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.