Half-Lives
Post Reply
 
Thread Rating:
  • 0 Votes - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
03-04-2011, 08:34 AM
Half-Lives
How did scientists discover the length of half-lives? How do they know that X element has a half life of y number of thousands of years? It's all peer reviewed and I trust the process, don't see me as trying to say my ignorance is an argument against it, but I'd really like to remedy that ignorance. Tongue

"It does feel like something to be wrong; it feels like being right." -Kathryn Schulz
I am 100% certain that I am wrong about something I am certain about right now. Because even if everything I stand for turns out to be completely true, I was still wrong about being wrong.
Visit this user's website Find all posts by this user
Like Post Quote this message in a reply
[+] 1 user Likes ebilekittae's post
03-04-2011, 11:10 AM
RE: Half-Lives
Becquerel discovered phosphorescence in 1896 using uranium salt and later learned that there was a decay caused by radiation, later from this Rutherford came up with an equation for the decay which was seen as universal. And then through the law of large numbers the randomness of specific decay is lost through long periods. Scientists over the years studied many objects with known creation dates and studied the levels of radiation within them. The researchers of the 1800s were very helpful in determining half life because they commonly used radioactive substances, and gave many good samples for the later researchers.

It started with studying smaller half life radioactive material and eventually they would find a point when that radiation ceased, and that then became a basis of studying the next larger ones and so on. It was a gradual determination of how long each radioactive isotope lasted from the fewest to the longest in spans of years. Had they not had experience with radiactive materials that lasted a small amount of time they never would have come up with how many thousands of years some last.

I'm not a non believer, I believe in the possibility of anything. I just don't let the actuality of something be determined by a 3rd party.
Find all posts by this user
Like Post Quote this message in a reply
[+] 2 users Like Lilith Pride's post
03-04-2011, 11:23 AM
RE: Half-Lives
I just wrote out a page trying to explain half life. Realized how confusing my explanation was, so deleted it. UGH. I am neither a scientist nor a writer!!

The Greatest Show on Earth has an excellent, easy to understand explanation. I suggest you read that to gain a good understanding of the basics.

[Image: StarkLord01.gif]
Find all posts by this user
Like Post Quote this message in a reply
[+] 1 user Likes Stark Raving's post
03-04-2011, 09:32 PM
RE: Half-Lives
(03-04-2011 08:34 AM)ebilekittae Wrote:  How did scientists discover the length of half-lives?

Observation of some radioactive elements with shorter half-lives allowed them to figure out that all elements undergoing radioactive decay do so in accordance with an exponential function:

N(t) = n*(.5)^(t/h)

N(t) is the amount of the original element left after time t.

n is the original amount of the decaying substance.

h is the half-life of the element.

Once you know this, finding out the half-life of any given element is simple. All you have to do is take a sample of something containing the element in question. From this sample, you can find both N(t) and n: N(t) is just the amount of the element still there, and n is N(t) plus however much of the stuff that it decays into is present. Then all you have to do is watch the sample for a little and measure its decay. Even if there is only a small amount of decay, you can work out h from that. It's all just algebra.

"Sometimes it is better to light a flamethrower than to curse the darkness."
- Terry Pratchett
Visit this user's website Find all posts by this user
Like Post Quote this message in a reply
[+] 1 user Likes Unbeliever's post
03-04-2011, 09:59 PM
RE: Half-Lives
I would assume that it would be a case of watching an element for a short period of time and then working out a number based on how much decay has occurred in the short time.

Jesus Jumping Christ on a traction engine wearing a kilt and eating a marmite sandwich!!!
Visit this user's website Find all posts by this user
Like Post Quote this message in a reply
04-04-2011, 04:16 AM
RE: Half-Lives
Thanks a ton for your explanations! The mentioning of the Law of Large Numbers made it click a lot better for me! I'll also see what I can do about getting the Greatest Show on Earth!

"It does feel like something to be wrong; it feels like being right." -Kathryn Schulz
I am 100% certain that I am wrong about something I am certain about right now. Because even if everything I stand for turns out to be completely true, I was still wrong about being wrong.
Visit this user's website Find all posts by this user
Like Post Quote this message in a reply
05-04-2011, 02:21 PM
 
RE: Half-Lives
Greatest show on Earth is greaaaat. If you have any doubts regarding evolution, it'll surely help. Even if you don't have any doubts, it still provides you with many instances of evolution that you can use to easily explain it to others. It also teaches you about lots of other unrelated things in science that you wouldn't usually just come across, it's a great read.
Quote this message in a reply
08-04-2011, 12:49 AM
RE: Half-Lives
(03-04-2011 11:10 AM)Lilith Pride Wrote:  Becquerel discovered phosphorescence in 1896 using uranium salt and later learned that there was a decay caused by radiation, later from this Rutherford came up with an equation for the decay which was seen as universal. And then through the law of large numbers the randomness of specific decay is lost through long periods. Scientists over the years studied many objects with known creation dates and studied the levels of radiation within them. The researchers of the 1800s were very helpful in determining half life because they commonly used radioactive substances, and gave many good samples for the later researchers.

It started with studying smaller half life radioactive material and eventually they would find a point when that radiation ceased, and that then became a basis of studying the next larger ones and so on. It was a gradual determination of how long each radioactive isotope lasted from the fewest to the longest in spans of years. Had they not had experience with radiactive materials that lasted a small amount of time they never would have come up with how many thousands of years some last.
Holy Smokes! I had no Idea you were a scientist! Nice Lilith!

The Beauty of The Scientific Method , is the Anticipation of a Better Explanation.
Find all posts by this user
Like Post Quote this message in a reply
08-04-2011, 09:25 PM
RE: Half-Lives
I'm a scientist? 0_0!!!!!!!

But I only get $10 an hour damn I really should be getting paid more then.

I'm just your average smart person with kind of awkward living situation. =p

I'm not a non believer, I believe in the possibility of anything. I just don't let the actuality of something be determined by a 3rd party.
Find all posts by this user
Like Post Quote this message in a reply
08-04-2011, 09:36 PM
RE: Half-Lives
You really should get more exposure to radiation Lillith. It might help with that tail-situation of yours. Tongue

I want to rip off your superstitions and make passionate sense to you
Find all posts by this user
Like Post Quote this message in a reply
Post Reply
Forum Jump: