Louis Pasteur Swan Neck Flask Experiment

Louis Pasteur was a highly regarded biologist, microbiologist and chemist that made some groundbreaking discoveries in his time. He is known for making discoveries that supported the germ theory of disease. One of his most famous experiments was vital in disproving the theory of spontaneous generation.

Pasteur’s Life

Pasteur was born in 1822 in France. He studied philosophy in college and was eventually appointed as a tutored after getting his bachelors. He continued to study mathematics and eventually received his Master of Science degree. He then served as a physics professors. He passed away in 1849.

The Swan Neck Flask Experiment

Louis Pasteur made many groundbreaking discoveries during his time. One of his most famous experiments was the swan neck flask experiment that is regarded as proving instrumental in disproving the theory of spontaneous generation. 

Spontaneous generation was a theory that argued that living organisms could form from nonliving matter. It was believed this was a regular occurrence. To disprove this theory Louis Pasteur filled a swan neck flask with beef broth and boiled it. A swan neck flask has a long winding neck that prevents the contents of the flask from being exposed to air. In his experiment he showed that after boiling the beef broth, no microbes appeared. However if the neck of the flask was broken off, and the contents of the flask exposed to air, then the mixture would turn cloudy and show signs of microbial contamination.

Because the flask that was intact showed no microbes, and the flask that had been exposed to air showed microbes, he concluded that microbes cannot spontaneously generate. His experiment is considered the tipping point which expelled the theory of spontaneous generation from scientific thought.

Sources:
https://en.wikipedia.org/wiki/Louis_Pasteur