A Guide to Romance

I need an explination SIMPLE method of radioactive dating!?

I need to be able to stand in front of the class and tell them what it is, what it means, and how. The problem is that i cannot find an easy way to explain and understand. im looking for an answer that will explain every part of the definition. thank you! Remember this is for a group of teenagers and so I need to be able to decompose and understand with my classmates. thank you!

The basic principle underlying all methods is that radioactive "parent" disintegrates into a stable element "daughter" element at a constant rate. The decay rate (λ) is the fraction of the initial number of atoms of the parent element, which disintegrate per unit time. Another way of expressing it is the half-life of time (T), which is the period of time required for half the number of "parent" atoms of the element to decay. The relationship between T and λ is T = 0.693 / λ. To use a radioactive element dating, it is essential that λ T or should be known with precision. If, knowing this constant, chemical analysis for the "parent" and "daughter" element is made, the time can be calculated. To minimize sources error, it is often necessary to use the minerals that contain only a tiny proportion of the "parent" and "daughter elements" and therefore the analysis technique to a maximum of precision and accuracy have been made. It should be noted that the decomposition of "Mother" for "daughter" element takes place in May in one step or series of steps. Serious errors will arise if, at any time, any "mother" or via item 'girl' is brought in or removed from the system. The initial presence elements of the "daughter" of non-radiogenic may produce unreliable results. The methods most commonly used are: 1) uranium - Lead 2 isotopes of uranium can be used - U238 yielding Pb206 8 He4 and U235 yielding Pb207 + 7He4. The half-lives of these two processes are 4498 and 713 my respectively. At the beginning of the accumulation of helium has been trying to measure, but as it leaks from the rock, it is not used. Now, the mineral zircon is used instead, because the mineral is highly resistant minute contains traces of uranium and is very low in primary (non-content) radiogenic lead. 2) Thorium-Lead Th232 208Pb yields 6 HE4, half-life of 13,900 m y. Not used as commonly results are rather unstable. 3) Lead-Since Pb207 has six times faster than Pb206, an age can be obtained by comparing, assuming all the Pb207 and Pb206 are radiogenic. 4) Potassium - Argon 11% yield K40 A40, 89% yield CA40, half-lives of these two processes being my 11,850 million and 1470 years respectively. K40 - CA40 system is difficult to use as the cause of the abundance of non-radiogenic Ca. K40-A40 method gives good results, if the materials are chosen carefully, although argon is a gas and tend to escape. 5) Rubidium - strontium SR87 returns Rb87 half-life is about 50,000 Fits My only for very old rocks, because half of the major periods of life. Although neither Rb nor Sr is a common element, the primary contamination by Sr or loss of Rb or Sr system is unlikely. This makes the method reliable enough. 6) Carbon 14 Nitrogen 14 in atmospheric C14 is due to reaction cosmic rays. All agencies are C14 and a constant level is maintained by all agencies. At death, the C14 absorption ceases and its proportion is diminishing constant. Therefore, knowing the initial concentration, the current ratio and the decay constant, a relatively accurate age can be estimated. This method is suitable for relatively new materials, up to 70,000 years. Remember, the radiometric dating methods are improving constantly and no method is perfect. The dates are like train schedules, "subject to change without notice.

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