Two groups of students are doing controlled experiments with electromagnets. They each start with an electromagnet that has 30 winds on the core, one D-cell, and a switch. All of the equipment that the groups are using is the same. Group 1 decides to improve the electromagnet design by changing the number of D-cells in the circuit. They will test 2 D-cells to see if performance is improved. Group 2 decides to improve the electromagnet design by adding 20 more winds and doubling the thickness of the wire used. 5. Which group has a better experimental design? Why do you think so?