Explain how scientists use radioactive dating to approximate a rock's age.
2007-01-03 08:07:26 · 6 answers · asked by Mark W 1 in Science & Mathematics ➔ Astronomy & Space
Radiocarbon dating is used to determine the age of substances that are rich in carbon (i.e. plant and animal fossils).
Basically, all living things on our planet have just about the same amount per-mass of a very-slightly radioactive element called Carbon 14 (C14). Once that living thing dies, however, the amount of C14 starts to decay at a rate of half every 5730 years. So, after 5730 years, a fossil would have half the amount of C14 as a living organism of the same size. After 11460 years, a fossil would have 1/4, and so on...
In 1949, it was discovered that we could measure the amount of C14 in a fossil from the very-slight radiation it produces as it decays. From the measure of the amount of C14, and the known half-life of that element, we can pretty accurately determine the age of a fossil.
2007-01-03 08:27:27 · answer #1 · answered by Jay E. 3 · 0⤊ 0⤋
Radioactive dating measures the proportion of Carbon 14 isotope with respect to regular Carbon 12. Carbon 14 is radioactive and decays into Carbon 12 every so many years. By measuring the ratio of C14 to C12 one can figure out how long C14 has been decaying and therefore how old the rock is.
2007-01-03 09:48:46 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Lets say you have a galena crystal in rock. It is formed from pure lead and sulfer. We know it is pure becuase it would not form in this crystal if it wasn't. It forms the crystal with pure Lead. The lead has some radioactive isotopes which degrades to other elements. There is a known rate of degradation and by comparing the exact quantities of the lead and new daughter element, you can calculated the date the crystal (rock) formed.
2007-01-03 08:14:55 · answer #3 · answered by JimZ 7 · 1⤊ 0⤋
Radioactive substances decay with a half life. That means every x amount of years, there is half the amount of radioactive whatever there.
2007-01-03 08:19:32 · answer #4 · answered by Roman Soldier 5 · 0⤊ 0⤋
Please try a Yahoo Search: radioactive dating
for the answer to your question.
2007-01-03 08:15:51 · answer #5 · answered by kearneyconsulting 6 · 0⤊ 0⤋
I think it's a bull****. Those guys just make up stuff to keep their jobs.
2007-01-03 08:13:49 · answer #6 · answered by DeborahDel 6 · 1⤊ 3⤋