A bimetallic thermostat strip is straight at 20 C. The brass side has alpha = 19 x 10^-6 /C and the steel side has alpha = 12 x 10^-6 /C. When the room warms to 30 C, (a) which side becomes the outer curve of the bend, and (b) explain in one line how this switches a heater off. Solution: (a) Brass expands more (larger alpha), so the brass side forms the outside of the bend - the strip curves away from the brass side, i.e. toward the steel side. (b) The bending tip moves away from (or onto) an electrical contact, breaking (or making) the heater circuit at the set temperature.