How Does Magnetic Putty Work?
If you think regular silly putty is a gooey ball of fun, you will love magnetic putty. Magnetic putty becomes magnetic when iron oxide particles are added to silly putty. The iron oxides magnetize the putty making it a million times more fun and entertaining than regular putty. When magnets are within range of the influence of its magnetic field, the putty will slowly swallow them. Because the magnetic field of the putty is strongest at the center of the blob, the magnets are engulfed. The putty slowly sucks magnets in until they reach the strongest point of the magnetic field.
The Origins of Silly Putty
During World War II, rubber was difficult to come by as Japan conquered rubber-producing countries. So, the government sponsored research to develop a substitute for rubber. Rubber was a much needed commodity during the war to produce materials such as tires, gas masks, and boots for soldiers. In 1943, James Wright is credited with the discovery of silly putty after he combined boric acid with silicone oil. The result of the reaction between the acid and the oil was silly putty, a gooey substance with various properties. While it did not make an effective substitute for rubber, silly putty can stretch further than rubber and it has a high melting point. It wasn’t until 1949 that silly putty was sold as a toy.
Uses of Magnetic Putty
Later on, some more practical uses for the material were discovered. It can remove stains and act as an eraser. Astronauts even used it during the Apollo mission to hold tools in place in zero-gravity. And when you magnetize putty by adding iron oxide it becomes even more useful and entertaining. According to Introduction to Electricity and Magnetism, magnetic putty is also sometimes used underwater to test pipes, platforms and other structures for damage. If something is difficult to reach, magnetic putty is applied and molded to the object. Then a magnetic field is applied and the iron oxides will position themselves along the field. Once the magnetic putty is dry and ink is applied it is an effective method of magnetic particle inspection (MPI).
If you’re curious about magnetic putty, it’s easy to find cool time-lapse videos or buy it for yourself and conduct your own experiments. When you get your hands on magnetic putty, in order for it to swallow magnets as demonstrated in the videos, you have to use really strong magnets with ferromagnetic properties. A regular refrigerator magnet won’t be nearly as effective with magnetic putty as a neodymium magnet. And even with a strong rare-earth magnet, it will take hours for the putty to swallow the magnet. While you’re waiting, you can make even more magnetic putty with this DIY tutorial from a previous blog post!