Scientists can trace the magnetic fields of sunspots using a device called a magnetograph. Magnetic fields act a bit like rubber bands. When you stretch or twist them they can snap back violently. With a rubber band all you get is a hurt finger. When a sunspot magnetic field you can end up with a tremendous solar flare.
Scientists predict when flares are going to happen by looking at their magnetic fields .
When the fields are simple and untangled, like a bar magnet's, flares are unlikely. 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.