# Radiometric dating activity pennies

*26-Oct-2020 19:25*

And so, we can go ahead and graph our next data point. It's 0.5, of course, so, in here, that's about 0.5, and so that gives us an idea about where our next data point is.

There should be two milligrams left after 14.3 days so that's our point. And we could keep going, but this is enough to give you an idea of what the graph looks like.

So there are four half-lives, so four half-lives here.

Let's say we started with four milligrams of phosphorus-32. The half-life depends on what you're talking about.

So four milligrams, if we wait one half-life, goes to two milligrams. So that would be our answer, because that's four half-lives. And that's the same thing as going four, times 1/2 to the fourth power, which mathematically, is four times one over 16, so that's 4/16, so that's the same thing as 1/4, and so that's 0.25 milligrams.