Doubling Time is the time it takes a population to double at a constant rate of growth. Bacteria, for instance, multiply by division.

One bacterium becomes two. Then two divide into four; the four divide into eight, and so on.

For a certain strain of bacteria, the time for this division process is one minute. If you put one of these bacterium in a bottle at 11:00 p.m., the entire bottle will be full by midnight.

 

When would the bottle be half full?