Sunday, June 5, 2011

It's play time with conductive playdough

Recipe for conductive and insulating playdoughs. Their recipe is almost the same as the bbc's. For those who want to measure by weight like I do here's the newscientist's formula.

My main concern with the kid-safe conductive dough is that the high salt content will corrode wires, metals, and--Electra forbid--test instrument (multimeter) probes. According to Anne Marie Thomas a 1cm long dough with a diameter of 1cm has a resistance of 80ohms. Given the equation

R = ρ l/A

R = resistance in ohms
ρ = resistivity of the material
l = length of material
A = area

we can solve for ρ of this conductive playdough:

80ohms = ρ (0.01m) / [(0.01/2)^2(3.14)]

ρ = 0.63

I'm not the creative type so right now I can't think of any serious use for this stuff. The material isn't stable and will dry out and probably crumble, and its mechanical and electrical properties will change in a matter of weeks so the lifespan of circuits employing it will be quite limited.

No comments:

Post a Comment