REFRIGERATOR MAGNET

The 'refrigerator magnet' is an ornament attached to a magnet that is used to post items such as shopping lists or report cards on a refrigerator, or simply to decorate the refrigerator. Refrigerator magnets come in a wide variety of shapes and sizes, including for example, images die-cut to a specific shape or tiny plastic sculptures of fruits. Refrigerator magnets are a relatively popular object of collectors.
The first refrigerator magnet patent was obtained by William Zimmerman of St. Louis Missouri, in the early 1970s. Zimmerman patented the idea of small, colored, cartoon magnets to be used for decorative display and convenience.

Contents

Magnetic polarization

Special purpose refrigerator magnets

External links

Magnetic polarization

Unlike most conventional magnets that have distinct, discrete north and south poles, the flat refrigerator magnets made from composite materials are often constructed with alternating north and south poles on the same surface of the plane; this can be felt by taking two similar (or identical) refrigerator magnets and sliding them against each other with the "magnetic" sides facing each other: the magnets will alternately repel and attract as they are moved a few millimeters. This construction is more effective at keeping the large planar magnet uniformly stuck onto the steel refrigerator than a uniformly-polarized magnet would be. The technical term for this arrangement is Halbach array.

Special purpose refrigerator magnets

Sets containing magnets in the shape of the letters of the alphabet, Colorforms, have been manufactured since at least the 1970's, and marketed as an educational production for young children. In the 1990s, sets of very small magnets printed with individual words became popular; these sets are used to create impromptu ''magnetic poetry''. Relatively strong magnets with hooks are produced for the purpose of hanging oven mits or keys. Magnets that serve as a picture frame are also fairly common. Magnets with notepads or dry erase boards are occasionally produced.

External links

★ Refrigerator Magnets at the Materials Research Science and Engineering Center (University of Wisconsin-Madison) explains how refrigerator magnets stick by means of nanoscale properties of strontium ferrite in Hypalon®.

★ Just letters