Ferromagnetism is a form of magnetism that can be acquired in an external magnetic field and is usually retained in its absence. Thus, ferromagnetic materials like iron and nickel are used to make permanent magnets. This type of magnetism is caused by spinning electrons in the atoms of the material, which act as tiny weak magnets. They align parallel to each other within small regions of the material to form areas of stronger magnetism. What other substances exhibit ferromagnetism?
E. M. Forster
Back in the day
Many believe that the large fireball observed in the sky above Ontario, Canada, and six US states was nothing more than a passing meteor. However, residents of the small town of Kecksburg, Pennsylvania, claim that a car-sized, acorn-shaped object with hieroglyphic-like markings crashed in a nearby wood. The military denied these allegations, but, nearly 40 years later, NASA made what admission regarding the suspicious object?
Born on a day like today
Haber was a German chemist whose work was instrumental in the development of poison gas during WWI. Although he defended gas warfare against accusations that the practice was inhumane, his wife's suicide is believed to have been prompted by his work. Despite Haber's conversion from Judaism and his service during WWI, he was exiled from Germany following the Nazi rise to power. In an ironic twist of fate, the Nazi's used which of Haber's inventions to kill many of his relatives during WWII?