Many pencils across the world, and almost all in Europe, are graded on the European system using a continuum from H (commonly interpreted as “hardness”) to B (commonly “blackness”), as well as F (usually taken to mean “fineness”, although F pencils are no more fine or more easily sharpened than any other grade. also known as “firm” in Japan[45]). The standard writing pencil is graded HB.[46]
According to Petroski, this system might have been developed in the early 20th century by Brookman, an English pencil maker. It used B for black and H for hard; a pencil’s grade was described by a sequence or successive Hs or Bs such as BB and BBB for successively softer leads, and HH and HHH for successively harder ones.[47]
The Koh-i-Noor Hardtmuth pencil manufacturers claim to have originated the HB standard of gradations, with H standing for Hardtmuth, B for the company’s location of Budějovice, and F for Franz Hardtmuth, who was responsible for technological improvements in pencil manufacture.[48][49]
Insect collecting refers to the collection of insects and other arthropods for scientific study or as a hobby. Because most insects are small and the majority cannot be identified without the examination of minute morphological characters, entomologists often make and maintain insect collections. Very large collections are conserved in natural history museums or universitieswhere they are maintained and studied by specialists. Many college courses require students to form small collections. There are also amateur entomologists and collectors who keep collections.
A currency (from Middle English: curraunt, “in circulation”, from Latin: currens, -entis) in the most specific use of the word refers to money in any form when in actual use or circulation as a medium of exchange, especially circulating banknotes and coins.[1][2]A more general definition is that a currency is a system of money (monetary units) in common use, especially in a nation.[3] Under this definition, US dollars, British pounds, Australian dollars, and European euros are examples of currency. These various currencies are recognized stores of value and are traded between nations in foreign exchange markets, which determine the relative values of the different currencies.[4] Currencies in this sense are defined by governments, and each type has limited boundaries of acceptance.
A currency (from Middle English: curraunt, “in circulation”, from Latin: currens, -entis) in the most specific use of the word refers to money in any form when in actual use or circulation as a medium of exchange, especially circulating banknotes and coins.[1][2]A more general definition is that a currency is a system of money (monetary units) in common use, especially in a nation.[3] Under this definition, US dollars, British pounds, Australian dollars, and European euros are examples of currency. These various currencies are recognized stores of value and are traded between nations in foreign exchange markets, which determine the relative values of the different currencies.[4] Currencies in this sense are defined by governments, and each type has limited boundaries of acceptance.
A currency (from Middle English: curraunt, “in circulation”, from Latin: currens, -entis) in the most specific use of the word refers to money in any form when in actual use or circulation as a medium of exchange, especially circulating banknotes and coins.[1][2]A more general definition is that a currency is a system of money (monetary units) in common use, especially in a nation.[3] Under this definition, US dollars, British pounds, Australian dollars, and European euros are examples of currency. These various currencies are recognized stores of value and are traded between nations in foreign exchange markets, which determine the relative values of the different currencies.[4] Currencies in this sense are defined by governments, and each type has limited boundaries of acceptance.
A paintbrush is a brush used to apply paint or sometimes ink. A paintbrush is usually made by clamping the bristles to a handle with a ferrule. They are available in various sizes, shapes, and materials. They may be subdivided into decorators’ brushes used for painting and decorating and artists’ brushes use for visual art.
A flashlight (more often called a torch outside North America) is a portable hand-held electric light. The source of the light is usually an incandescent light bulb or light-emitting diode (LED). A typical flashlight consists of a light bulb mounted in a reflector, a transparent cover (sometimes combined with a lens) to protect the light source and reflector, a battery, and a switch. These are supported and protected by a case.
The invention of the dry cell and miniature incandescent electric light bulbs made the first battery-powered flashlights possible around 1899. Today flashlights use mostly incandescent lamps or light-emitting diodes and run on disposable or rechargeable batteries. Some are powered by the user turning a crank or shaking the lamp, and some have solar panels to recharge a battery.
A flashlight (more often called a torch outside North America) is a portable hand-held electric light. The source of the light is usually an incandescent light bulb or light-emitting diode (LED). A typical flashlight consists of a light bulb mounted in a reflector, a transparent cover (sometimes combined with a lens) to protect the light source and reflector, a battery, and a switch. These are supported and protected by a case.
The invention of the dry cell and miniature incandescent electric light bulbs made the first battery-powered flashlights possible around 1899. Today flashlights use mostly incandescent lamps or light-emitting diodes and run on disposable or rechargeable batteries. Some are powered by the user turning a crank or shaking the lamp, and some have solar panels to recharge a battery.
A ballpoint pen, also known as a biro,[1] or ball pen, is a pen that dispenses ink over a metal ball at its point, i.e. over a “ball point”. The metal commonly used is steel, brass, or tungsten carbide.[2] It was conceived and developed as a cleaner and more reliable alternative to dip pens and fountain pens, and it is now the world’s most-used writing instrument:[3] millions are manufactured and sold daily.[4] As a result, it has influenced art and graphic design and spawned an artwork genre.
