ELi5 | SM on Instagram: "The science behind why steel becomes magnetic when forged in the direction of Earth's magnetic field is rooted in what scientists call thermoremanent magnetization (TRM). When steel is heated up until it glows, its tiny internal “compasses” (called magnetic domains) get shaken up and lose any alignment they had. As the steel cools back down while still inside a magnetic field like Earth’s, shaking the iron (by forging) while it cools helps lock those iron crystals into p