Presentation on theme: "Magnetism It can either be attractive or repulsive."— Presentation transcript:
Magnetism It can either be attractive or repulsive.
Some Magnetic Factoids….. Magnets have two poles, North and South. On a compass, the north pole is North seeking while the south pole is South seeking. This means that the earths North pole is magnetically a south pole, and vice-versa for the earths South pole! The earths magnetic poles are slowly drifting and have flipped in the past…
Some common questions regarding magnetism. Q: What causes magnetism? A: Magnetism is caused by moving (or spinning) charge. Q: Can an atom be magnetic? A: Yes, spinning electrons and /or nuclear spin are magnetic. These properties are utilized in MRIs. Q: So, why arent all materials magnetic if all materials are, after all, made of atoms? A: In certain ferromagnetic materials, groups of atoms, called domains are organized. These domains are groups of atoms whose spinning electrons align, forming a net magnetic field. In a magnet, these domains are aligned with one another resulting in a net magnetic field. In a non-magnetic material, these domains are not aligned.
Some common questions regarding magnetism. Q: Are all metals magnetic? A: No. Aluminum and copper are two common metals which are not magnetic. Q: Since a magnet has two poles, a North and a South, can they be separated? A: So far, No… the poles of a magnet cannot be isolated…that is magnetic monopoles have not been observed by themselves…yet, but sub- atomic research may prove otherwise? The search continues.
Permanent magnet?... Permanent shermanent, what is THAT all about? In a permanent magnet (or hard magnetic material), the domains are difficult to align or dis- align. In a temporary magnet, (or soft magnetic material) the domains are easily aligned or dis- aligned. The alignment of domains can be accomplished by subjecting them to a strong magnetic field. Hammering or heating the domains tends to dis-align them and hence weakens the magnetic field.
Magnetic stuff Q: What are some common magnetic objects? A: Credit cards or any other device with an encoded magnetic strip. Other objects which involve magnets include speakers, motors, generators, solenoids and transformers. Q: What about that feeling I have every time he/she walks by? Thats gotta be magnetism! A: Even though the brains neurons operate with some type of electrical activity, a feeling is not purely magnetic. Bummer, I know. Its still a while before prom!