Conducting putty is a unique and versatile aid to teaching the topic of resistivity and the dependence of resistance on length and cross‐sectional area of the conductor
The material is supplied in 'blobs' of approximately 100g in mass
A conductive putty cylinder 60mm long and 20mm in diameter has a resistance of about 20Ω
Coins or washers placed on the ends of the cylinder can be used to connect it into a circuit
By altering the length and diameter in simple multiples, the relationship can quickly be established
The substance is harmless, but messy, so plastic gloves are supplied for handling the putty
