Magnetism is the ability of a material to be attracted by a magnet. It also include the ability for some material to act like a magnet. No doubt youve handled refrigerator magnets. You can see some in Figure 1.28. You probably know they stick to a metal refrigerator. This is what holds your homework up. Maybe your little sisters drawings are hung on the fridge in this manner. Do magnets stick to all materials? Of course not. You have probably checked and they do not stick to other surfaces. They do not stick to wooden doors or glass windows. Wood and glass are not attracted to a magnet. Obviously, only certain materials are attracted to magnets. 
What doesn't a magnet stick to and what are examples of these materials?
Glass materials like glass windows