Currents move the tectonic plates.(One word answer)​

Renaldo and nasreen build an electromagnet by wrapping a wire around a nail and connecting the wire to both terminals of a battery. when they test the electromagnet, it can pick up 6 paper clips. their teacher wants all groups to pick up at least 10 paper clips. what could renaldo and nasreen do to increase the number of paper clips their electromagnet picks up?