Wooden core electromagnet vs iron core electromagnet?

Answer 1

A coil of wire or a coil in the shape of a cylinder is a typical shape for an electromagnet. The strength of the magnetic field of an electromagnet can be increased significantly if the coil is wrapped around an iron core. This does not happen with nonmagnetic materials such as wood or aluminum or rubber.

The enhancement of the electromagnet is caused by the magnetic properties of iron. The atoms of iron have magnetic properties as a consequence of thier electronic structure. (The cause of magnetism at the atomic level is a complex issue if described in detail and that complexity is beyond this explanation.) In a simplified picture one can say that at the atomic level the iron atoms act like little magnets.

The magnetic characteristics of iron are such that an external magnetic field causes the rearrangement of the electronic structure of the iron at the atomic level and that creates a magnetization in the iron. That magnetizations has its own magnetic field just like a normal permanent magnet. The field created by the magnetization of the material adds to the external field and one gets a stronger magnetic field in and around the iron core.

Answer 2

Because iron is magnetic as pure being. Steel is magnetic, but later.