Is there something special about the halfway point? Does the decay happen at a steady pace or exponentially?
In: 910
Because a full life would be infinity !
You misunderstand what a half-life is. It isn’t ‘how long something lives, divided by two’.
It is a measure of a specific form of decay (originally radioactive decay but it could be anything that loses stuff in the same way).
The ‘same way’ is that, however much stuff you start with, it always takes a fixed time for the quantity of it to halve.
So, if you have a bag of 1000 potatoes and after 100 days, 500 of them have rotted away, and then after a further 100 days, 250 of those remaining 500 have rotted away, and after a furthet 100 days, 125 have rotted away, so that count-versus-time looks like this:
0 1000;
100 500;
200 250;
300 125;
400 62.5;
500 31.25
then you could say that this item has a half life of 100 days.
I’m not claiming that this really works like this for root crops but, if it did, you could legitimately use the ‘half life’ to describe it
As I said, it’s normally used to describe radioactive particles decaying into something else.
This is called an ‘exponential’ decay, meaning that the speed of decay is proprtional to how many there are.
You can see in the above that we get into decimal fractions quite easily. It’s not clear how this translates to the subatomic world, but it illustrates how something decaying like this will, theoretically, never drop to zero. That is what I meant by ‘full life being infinite’.
You don’t have to use half-life, you could use ‘quarter life’ or ‘one tenth life’. Nobody does this, however, because other people wouldn’t know whether you meant ‘a quarter have decayed’ or ‘ a quarter remain’. There is obviously no such ambiguity with ‘half’.
Half lives of radioactive elements can vary from below nano seconds to above milliions of years.
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