someone answered that half life "has nothing to do w/ the amount of time something is alive, it is a measure of how long half of what is in that something stays around" why does half of something metters and not the whole of it ??
2007-01-14 05:15:09 · 11 answers · asked by barvazduck 1 in Science & Mathematics ➔ Biology
i dunno
2007-01-14 05:18:12 · answer #1 · answered by ttony011 3 · 0⤊ 1⤋
The half life is the amount of time it takes for half of something radioactive to decay to a non-radioactive form. For example, in nature, carbon is found in two forms: carbon 12, which is much more common, and carbon 14, which is less common and slightly radioactive. All living things will absorb a certain amount of carbon 14 during their lifespans. When they die, the carbon 14 beings to decay into carbon 12. It takes approximately 7000 years for half of the original amount of carbon 14 to break down to carbon 12. If I found a skeleton that was very old, I could do a test to determine the proportion of carbon 14 to carbon 12, and knowing the half life of carbon 14, I could make a relatively accurate estimate of how old the skeleton is. After 1 half-life, half of the original carbon 14 is left. After two half life, half of the half (one quarter) is left. I hope this helps.
2007-01-14 05:22:40 · answer #2 · answered by Suzanne 2 · 1⤊ 0⤋
Many things, like radioactivity, experience exponential decay, in which the stuff disappears at a rate proportional to the amount of stuff. The result is that the amount of stuff is constantly decreasing, but never reaches zero. This is why we can't state the time it takes for all of it to disappear: there'll always be some of it left. So we use the time for half of it to disappear instead.
2007-01-14 05:28:53 · answer #3 · answered by Steven F 2 · 0⤊ 0⤋
Half life is used for radio isotopes to allow a person to determine how strong the medication is now. With long acting isotopes it is not so important, but with short acting such I131 it is important. It also tells how many years a site may not be used due to radioactive contamination.
2007-01-14 05:20:20 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Half life is the length of time it takes for half of a radioactive isotope to decay. For instance, the half life of a uranium-232 sample is about 69 years.
2007-01-14 05:20:32 · answer #5 · answered by dB 2 · 0⤊ 0⤋
It refers to radioctive decay. Its the amount of time it takes for half the atoms in a sample to decay. Half is used because if all the atoms had decayed, there would no longer be a sample to work with.
2007-01-14 05:18:29 · answer #6 · answered by polk2525 4 · 0⤊ 0⤋
with medication it tells when a medication breaks down in the body. example cipro 500mg half life is 4 hours.... so 4 hours after its in your body 250mg is left..... 4 hours after that 125mg is left and so on. This helps determine how long it should be before the next dose of medication would be given.
2007-01-14 05:19:43 · answer #7 · answered by Anonymous · 0⤊ 0⤋
maybe because without half of it it would be useless without the other half just look at it living half your life without the other half, would make it kinda useless don't u think.
2007-01-14 05:33:08 · answer #8 · answered by jovene_cunningham2000 2 · 0⤊ 0⤋
From what remember they use it to determine a fossil's or ancient things age.
2007-01-14 05:18:34 · answer #9 · answered by Halle Berry 3 · 0⤊ 0⤋
to find out how long an organism lived.
2007-01-14 05:19:28 · answer #10 · answered by eaglesfan123 1 · 1⤊ 0⤋
I half understand your question?
2007-01-14 05:17:50 · answer #11 · answered by Twigward 3 · 0⤊ 1⤋