The effect of physics on the magnetic size of the electromagnet:

First, with the number of turns of the coil, you can use the wiring method to change the number of coil turns;

Second, with the size of the current through the conductor, through the sliding rheostat can change the current through the conductor, but also by increasing the number of batteries to increase the current;

Third, with or without core, there is a strong magnetic core, when the core is weak magnetic;

4. It is related to the magnetic permeability of the core's soft magnetic material.

5. Related to the cross section of the core.

   The main part of our study is related to the first three articles above. Others are also related to:

   In our daily life, we can also make electromagnets and conduct experiments on our own. The tools we need are wires, nails, and batteries. Using the control variable method can help us make a change, and other kinds of changes, such as : When the research is related to the number of turns, two electromagnets can be connected in series in the circuit to ensure that the current and the core do not change.