Pasteur's Experiment!

Louis Pasteur designed a procedure to test whether sterile nutrient broth could spontaneously generate microbial life. To do this, he set up two experiments. In both, Pasteur added nutrient broth to flasks, bent the necks of the flasks into S-shapes, and then boiled the broth to kill any existing microbes. If left undisturbed, will the broth in these flasks become cloudy with microbial growth? Click on the correct answer. After the broth had been sterilized, Pasteur broke off the swan necks from some of the flasks, exposing the nutrient broth within them to air from above. The remaining flasks were left intact. What do you predict will happen to the broth in the flask on the left? Click on the correct answer. Over time, dust particles from the air fell into the broken flasks, but in the intact flasks, dust particles remained near the tip of the swan necks. They were unable to travel against gravity into the flasks. The broth in the broken flasks quickly became cloudy, a sign that it teemed with microbial life. However, the broth in the unbroken flasks remained clear. Without the introduction of dust on which microbes can travel, no life arose. Pasteur thus refuted the notion of spontaneous generation.