My purpose is to show that the bacteria content does increase in a water bottle when it is not properly washed between uses. In the summer during swim team, I see my teammates fill the same water bottle every day for the whole season. They do not wash the water bottles as evidenced by the lip-gloss colors that don’t go away. The water bottles are stored in their swim bags with moldy dirty towels or they rattle under the seats of their parents’ cars. Also I am doing this experiment in the winter when the temperatures are cooler and bacterial growth tends to be slower than during the hot summer months. If the bacteria do grow in my experiment, the bacteria growth could be greater during the summer months.