Question

Changing the current changes the "what" of an electromagnet

Answer 1

You take one spring winding on the one rod like iron rod. this winding iron rod called coil. when you give electric supply to both pole on that rod then that rod or coil produce one electro magnetic field. is called electro magnetism ..... this coil called electromagnet...

Answer 2

An electromagnet is only magnetic when there's current going through
the wire.  If there's no current flowing, then the electromagnet is just a
lump and doesn't attract anything.

The strength of the electromagnet depends on the amount of current
that's flowing through the coil of wire around it.

Changing the current immediately changes ==> the magnitude of the
magnetic field, ==> the strength of the electromagnet, and what it's
able to pick up.