Blaise Pascal (1623 – 1662)
Pascal’s Law
NARRATOR: We remember you for your contributions to physics and mathematics, but I would like to ask how you developed the law of pressures.
PASCAL: While working on air, I did a lot of experiments where I used pipes, syringes, bellows, and siphons with a variety of liquids, including quicksilver (mercury). I proved that vacuum existed.
NARRATOR: Great!
PASCAL: In 1647, I had written a small pamphlet on the subject entitled New Experiments with the Vacuum. It led me to dispute the number of scientists who, like Descartes, did not believe in a vacuum. He was so angry with me that he even remarked that I had too much vacuum in my head.
NARRATOR: Yeah.
PASCAL: Anyways, during this period, I conducted various experiments. In one of them, I inserted a long vertical tube into a barrel filled with water. When water was poured into the vertical tube, the barrel burst.
I realized that when we apply pressure to an enclosed fluid (gas or liquid), it will be transmitted equally in all directions through the liquid, regardless of the shape of the container.
NARRATOR: This is what is known as Pascal’s Law.
PASCAL: Yes. I knew that this property of fluids, could be employed in a useful manner.
NARRATOR: And it did. Your works led to development of syringe, hydraulic press, hydraulic brakes, straws etc.
PASCAL: Really!
NARRATOR: Yes.