Half-life | Physics | Khan Academy

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Күн бұрын

Half-life is the time required for half of a radioactive sample to decay. Half-life cannot be changed-nuclei cannot be forced to decay faster or slower. Additionally, we cannot predict when an individual nucleus will decay. However, when analyzing a large sample containing many nuclei, half-life allows us to predict how much of the sample will remain after a given amount of time. This is useful for radiometric dating.
Sections:
00:00 - Intro
00:34 - What is half-life?
03:26 - Coin toss analogy
05:50 - Radioactive decay is spontaneous
06:37 - Why care about half-life?
07:20 - Decay graph
08:30 - Radiometric dating
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Пікірлер: 22

@user-pg2zc4oi6r 4 ай бұрын

Clicked cause of the game, stayed out of curiosity. Wasn't dissapointed.

@A_Good_Boy. 4 ай бұрын

do you know? they copied the main place from counter strike half-life game in the current Loki season 2

@Nived_69 2 ай бұрын

@@A_Good_Boy. i thought they just had a copy of the stun baton

@subjectnether959 4 ай бұрын

"Gordon doesnt need to hear all this, he's a highly trained professional."

@UNITEDNATIONSAREAWESOME 4 ай бұрын

Gordon doesn’t need to hear all of this, he’s a highly trained professional

@Mahesh_Shenoy 4 ай бұрын

‘Please, leave me alone until after the experiment!’

@Urstrulyharsha.srk2277 4 ай бұрын

Lol

@ipalomino2182 4 ай бұрын

Nice video, thanks. But how do we know that the half-live of C14 is 5730 years? Radioactivity was discovered on the 19th century, right?

@christinejackson6630 4 ай бұрын

True, but the decay of any radioisotope follows an exponential decay curve as shown at 8:42. So, even if we’ve observed a sample for less than one full half-life, we can measure how much of the parent remains after that time. Then we can extrapolate the rest of the decay curve and determine the radioisotope’s half-life.

@ibraheimsalam4345 4 ай бұрын

Well explained

@CristuelCasto 4 ай бұрын

It's a great game.

@Manigo1743 Күн бұрын

But how do we know that uranium has a half-life of 4.5B years? It is not like we can sit around and wait to see how long it takes for half of it to disappear. Even with a large amount, and waiting for something like 100 years, would it even be noticable?