Monday, May 21, 2012

Refrigerator Magnets


How many time has it happened that you came home and find magnets stuck to your door.  Instead of throwing them away or immediately putting them on your fridge , lets try and learn something about them. Here is a short, easy and fun-to-do scientific experiment with refrigerator's magnets. For our experiment we need two magnets and we will try to stick them together in different ways.

Watch the video to understand what we are going to do and then read the explanations





Try and repeat the experiment shown in the video. Put the magnets together and try to slide one of them up and down. There can be three possibilities:
1) The magnet will slide smoothly
2) The magnet will jump and make a noise
3) The magnets will not hold very well

If the magnets do not hold well, turn one of them 90 degrees and try again, than you will have either option 1 or 2 depending on the direction you choose to slide the magnet (up-down or left-right). Change the direction of sliding and the direction of one of the magnets until you encounter all three possibilities given above.


So why is this? A full explanation of magnetism will require to go into a detailed explanation about magnetic fields and is really unnecessary. We will focus just on remembering that a magnet has its end referred to as the north and south poles. When a north pole is attached to a south pole, the magnets will pull each other, but when attempting to attach a north side to a north side, the magnets will reject each other.
The refrigerator magnets have indeed the two poles but the poles are lined out one next to the other, like columns, within the magnets. Look at the illustration below to see how it works.
Refrigerator Magnet
Refrigerator Magnet is built from strips of North and South next to each other
So when we attached our refrigerator magnets in a way that a north meets south, they  attach strongly. In one direction (for example: up-down) we can slide them with ease, since even if we slide them, the south pole is still on a north pole, but when we try to slide them in the other direction (left-right), it happens that the north pole meets another north pole which immediately rejects it until it finds the next south pole, this makes the non-smooth movement and the loud noise.
When the magnets are attached in the other direction, the north poles meet north and south poles all the time. This creates rejection of the magnets and attracts force which more or less eliminates each other and the magnets do not stick, or connect very loosely.



2 comments:

  1. If I may comment on the cultural rather than the scientific aspect of the video, I have never heard of anyone having magnets stuck to their front door. For that matter, I'm not really familiar with magnetic front doors -- around here, most of them are made of wood.

    We do have advertising magnets; they're just not stuck to our doors. We sometimes get them in the mail, sealed inside an envelope. We sometimes we get them in a box of goods such as a new computer. We sometimes get them when a tradesperson performs a job in our home such as fixing a fridge. Do you get them in all those different ways as well?

    For the record, I'm in Adelaide, Australia.

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  2. Hi Adrian. Your comment is very interesting. Here in Israel you get these magnets on doors, and some people ave special doors that the magnets can not attach to. Also you get them in places like wedding which take your picture and give you a magnet as a souvenir. I hoped you liked the little experiment.

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