Investigate! Investigate! You are going to investigate how changing the number of coils on an electromagnet changes its strength. You must keep the voltage the same (4 volts). Copy this table to put in your results. What did you discover? Now investigate how changing the voltage changes the strength. (Do not go over 10 volts) Investigate! You are going to investigate how changing the number of coils on an electromagnet changes its strength. You must keep the voltage the same (4 volts). Copy this table to put in your results. What did you discover? Now investigate how changing the voltage changes the strength. (Do not go over 10 volts)