The purpose is to enhance the magnetic field - to make it stronger - compared to just using air.
Iron - use a bunch of iron nails, wrapped many times with insulated copper wire, if making your own electromagnet.
Soft iron core
iron
A solenoid is an electromagnet An electromagnet is a solenoid with an iron core
An iron core and wire wound around it
Every thing except a conducting wire, battery and a soft iron core is not needed for making an electromagnet
Iron - use a bunch of iron nails, wrapped many times with insulated copper wire, if making your own electromagnet.
Soft iron core
an electromagnet
iron
An iron core and wire wound around it
electromagnet
A solenoid is an electromagnet An electromagnet is a solenoid with an iron core
a part of the earths structure causes it to act like an electromagnet
That can be a 'solenoid' or an 'electromagnet'.
iron
because exhibits maximum flux density requires small magnetising field exhibits low hysteresis loop