Electric motors, computers, even super-speed trains all use magnets. Fun to play with as a kid or even an adult, the mystery of magnets is an interesting study subject. Magnets attract certain things, repel others and are a necessary component to many of the items we use in daily life. The question of what objects are attracted to magnets produces some surprising results.
Iron, nickel, cobalt and some steels are strongly attracted to magnets. These are ferrous metals, or metals that are both permeable and contain high levels of iron particles. The mechanism for making a metal attractive to magnets or not is the situation of the atoms in the metal itself. Some will realign when placed in a magnetic field and swing in its direction, creating an attraction. Other metals have very fixed atoms that will not be affected.
Certain minerals have attractions to magnetism, some weak, some very strong. Platinum often has a magnetic attraction usually due to ferrous impurities. Hematite and franklinite display weak magnetic attractions. Lodestone, another name for magnetite, is a highly magnetic mineral, which itself is generally magnetic, hence the name magnetite. A material of interest due to its surprising attraction to magnets is some types of black sand, which is actually crushed magnetite. In highly volcanic areas this sand can be attracted to magnets through liquid, a process that is highly useful in some gold-mining methods, as it pulls impure magnetic sand away from the gold.
Magnets can attract dollar bills, liquids, particles from your breakfast cereal, even strawberries if the magnet is strong enough. The reason for this is the objects contain particles of ferrous material, often iron, that is attracted to the magnet. Ink in a dollar bill for instance, has iron particles. Breakfast cereal is often fortified with iron, that can leave small particles which will stick to a magnet. Iron naturally occurs in many things such as some liquids or even vegetation, but it takes a very strong magnet to attract the tiny particles in some things and see it in action.
Those who are lucky enough to view this light show in the northern night sky may not realize that the action is the result of magnetism. The Earth itself is surrounded by a magnetic field and is in essence a giant magnet due in part to its molten iron core. The magnetic field around Earth attracts particles, such as those from the solar wind, which interact with the magnetic field and cause the energy we call the Northern Lights.