Agroup 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