glue v. paste

Historically, glue referred to liquid adhesives made from animal connective tissue. Glue is prepared by boiling animal parts that contain collagen (e.g., bones, hides, and hooves) to form gelatin, and adding water. In modern usage, any similar natural or synthetic liquid adhesive can be called glue.

Paste is a thick, soft, wet mixture of flour (or starch) and water used to affix paper or other light materials to surfaces.

obverse v. reverse

40th anniversary Concorde coin with an inlaid piece of the heat shield. Obverse (left) and reverse (right). The obverse of a coin is its front, or ‘heads’ side. The reverse of a coin is its back, or ‘tails’ side.

The obverse often prominently features the head of a head of state. The reverse may contain depictions of important individuals, symbolic animals or objects, historical events, significant buildings or monuments, or other emblematic designs.

The terms obverse and reverse are also used to describe paper money, flags, medals, and works of art.

Wikipedia on obverse v. reverse

basement v. cellar

A basement is an entire floor of a building located partially or completely below ground level. A cellar is an underground room used for storage or shelter (e.g., a root cellar, wine cellar, or storm cellar). Basements are sometimes finished, habitable spaces; cellars often aren’t. A cellar can be constructed as a discrete structure, but a basement is always underneath a building’s ground floor. A cellar may be considered to be a type of basement, or a room within a basement, or the two terms may be used interchangeably.

Wikipedia on basement

incandescent v. fluorescent lights

In an incandescent bulb, electric current passing through a thin filament heats it up and causes it to emit light. To prevent oxidation, the filament is sealed within a glass bulb that is either evacuated or filled with an inert gas.

A fluorescent lamp is a phosphor-coated glass tube filled with mercury vapor. A current causes the vapor to emit ultraviolet light, which is absorbed by the phosphor coating and reradiated as visible light.

• At least 95% of the energy consumed by incandescent light bulbs is given off as heat; typically, only 2 to 3% is converted to visible light. Fluorescent lamps are 4 to 6 times as efficient. To promote the use of more energy-efficient technologies, many countries will be phasing out the sale of incandescent lights over the next several years. Incandescents can contribute to heating in the winter, and fluorescents can reduce cooling costs in the summer.
• In normal use, fluorescent lamps last up to 10 times as long as equivalent incandescent lamps. With frequent switching, fluorescents deteriorate rapidly.
• Fluorescents are more complicated, and therefore more expensive. They require a current-limiting ballast, without which they would draw too much power and destroy themselves. Larger tubes also need a starter to strike an arc in the mercury.
• Traditionally, fluorescent lamps were primarily used in commercial settings, but the rising availability of compact fluorescents has made them more common in the home.
• Fluorescent lamps are commonly larger than incandescents, and incandescents can be made smaller than fluorescents.
• Bright, small incandescents can create glare; large, diffuse fluorescents don’t.
• Fluorescents tubes can be straight, u-shaped, ring-shaped, or tightly coiled; most incandescents are variations on bulbous or teardrop shapes.
• The color spectrum of fluorescent light can be less pleasant than that of incandescent light, and it may be harder to perceive colors correctly under fluorescent light.
• Incandescents can run from alternating or direct current. Fluorescents almost always run on AC.
• Incandescents turn on instantly; fluorescents may take a moment to start.
• Fluorescent light fixtures can’t be controlled with a standard dimmer switch.
• Some fluorescents lamps may flicker noticeably, produce an audible hum, or generate radio frequency interference.
• Mercury vapor from broken fluorescent bulbs may present a health hazard.
• Fluorescents are dimmer in cold weather.

U.S. Department of Energy on incandescent v. fluorescent lights

bottle v. jar

A bottle is a vessel with a narrow neck used to store liquids. A jar is a vessel with a wide mouth that can hold liquids or solids.

wiseGEEK on bottle v. jar