Graphite Pencil Resistors

This is a fun, simple, kid friendly project requiring very few materials which demonstrates the concept of electrical resistance. It does this by having the participant cut graphite pencils to varying lengths to measure the resistance of the graphite inside them(Carbon is one of the most common resistor materials used in circuits!), which will demonstrate how the amount of resistive material correlates to its resistance.

You will need:

• Graphite Pencil(s)
• Saw(or some other cutting instrument)
• Ohmmeter
• (Tape and a sharpie is helpful but not necessary)

If done right, the resistance should decrease with the length.

Have a target resistance and try to cut your pencil to a length that gives it that resistance; (you can try doing these things with the graphite removed from the wood if you prefer); use a multimeter and a battery in a circuit with your resistors to measure how the current changes with the resistance; record measurements; look for patterns; show a friend to spread the knowledge and garner interest in science among others!