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end of the spectrum are the reds and oranges. These gradually shade into yellow, green, blue, indigo and violet. The colors have different wavelengths, frequencies, and energies. Violet has the shortest wavelength in the visible spectrum. That means it has the highest frequency and energy. Red has the longest wavelength, and lowest frequency and energy. LIGHT IN THE AIR Light travels through space in a straight line as long as nothing disturbs it. As light moves through the atmosphere, it continues to go straight until it bumps into a bit of dust or a gas molecule. Then what happens to the light depends on its wave length and the size of the thing it hits. Dust particles and water droplets are much larger than the wavelength of visible light. When light hits these large particles, it gets reflected, or bounced off, in different directions. The different colors of light are all reflected by the particle in the same way. The reflected light appears white because it still contains all of the same colors. Gas molecules are smaller than the wavelength of visible light. If light bumps into them, it acts differently. When light hits a gas molecule, some of it may get absorbed. After awhile, the molecule radiates (releases, or gives off) the light in a different direction. The color that is radiated is the same color that was absorbed. The different colors of light are affected differently. All of the co

d after Lord John Rayleigh, an English physicist, who first described it in the 1870's.) WHY IS THE SKY BLUE? The blue color of the sky is due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by t

As you look closer to the horizon, the sky appears much paler in color. To reach you, the scattered blue light must pass through more air. Some of it gets scattered away again in other directions. Less blue light reaches your eyes. The color of the sky near the horizon appears paler or white.

An aircraft is a vehicle which is able to fly through the Earth's atmosphere or through any other atmosphere. Rocket vehicles are not aircraft if they are not supported by the surrounding air. All the human activity which surrounds aircraft is called aviation.

Heavier-than-air aircraft must find some way to push air or gas downwards, so that a reaction occurs (by Newton's laws of motion) to push the aircraft upwards. This dynamic movement through the air is the origin of the term aerodyne. There are two ways to produce dynamic upthrust: aerodynamic lift, and powered lift in the form of engine thrust. Aerodynamic lift is the most common, with aeroplanes being kept in the air by the forward movement of wings, and rotorcraft by spinning wing-shaped rotors sometimes called rotary wings. A wing is a flat, horizontal surface, usually shaped in cross-section as an aerofoil. To fly, the wing must move forwards through the air; this movement of air over the aerofoil shape deflects air downward to create an equal and opposite upward force, called lift, according to Newton's third law of motion. A flexible wing is a wing made of fabric or thin sheet material, often stretched over a rigid frame. A kite is tethered to the ground and relies on the speed of the wind over its wings, which may be flexible or rigid, fixed or rotary. With powered lift, the aircraft directs its engine thrust vertically downwards. The initialism VTOL (vertical take off and landing) is applied to aircraft that can take off and land vertically. Most are rotorcraft. Others, such as the Hawker Siddeley Harrier, take off and land vertically using powered lift and transfer to aerodynamic lift in steady flight. Similarly, STOL stands for short take off and landing. Some VTOL aircraft often operate in a short take off/vertical landing regime known as STOVL. A pure rocket is not usually regarded as an aerodyne, because it does not depend on the air for its lift (and can even fly into space), however many aerodynamic lift vehicles have been powered or assisted by rocket motors. Rocket-powered missiles which obtain aerodynamic lift at very high speed due to airflow over their bodies, are a marginal case.

The forerunner of the aeroplane is the kite

The Top Rock is a combination of steps done while standing up. This is the entry dance that Bboys and Bgirls use to start their set. These steps are done before you do a power set or before you go down to the floor. This is the breaker's chance to show how well he or she can rock the beat and/or make gestures to intimidate their opponent

The foundational footwork sequence. Although many variations exist that either add or subtract steps in the sequence, the 6-step is the most basic form of downrock.

A Power Move is any type of move in Bboying which requires spinning and/or rotating in a way that can be done so in multiple rounds. All Power Moves (or series of a type of Power Move) can be connected in combos to form a "Power Combo". Breakers that use mostly Power combos in there sets are commonly known as "Power Heads". Example: Flare-Air Flare-Elbow Air Flare-Air Flare-1990...etc Or-Air Flare 1.5-Babymill-Windmill-Swipe-Windmill-Halo-Headspin...etc The possible number of combinations are endless and only limited by stamina, strength and imagination. In 2002 The Guinness Book of World Records began tracking number of power move rotations for their world record standings. At that time Canadian Gregory Burbidge broke records for Air Flare, Headspins, and Elbow Airflares. American Lauren Jacob held the record for Chair Flares. American Laura Derrick held the record for Tappingmills. Nicole Jones (nationality unknown) held the record for Munch Airflares. In 2004 Guinness removed these titles from their records. At the time Gregory Burbidge was the only one who still held records from the original group.

Remember the rhyme: "Red sky at night, sailor's delight; Red sky at morning, sailors take warning." Look for any sign of red in the sky (not a red sun); it will not be a bold orange or red the majority of the time, but that depends a little on where you live. Sailor's delight If you see a red sky during sunset (when you're looking to the west), there is a high pressure system with dry air that is stirring dust particles in the air, causing the sky to look red. Since prevailing front movements and jet streams weather usually move from west to east (see Tips), the dry air is heading towards you.

Check the grass for dew at sunrise. If the grass is dry, this indicates clouds or strong breezes, which can mean rain. If there's dew, it probably won't rain that day. However, if it rained during the night, this method will not be reliable.

Scientists made an alarming discovery in the 1980s: The average surface temperature on Earth is slowly increasing. This trend is known as global warming. It is believed to be caused by an increase in the amounts of certain gases in the atmosphere. Greenhouse Effect To understand global warming, it helps to first understand something called the greenhouse effect. A greenhouse is a glass house in which plants grow. The glass lets light in and at the same time keeps heat from getting out. This trapped heat keeps the plants warm even when it is cold outside. Likewise, Earth's atmosphere traps energy from the sun. Carbon dioxide and other gases—called greenhouse gases—in the air do this trapping. Without these gases too much heat would go back into space, and living things could not survive. However, as more greenhouse gases get into the air, they also trap more heat. This leads to global warming.