The bacteria took 1 hour and 40 minutes to fill the initial bottle. Explain how it only took 10 minutes to fill 3 additional empty bottles.

Answer:

Because the bacteria growth is exponential, the number of cells doubles at a constant rate. While it took a long time to reach the volume of one bottle starting from a single cell, once the bottle was full, all those cells doubled simultaneously. If the doubling time is 5 minutes, the one full bottle would produce enough cells to fill a second bottle in just 5 minutes. Then, those two full bottles would double again in the next 5 minutes, producing enough cells to fill two more bottles (for a total of four bottles) in only 10 minutes total.