A group of students is investigating whether copper is a better thermal conductor than steel. The students take a copper wire and a steel wire of the same length and diameter. They put equal lengths of wax on one end of each wire and dip the other end into a beaker of hot water. The length of wax left on the wires after 10 minutes is shown.


Experimental Observations
Copper Steel
Original length of wax: 3 cm 3 cm
Length of wax after 10 minutes: 0.7 cm 1.8 cm


What was the dependent variable in this experiment?
Type of wire used
Original length of wire
Original length of wax
Thermal conductivity of wire