The chances for error in this process are tremendous. In , scientists had another idea. They suggested using light produced by hot krypton as the standard of length. Here is how that standard was developed:. When an element is heated, it absorbs energy from the heat.
The atoms present in the element are in an "excited," or energetic, state. Atoms normally do not remain in an excited state very long. They give off the energy they just absorbed and return to their normal, "unexcited" state.
The kind of light given off is different for each element and for each isotope. The light usually consists of a series of very bright lines called a spectrum. The number and color of the lines produced is specific to each element and isotope. When one isotope of krypton, krypton, is heated, it gives off a very clear, distinct, bright line with a reddish-orange color. Scientists decided to define the meter in terms of that line. They said that a meter is 1,, This standard had many advantages. For one thing, almost anyone anywhere could find the official length of a meter.
All one needed was the equipment to heat a sample of krypton Then one had to look for the reddish-orange line produced. The length of the meter, then, was 1,, This definition for the meter lasted only until Scientists then decided to define a meter by how fast light travels in a vacuum.
This system is even more exact than the one based on krypton The only commercial uses of krypton are in various kinds of lamps. When an electric current is passed through krypton gas, it gives off a very bright light. Perhaps the most common application of this principle is in airport runway lights. These lights are so bright that they can be seen even in foggy conditions for distances up to meters 1, feet. The lights do not burn continuously.
Instead, they send out very brief pulses of light. The pulses last no more than about 10 microseconds 10 millionths of a second. They flash on and off about 40 times per minute. Krypton is also used in slide and movie projectors. Krypton gas is also used in making "neon" lights. Neon lights are colored lights often used in advertising. They are similar to fluorescent light bulbs. But they give off a colored light because of the gas they contain.
Some neon lights do contain the gas neon, but others contain other noble gases. A neon light filled with krypton, for example, glows yellow.
Compounds of krypton have been prepared in the laboratory but do not exist in nature. The synthetic artificial compounds are used for research purposes only. Although neon lights sometimes do include neon, krypton is often the gas used. Toggle navigation. Photo by: OlesiaRu. Discovery and naming By , two members of the noble gas family had been discovered.
Physical properties Krypton is a colorless, odorless gas. It's a bird! It's a plane Chemical properties For many years, krypton was thought to be completely inert. The noble gases used to be called the inert gases, but they have been found to be slightly reactive, forming compounds such as krypton difluoride and xenon tetroxide. Ramsay received the Nobel Prize in Chemistry. Krypton has a variety of uses today: in flashes for high-speed photography, in fluorescent lights in combination with argon, and to make so-called neon signs that have a greenish-yellow light.
Neon itself glows red. Between and , the meter was defined as 1,, What's in a name? From the Greek word for hidden, kryptos. Travers, an English chemist, while studying liquefied air. Small amounts of liquid krypton remained behind after the more volatile components of liquid air had boiled away.
The earth's atmosphere is about 0. The oldest Antarctic ice ever found fell as snow , years ago. Bubbles in the ice trap atmospheric gases as they were when the snow fell, Buizert told Live Science. By measuring the levels of krypton and comparing them to the current atmosphere, researchers can use the known rate of decay of the isotope to determine the ice's age. The krypton measurement technique is only about a decade old, Buizert said.
Because krypton and krypton in general is quite rare in the atmosphere, using the gas for dating requires a lot of material — lbs. The actual sampling of the ice was done only two years before the paper was published, Buizert said. Since then, the technology has improved so much that only 44 lbs. Researchers are now seeking even older ice in Antarctica, hoping to find some dating back as far as 1. These ice samples hold clues about the ancient climate and atmosphere at the time when the snow fell.
Far from the glaciers of Antarctica, krypton has also been used to date amazing old groundwater in the Sahara Desert. A study in the journal Geophysical Research Letters revealed that in certain areas of southwestern Egypt, the groundwater reaching the surface hasn't seen the light of day for 1 million years.
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