im doing an a level physics presentation on aluminium and im trying to compare aluminium and copper in electricity pylons.i know that copper will have a better conductance than aluminium becasue it has a lower resitivity but i need to come up with a calculation to prove why aluminium is better for use in electricity pylons? i know its down to aluminium being more lightweight than copper and also much cheaper. But im not sure how to create an calculation to show this?:) any help is greatly appreciated
Copper has lower resistance per unit volume, ie, a 1 cm diameter copper wire has less resistance than a 1 cm aluminum wire. BUT, aluminum is much lighter than Cu for the same diameter. If you used an aluminum wire that weighs the same as the 1 cm diameter copper wire, it would have LOWER resistance. And that is why aluminum is used in power transmission, and also in aircraft, where weight is important. to do this you calculate density resistivity which is (resistivity x density). Here is a partial table: Al 28.2e-9 Ω-m * 2700 kg/m? = 76e-6 Ω-kg/m? Cu 17.2e-9 Ω-m * 8960 kg/m? = 154e-6 Ω-kg/m? Ag 15.9e-9 Ω-m * 10500 kg/m? = 167e-6 Ω-kg/m? Au 22.14e-9 Ω-m * 19300 kg/m? = 427e-6 Ω-kg/m? Zn 68e-9 Ω-m * 7130 kg/m? = 485-6 Ω-kg/m? Fe 100e-9 Ω-m * 7870 kg/m? = 787e-6 Ω-kg/m? Note that Al is half that of Cu.
