Because most watches lack a striking mechanism, such as a bell or gong to announce the passage of time, they are properly designated as timepieces, rather than clocks.
WikipediaWednesday, December 27, 2006
A watch
A agenda
Google was co-founded by Larry Page and Sergey Brin, and was first incorporated as a privately held company on September 7, 1998. Eric Schmidt is Google's chief executive officer, after Larry Page stepped down.
WikipediaA match
There are two main types of matches: safety matches, which can only be struck against a specially-prepared surface, and strike-anywhere matches, for which any sufficiently rough surface can be used.
Note: Match-type compositions may also be used to produce electric matches, which are fired electrically. These items do not rely on the heat of friction.
WikipediaGlass
Glass is a biologically inactive material that can be formed into smooth and impervious surfaces. Glass is brittle and will break into sharp shards. These properties can be modified or changed with the addition of other compounds or heat treatment.
Common glass contains about 70-72 weight % of silicon dioxide (SiO2). The major raw material is sand (or "quartz sand") that contains almost 100% of crystalline silica in the form of quartz. Although it is an almost pure quartz, it may still contain a small amount (< 1%) of iron oxides that would color the glass, so this sand is usually enriched in the factory to reduce the iron oxide amount to < 0.05%. Large natural single crystals of quartz are purer silicon dioxide, and upon crushing are used for high quality specialty glasses. Synthetic amorphous silica (practically 100% pure) is the raw material for the most expensive specialty glasses.
Wikipedia
A stove
There are many types of stoves. A kitchen stove is used to cook food, and refers to a device that has both burners on the top (also known as the cooktop or range or, in British English, the hob) and, often, an oven. A cooktop just has burners on the top and is usually installed into a countertop. A drop-in range has both burners on the top and an oven and hangs from a cutout in the countertop (that is, it cannot be installed free-standing on its own).
In industrial usage, stove may refer to the place where fuel is combusted before being fed to a large heat consumer such as an open hearth furnace.
A freezer
Domestic freezers can be included with a refrigerator or can be stand alone units. Domestic freezers are generally upright units, resembling a refrigerator, or a chest, which resemble an upright unit laid on its back. Many modern freezers come with an icemaker.
WikipediaA refrigerator
Commercial units, which go by many other names, were in use for almost 40 years prior to the common home models. The fact that they operated with toxic ammonia gas systems made them unsafe for home use. Practical household refrigerators were introduced in the 1920s and gained wider acceptance in the 1930s as prices fell and non-toxic, nonflammable synthetic refrigerants, such as Freon or R-12 refrigerants were introduced.
A joke
Jokes are performed either in a staged situation, such as a comedy in front of an audience, or informally for the entertainment of participants and onlookers. The desired response is generally laughter, although loud groans are also a common response to some forms of jokes, such as puns and shaggy dog stories.
WikipediaAlcohol
In general usage, the word alcohol, when used alone, usually refers to ethanol, also known as grain alcohol or (older) spirits of wine. Ethanol is a strongly-smelling, colorless, volatile liquid formed by the fermentation of sugars. It also often refers to any beverage that contains ethanol (see alcoholic beverage). This sense underlies the term alcoholism (addiction to alcohol).
Other forms of alcohol are usually described with a clarifying adjective, as in isopropyl alcohol (isopropanol) or wood alcohol ('methyl alcohol, or methanol). The suffix -ol, appears in the official chemical name of all alcohols.
WikipediaA Post-it note
A paper clip
A hard disk
Hard disks were originally developed for use with computers. In the 21st century, applications for hard disks have expanded beyond computers to include digital video recorders, digital audio players, personal digital assistants, and digital cameras. In 2005 the first mobile phones to include hard disks were introduced by Samsung Group and Nokia. The need for large-scale, reliable storage, independent of a particular device, led to the introduction of configurations such as RAID, hardware such as network attached storage (NAS) devices, and systems such as storage area networks (SANs) for efficient access to large volumes of data.
Wikipedia
Sunscreen
The best sunscreens protect against both UVB (ultraviolet radiation with wavelength between 290 and 320 nanometres), which can cause sunburn, and UVA (between 320 and 400 nanometres), which damages the skin with more long-term effects, such as premature skin aging. Most sunscreens work by containing either an organic chemical compound that absorbs ultraviolet light (such as oxybenzone) or an opaque material that reflects light (such as titanium dioxide, zinc oxide), or a combination of both. Typically, absorptive materials are referred to as chemical blocks, whereas opaque materials are mineral or physical blocks.
Dosing for sunscreen can be calculated using the formula for body surface area and subsequently subtracting the area covered by clothing that provides effective UV protection. The dose used in FDA sunscreen testing is 2 mg/cm². From a sample calculation in a FDA monograph, if one assumes an "average" adult build of height 5 ft 4 in (163 cm) and weight 150 lb (68 kg) with a 32 in (82 cm) waist, that adult wearing a bathing suit covering the groin area should apply 29 g (approximately 1 oz) evenly to the uncovered body area.
Contrary to the common advice that sunscreen should be reapplied every 2–3 hours, research has shown that the best protection is achieved by application 15–30 minutes before exposure, followed by one reapplication 15–30 minutes after the sun exposure begins. Further reapplication is only necessary after activities such as swimming, sweating, and rubbing.[1]
However, more recent research at the University of California indicates that sunscreen needs to be reapplied within 2 hours in order to remain effective. Not reapplying could even cause more cell damage than not using sunscreen at all, due to the release of extra free radicals from the absorbed chemical.[2]
A significant reduction in sun exposure inhibits the production of vitamin D. However, excessive sun exposure has been conclusively linked to some forms of skin cancer and signs of premature aging. Season, geographic latitude, time of day, cloud cover, smog, skin type, and sunscreen all have an effect on vitamin D production in the skin, but fifteen minutes per day of direct exposure to the sun is a generally accepted guideline to follow for optimum vitamin D production. Experts generally recommend taking a fifteen minute walk in the morning or evening without wearing sunscreen to meet this requirement.
WikipediaElectricity
Wikipedia
Light
- Intensity (or amplitude), which is related to the human perception of brightness of the light,
- Frequency (or wavelength), perceived by humans as the colour of the light, and
- Polarization (or angle of vibration), which is only weakly perceptible by humans under ordinary circumstances.
Due to the wave-particle duality of matter, light simultaneously exhibits properties of both waves and particles. The precise nature of light is one of the key questions of modern physics.
Wikipedia
DVD
Video
Video is different than film, which captures a moving image as a sequence of still pictures photographically.
WikipediaA mobile
The telephone
A washing machine
Television
A camera
Glasses
Modern glasses are typically supported by pads on the bridge of the nose and by temples placed over the ears. Historical types include the pince-nez, monocle, and lorgnette.
Lenses were originally made from glass, but many are now made from various types of plastic, including CR-39 or polycarbonate. These materials reduce the danger of breakage and the greater weight of glass lenses. Some plastics also have more advantageous optical properties than glass, such as better transmission of visible light and greater absorption of ultraviolet light. Some plastics have a greater index of refraction than most types of glass; this is useful in the making of corrective lenses shaped to correct vision abnormalities such as myopia, allowing thinner lenses for a given prescription. Scratch-resistant coatings can be applied to most plastic lenses giving them similar scratch resistance to glass. Hydrophobic coatings designed to ease cleaning are also available, as are anti-reflective coatings intended to improve night vision and make the wearer's eyes more visible.
Polycarbonate lenses are the lightest and most shatterproof, making them the best for impact protection. Polycarbonate lenses offer poor optics because of a low Abbe number of 31. CR-39 lenses are the most common plastic lenses, due to their low weight, high scratch resistance and low transparency for ultra violet and infared radiation.
Some glasses are not designed for vision correction. Safety glasses are a kind of eye protection against flying debris or against visible and near visible light or radiation. Sunglasses allow better vision in bright daylight, and may protect against damage from high levels of ultraviolet light.
Wikipedia
A bicycle
First introduced in 19th-century Europe, bicycles now number over one billion worldwide,[1] providing the principal means of transportation in many regions, notably China and the Netherlands. They are also a popular form of recreation, and have been adapted for use in many other fields of human activity, including children's toys, adult fitness, military and local police applications, courier services, and cycle sports.
The basic shape and configuration of the bicycle's frame, wheels, pedals, saddle, and handlebars have hardly changed since the first chain-driven model was developed around 1885[2] , although many important details have since been improved, especially since the advent of modern materials and computer-aided design. These have allowed for a proliferation of specialized designs for individuals who pursue a particular type of cycling.
The bicycle has affected history considerably, in both the cultural and industrial realms. In its early years, bicycle construction drew on pre-existing technologies; more recently, bicycle technology has, in turn, contributed ideas in both old and newer areas.
WikipediaA motorbike
Early motorized bicycles were powered by internal combustion (IC) engines. As electric motors have become lighter and battery storage density higher, the electric motor has recently seen an increase in popularity.
Motorized bicycles are distinguished from motorcycles by being capable of being powered by pedals alone if required. Many motorized bicycles are based on standard bicycle frame designs and technologies, although the modifications to the design to support motorisation may be extensive.
In countries where there is a strong bicycle culture (notably in Asia), the motorised bicycle is particularly popular; in 1996 Shanghai had 370,000 motorized bicycles, and 470,000 other vehicles[1].
Wikipediaa car
As of 2002, there were 590 million passenger cars worldwide (roughly one car for every eleven people), of which 140 million were in the U.S. (roughly one car for every two people). Winkipedia
A house
The house often provides a very permanent residence for a family or for a similar social unit. When occupying a house routinely as a dwelling, English-speaking people may call this building their "home". People may leave their house most of the day for work and recreation, but typically return 'home", to their house, at least for sleeping.
A house generally has at least one entrance, usually in the form of a door or a portal — but some early houses, such as those at Çatal Hüyük, used roofs and ladders for access. Many houses have back doors that open into what some English-speakers call the backyard and others the back garden. When built in appropriate climates, houses may have any number of windows to let in natural sunlight and to provide views of the outside.
WikipediaCentral heating
When combined with other systems in order to control the building climate the whole system may be referred to as HVAC (Heating, Ventilation and Air Conditioning).
Central heating differs from local heating in that the heat generation occurs in one place, such as a furnace room in a house or a mechanical room in a large building (which is not necessarily the "central" geometric point). The most common heat source is through combustion of fossil fuel in a furnace or boiler. The resultant heat is then distributed typically by forced air through ductwork, by water circulating through pipes or by steam fed through pipes. Of increasing use, the heat source may be solar powered, in which case the distribution system is normally by water circulation.
In the UK and much of northern Europe and urban portions of Russia, where air conditioning in homes is rarely warranted due to its temperate climate, central heating is installed in most new housing. It is normally gas fired or, where gas is not readily available (as in Ireland), oil fired systems are used. In the western and southern United States natural gas fired central forced air systems are most common; these systems and central boiler systems are both in use in the far northern regions of the USA. Steam heating systems may be fired by coal, oil or gas and are used in the USA, Russia and Europe primarily for larger buildings. Far less energy efficient[citation needed] and less common are electrical heating systems.
WikipediaA ceiling fan
The toothbrush
Personal computer
Computers take numerous physical forms. Early electronic computers were the size of a large room, consuming as much power as several hundred modern personal computers. [1] Today, computers can be made small enough to fit into a wrist watch and be powered from a watch battery. Society has come to recognize personal computers and their portable equivalent, the laptop computer, as icons of the information age; they are what most people think of as "a computer". However, the most common form of computer in use today is by far the embedded computer. Embedded computers are small, simple devices that are often used to control other devices—for example, they may be found in machines ranging from fighter aircraft to industrial robots, digital cameras, and even children's toys.
Personal Computer by wikipediaThe ability to store and execute programs makes computers extremely versatile and distinguishes them from calculators. The Church–Turing thesis is a mathematical statement of this versatility: Any computer with a certain minimum capability is, in principle, capable of performing the same tasks that any other computer can perform. Therefore, computers with capability and complexity ranging from that of a personal digital assistant to a supercomputer are all able to perform the same computational tasks so long as time and storage capacity are not considerations.
Computer by wikipedia