Electric and magnetic fields are two different manifestations of electromagnetism. Electric force fields are caused by positive and negative charges carried by particles like protons and electrons. Magnetic force fields are caused by charges in motion. By observing the shape of iron filings around a bar magnet, students will learn the basic shape of the Earth's dipole magnetic field. If you don't have a vial of iron filings in your classroom, no problem.
Iron filings are easy to find.
In most places you can extract them right from the dirt outside. That's a good topic for classroom discussion. Send an adventurous student to the playground with a container and a magnet. They will love sifting their magnet through the dirt for tiny bits of iron. It takes a few recesses to get a cup.