Hi all, Biologist posting here. We have a thermal gradient that doesn't seem very stable. Right now, our setup is the following: hot water runs through one aluminum bar and cold water runs through another. the two bars are about 25cm apart. There is a thin aluminum plate resting on the bars. The heat and cold transfer through the aluminum plate such that there is appx a 1 degree (Celsius) / 1 cm gradient. However, we've encountered all kinds of problems with measuring this gradient, keeping the water at the right temps, etc (pretty much anything you can imagine, it's happened). I'm doing some exploratory work to see how much time and money developing a new gradient would cost. Is there a way (an equation to use?) where we can run copper wire at 1 cm intervals down a plate (kind of like the defroster on the rear windshield of cars) and control the temperature of each individual wire to create the same gradient? (so, set the first wire to 30 degrees, the second to 29 degrees, etc?) I guess what I'm looking for is a way to adjust the voltage (?) running through the copper to create more or less heat, but in such a way that we know what temperature the copper is. And, if we can adjust the voltage going into the copper, we can make the gradient more or less steep. As for running the copper down the plate, would this be an open circuit? As in, if somebody touched it, they'd get a shock? Is there a way to sandwich the wire between two sheets of glass so that the heat transfers effectively but nobody burns a finger? I'm sorry this is so awkwardly worded-- it's been a long time since I've done any electrical work, and it's been a long day :-) can anybody help?