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Inscribed in microscopic font on the disc are 73 messages, each from a different country, expressing wishes of goodwill and peace.

When the Apollo 11 astronauts landed on the moon in 1969, they left behind a white pouch containing a silicon disc slightly bigger than a silver dollar.(Other semiconductors besides silicon can be used in transistors, as well.) Who knew? Electrons, which are negatively charged, are drawn to the positive charge, allowing them to make the leap across the pure-silicon segment. When the electricity flows, the plate becomes positively charged. To turn the switch to "on," a metal plate, connected to a power source, is placed near the crystal. The trace elements bond with the silicon atoms, freeing up electrons to move throughout the material, according to the University of Virginia.īy creating spaces of unadulterated silicon, engineers can create a gap where these electrons can't flow - like a switch in the "off" position. To make silicon into a transistor, the crystalline form of the element is adulterated with trace amounts of other elements, such as boron or phosphorous, according to Lawrence Livermore National Laboratory. Silicon is used in various ways in solar cells and computer chips, with one example being a metal-oxide-semiconductor field effect transistor, or MOSFET, the basic switch in many electronics. As a semiconductor, silicon is used to make transistors, which amplify or switch electrical currents and are the backbone of electronics from radios to iPhones. But the high-tech stuff is where the element really makes its mark. Silicon is a main ingredient in very low-tech creations, including bricks and ceramics. Berzelius heated silica with potassium to purify silicon, according to the Thomas Jefferson National Accelerator Facility, but today the refinement process heats carbon with silica in the form of sand to isolate the element. Silicon was first isolated in 1824 by Swedish chemist Jöns Jacob Berzelius, who also discovered cerium, selenium and thorium, according to the Chemical Heritage Foundation.