Here we're going to say that half-life, which uses the variable
Let's consider the radioactive decay of an unknown radioisotope with a half-life of one day. A half-life of one day means that after one day, half of the substance will be gone. Let's say that we're starting out with some unknown isotope. Remember, our isotope here uses
Now one day is allowed to pass, and a half-life, which is equal to a day in this scenario, results in the loss of half of my substance. Now I only have 5 grams left, which is 50%. Another day passes, and I lose another half, leaving me with only 2.5 grams. This means 2 half-lives have passed, and now only 25% remains. Remember, 100% was 10 grams, and now I have only 2.5 grams left.
Another half-life passes, so I lose another half of this 2.5 grams, leaving me with 1.25 grams. Thus, 3 half-lives have passed, and I now only have 12.5% remaining of the original amount I started with. This process can continue, demonstrating how half-life works—it's the amount of time it takes to lose half or 50% of the starting material. This decay continues potentially to a fourth half-life, where I would lose another half of the remaining substance.