Electromagnets Lab

What I was looking to find out was, how does the battery voltage affect the magnetic field of a magnet? From doing this lab, I learnt that the strength of an electromagnet can easily be changed by changing the amount of electric current that flows through it. In addition, the poles of an electromagnet can even be reversed by reversing the flow of electricity. The magnetic strength is the same for each absolute value, even if the x and y axis poles are different.