[color=#666666][b]The half-life of a substance is defined to be the amount of time it takes for half of ANY AMOUNT of that substance to decay. [br][/b][/color][br][color=#666666]The applet below dynamically illustrates this. [/color] [br][color=#ff00ff][br][b]Feel free to adjust the initial amount (pink point) -- when time [i]t[/i] = 0.[/b][/color][br][color=#1e84cc][b]Feel free to adjust the half-life of the substance (at any time) as well. [/b][/color]