resistance
Resources

PhET: Circuit Construction Kit: DC - Virtual Lab
Do you like Circuit Construction Kit: DC, but want to use only in-line ammeters? This is the sim for you! Experiment with an electronics kit. Build circuits with batteries, resistors, ideal and non-Ohmic light bulbs, fuses, and switches. Determine if everyday objects are conductors or insulators, and take measurements with a lifelike ammeter and voltmeter. View the circuit as a schematic diagram, or switch to a lifelike view.

PhET: Circuit Construction Kit: DC
Experiment with an electronics kit! Build circuits with batteries, resistors, ideal and non-Ohmic light bulbs, fuses, and switches. Determine if everyday objects are conductors or insulators, and take measurements with an ammeter and voltmeter. View the circuit as a schematic diagram, or switch to a lifelike view.

PhET: Ohm's Law
See how the equation form of Ohm's law relates to a simple circuit. Adjust the voltage and resistance, and see the current change according to Ohm's law.

PhET: Resistance in a Wire
Observe changes to the equation and wire as you play with the resistivity, length, and area sliders.