An overview about the Traffic light

A traffic light or traffic signal is a signaling machine positioned at a road intersection or pedestrian crossing to point out when it is secure or safe to drive, ride or walk, using a worldwide color code.

The Traffic lights for common vehicles or pedestrians for all time have two main lights, a red one that means stop and a green one that means go. Generally, the red light contains some orange in its hue, and the green light has some blue, to give some support for people with red-green color blindness. In nearly all countries there is also a yellow (or amber) light, which when on and not flashing means halt if able to do so securely. In some systems, flashing amber means that a motorist can go ahead with care if the road is clear, giving way to pedestrians and to other road vehicles that possibly will have priority. A flashing red basically means the same as a regular stop sign. There can be added lights (generally a green arrow or "filter") to approve turns (called a lead light in the U.S., because it is generally leading the main green light). Traffic lights for particular vehicles (like buses or trams) may perhaps use other systems, like vertical vs. horizontal bars of white light.

Different Glass Colors information

The Metallic additives in the glass mix can make various colors. Here cobalt has been added to produce a bluish colored attractive glass Metals and metal oxides are added to glass during its manufacture to change its color. Manganese can be added in small amounts to take away the green tint lent by iron, or in higher concentrations to provide glass an amethyst color.

Similar to manganese, selenium can be used in small concentrations to decolorize the glass, or the higher concentrations to impart a reddish color. Small concentrations of the cobalt (0.025 to 0.1%) will yield blue glass. The Tin oxide with antimony and arsenic oxides make an opaque white glass, first used in Venice to make imitation porcelain. 2 to 3% of the copper oxide produces a turquoise color. Pure metallic copper produces an extremely dark red, opaque glass, which is at times used as a substitute for gold ruby glass. Nickel, depending on the concentration, will produces blue, or violet, or even black glass too.

Adding titanium makes the yellowish-brown glass. Metallic gold, in very small concentrations (around 0.001%), will makes a rich ruby-colored glass, while lower concentrations will makes a less intense red, often marketed as "cranberry". Uranium (0.1 to 2%) can be added to give glass a glowing yellow or green color. Uranium glass is normally not radioactive enough to be dangerous, but if ground into a powder, for example by polishing with sandpaper, and inhaled, it can be carcinogenic. Silver compounds (especially silver nitrate) can make a variety of colors from orange-red to yellow. The way the glass is heated and cooled can notably affect the colors shaped by these compounds. The chemistry concerned is complex and not well understood.

The real facts about Earth

Earth is the third planet from the Sun and the fifth largest of the planet. Earth is the only planet whose English name does not originate from Greek/Roman mythology. The name derives from Old English and Germanic.

Earth, for sure, can be studied without the aid of spacecraft. However it was not until the twentieth century that we had maps of the complete planet. Pictures of the planet taken from space are of significant importance; for instance, they are a huge help in weather prediction and especially in tracking and predicting hurricanes. And they are amazingly beautiful. The Earth's magnetic field and its relations with the solar wind also generate the Van Allen emission belts, a pair of doughnut shaped rings of ionized gas (or plasma) trapped in orbit just about the Earth. The outer belt stretches from 19,000 km in altitude to 41,000 km; the inner belt lies involving 13,000 km and 7,600 km in altitude.

The Earth's surface is extremely young. In the relatively short (by astronomical standards) time of 500,000,000 years or so erosion and tectonic processes destroy and remake most of the Earth's surface and thus eliminate almost all traces of earlier geologic surface history (such as impact craters). Thus the very early on history of the Earth has mostly been erased. The Earth is 4.5 to 4.6 billion years old, but the oldest recognized rocks are about 4 billion years old and rocks older than 3 billion years are rare. The oldest fossils of existing organisms are less than 3.9 billion years old. There is no evidence of the critical period when life was first getting in progress.

The Earth's atmosphere is 77% nitrogen, 21% oxygen, with draws of argon, carbon dioxide and water. There was perhaps a very much larger amount of carbon dioxide in the Earth's atmosphere when the Earth was first created, but it has since been nearly all incorporated into carbonate rocks and to a smaller extent dissolved into the oceans and consumed by living plants. Plate tectonics and biological processes now keep a repeated flow of carbon dioxide from the atmosphere to these various "sinks" and back over again. The small amount of carbon dioxide occupant in the atmosphere at any time is very important to the maintenance of the Earth's surface temperature through the greenhouse effect. The greenhouse effect raises the average surface temperature regarding 35 degrees C above what it would if not be (from a frigid -21 C to a comfortable +14 C); without it the oceans would freeze and life as we know it would be impossible.