Blu-ray Disc (also known as Blu-ray or BD) is an optical disc storage media format. Its main uses are high-definition video and data storage. The disc has the same dimensions as a standard DVD or CD.
The name Blu-ray Disc is derived from the blue-violet laser used to read and write this type of disc. Because of its shorter wavelength (4...
An earthquake is the shaking of the ground caused by an abrupt shift of rock along a fracture in the Earth, called a fault. Within seconds, an earthquake releases stress that has slowly accumulated within the rock, sometimes over hundreds of years.
The size of an earthquake is indicated by a number called its magnitude. Magnit...
A liquid crystal display (LCD) is a thin, flat display device made up of any number of color or monochrome pixels arrayed in front of a light source or reflector. It is often utilized in battery-powered electronic devices because it uses very small amounts of electric power.
Most of us were told somewhere in our educational experience that there are three states of matter--liquid, solid, and gas. The designs of the atom allow atoms to combine in rigid lattices, tumble over each other, or float free away from each other. These balances of charge, buoyancy, gravity, and shape allow matter to have an incredible number of s...
A Bose–Einstein condensate (BEC) is a state of matter of bosons confined in an external potential and cooled to temperatures very near to absolute zero (0 K or -273.15°C). Under such supercooled conditions, a large fraction of the atoms collapse into the lowest quantum state of the external potential, at which point quantum effects...
There are many popular myths concerning black holes, many of them perpetuated by Hollywood. Television and movies have portrayed them as time-traveling tunnels to another dimension, cosmic vacuum cleaners sucking up everything in sight, and so on. It can be said that black holes are really just the evolutionary end point of massive stars. But so...
A Dog Whistle (known as Galton's whistle) is a type of whistle used in the training of dogs and cats. It was invented by Francis Galton. This is discussed quite briefly in his book Inquiries into Human Faculty and its Development (Galton 1883:27). In his discussion (Galton 1883:26-27)of his his experiments to test the range of frequencies th...
Aerogel is the lightest and lowest-density solid known to exist. It is typically 50-99.5% air, yet can hold (theoretically) 500 to 4,000 times its weight in applied force. Aerogel can have surface areas ranging from 250 to 3,000 square meters per gram, meaning that a cubic inch (2.5 cm x 2.5 cm x 2.5 cm) of aerogel flattened-out (again theoreticall...
People with hearing loss may need a hearing aid. A hearing aid is an electronic battery operated device. The hearing aid receives the sound through a microphone. The microphone converts the sound waves to electrical signals. These electrical signals are amplified by an amplifier. The amplified electrical are given to a speaker of the hearing ai...
When the speed of any object exceeds the speed of sound it is said to be travelling at supersonic speed. Bullets, Jets, Aircraft etc. often travel at supersonic speeds. When a sound, producing source moves faster than that of the sound, it produces shock waves. These shock waves carry a large amount of energy. The air pressure variation associat...
The boundaries of the Triangle vary with the author; some stating its shape is akin to a trapezoid covering the Straits of Florida, the Bahamas, and the entire Caribbean island area east to the Azores; others add to it the Gulf of Mexico. The more familiar, triangular boundary in...
A clue to the formation of hailstones is seen when a hailstone is cut in half. Most show an onion-like layering of alternating clear and opaque ice. This layering demonstrates that the stone is built up by coatings of ice successively frozen onto the surface of the hailstone. Each coating evidences a buildup in an environment d...
Thu Apr 10, 2008 12:31 am by 
