very sophisticated circuit simulator. You can model DC and AC circuits and see how active components respond to varying voltages. You can chart varying voltages as look at a simulated oscilloscope. | |
Momentum
Magnetism