Description
A pencil lead and its drawn line are part of a simple circuit. As the line is drawn longer and longer, the resistance of this circuit is observed to increase, or alternately the current is observed to decrease.
1. Connect (in series) a 6 volt battery, a high graphite art pencil, a thickly drawn line (~3 cm. long), and a multimeter set up to measure resistance.
2. Extend the length of the line while observing the change in the circuit's resistance.
ALTERNATES:
- To demonstrate a conductor's width and resistance inverse proportionality, double the thickness of the line and the resistance will decrease
- Draw (curved) lines side by side to demonstrate how parallel circuits will generally have decreased resistance.
NOTE: The thickness and width of these hand drawn lines is difficult to control. Do not expect multimeter readings that can quantitatively compared.

Equipment
Very soft graphite Pencil
Support Equipment
Ohmmeter