Level 5: Ohm's law

Electricity and magnetism · level 5 of 8 · rough age 12-13 (a guide for parents; anyone can start anywhere)

Resistance is how hard a part makes it for current to flow. Ohm's law, \(V = IR\), ties it to voltage and current. This level uses it to solve series and parallel circuits, finds the resistance of a wire from its length and thickness, and shows that copper wires on a cold Mars night carry current more easily than on Earth.

Lesson	You will be able to
Resistance	Find a resistance from \(R = V/I\)
Ohm's law	Use \(V = IR\) and read a current-voltage graph
Series circuits	Add resistances in series and share out the voltage
Parallel circuits	Combine resistances in parallel and add the currents
Resistance of wires	Use \(R = \rho L/A\)
Cold wires on Mars	Find how resistance changes with temperature

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