This song explains how the decay of a radioisotope has a half-life and how to use that half-life to solve decay problems. All music and lyrics copyright 2007 by Mark Rosengarten. All rights reserved. Lyrics: A chunk of rock just sits there, underneath the ground Waiting many eons until it can be found Its aglow not just with hope, but radioactivity Its nuclei decaying with regularity! An ancient scroll lies unsuspected on a desert shore Dunes surround its resting place, will it lie evermore? If its found by humans, it will blow their mind Thanks to carbon-fourteen, its timeless age theyll find! Half-life is defined, in each and every way As the time it takes for half the nuclei to decay From parent nuclei into daughter it will give And who can know when there is only one half-life to live? The half-life I-131 is listed at 8 days So if you have ten grams right now, 5 grams will decay If you go another eight, youll be left with two point five Keep cutting it in half for as long as youre alive! Hop into your time machine to eight days ago Double the ten grams you had, twenty grams will glow Go back a further half-life, back to sixteen days You would have had forty grams of iodine that decays! Half-life is defined, in each and every way As the time it takes for half the nuclei to decay From parent nuclei into daughter it will give And who can know when there is only one half-life to live? Flip a coin into the air, watch it as it sails Will it come up heads, or will it come up tails? Its just like a nucleus, each isotopes chance is half To decay in any given half-life, does that make you laugh? So halve the grams of isotope for each half-life thats gone by Or double grams for each half-life if in the past it lies Find how old the rock is, or how ancient is the scroll Once you find the answer, the story can be told! Half-life is defined, in each and every way As the time it takes for half the nuclei to decay From parent nuclei into daughter it will give And we can never know when theres one half-life to live! Hey, guys! Schrödingers Cat is alive!