Graphite is used in pencils because of its ability to leave gray marks on paper. It was originally thought to be a form of lead.Know More
In spite of the name, lead pencils do not actually contain lead. During the Roman Empire, lead rods were used for writing on papyrus. In the 16th century, a large deposit of graphite was discovered in England; shortly after this discovery, graphite became a common material used for writing. It was originally thought to be a darker form of lead and was therefore given the name "Blacklead" or "plumbagoi."
In the late 1700s, a Swedish chemist determined that graphite was a form of carbon rather than lead. The name of the substance was soon changed to graphite, after the Greek word for "to write."
Ink was commonly used for writing — applied using a device called a "peniculus" — from which the word "pencil" is derived. Early forms of pencils involved a graphite rod wrapped in string and inserted into hollow sticks. Eventually a mixture of graphite and clay was developed that eliminated the need for string and produced a harder substance that could easily be inserted into hollow rods. Altering the ratio of graphite to clay produces variations in the darkness of the markings made by the pencil. Adding other materials such as dye, wax, water or charcoal can produce pencils used for other purposes, including cosmetics and art.Learn more in Atoms & Molecules
Platinum is used to make a variety of substances and consumer goods, including catalytic converters, coins, jewelry and industrial appliances. Platinum is also used in the scientific industry to make basic labware items, such as tools and trays, and is used in the field of medicine to augment and structure devices, such as catheters and pacemakers.Full Answer >
Palladium is mainly used in catalytic converters for vehicles and other machines that have engines. The metal acts as a catalyst and aids in the conversion of harmful pollutants in the engine’s emissions to less harmful substances. This ensures that vehicles adhere to environmental standards that limit the amount of pollution that vehicles can produce.Full Answer >
Metals are used to build bridges, plumb homes and make jewelry, wiring, pans and roofing among many other items. Gates, railings and fences are also made out of metal.Full Answer >
The chemical formula Fe2(SO3)3 is used to represent the compound iron(III) sulfite, which is also known as ferrous sulfite. The compound contains two atoms of iron, three atoms of sulfur and nine atoms of oxygen.Full Answer >