Boyle’s Law
Year of Discovery: 1650
What Is It? The volume of a gas is inversely proportional to the force squeezing it.
Who Discovered It? Robert Boyle
Why Is This One of the 100 Greatest?
The concept Robert Boyle discovered (now called Boyle’s Law) laid the foundation
for all quantitative study and chemical analysis of gasses. It was the first quantitative formula to describe the behavior of gasses. Boyle’s Law is so basic to understanding chemistry
that it is taught to every student in beginning chemistry classes.
A genius experimenter, Boyle also proved that gasses were made of atoms—just like
solids. But in a gas, the atoms are spread far apart and disconnected so that they can be
squeezed tighter. Through these experiments Boyle helped convince the scientific world
that atoms existed—an issue still debated 2,000 years after their existence was first proposed by Democritus in 440 B.C.
How Was It Discovered?
Robert Boyle was the son of an earl and a member of the British Scientific Society.
During a 1662 society meeting, Robert Hooke read a paper describ ing a French experiment
on the “springiness of air.” The characteristics of air were of great interest to scientists in the
seventeenth century.
French scientists built a brass cylinder fitted tightly with a piston. Several men pushed
down hard on the piston, compressing the air trapped below. Then they let go. The piston
sprang back up, but not all the way back up. No matter how often the French tried this experiment, the piston never bounced all the way back up.
The French claimed this proved that air was not perfectly springy. Once compressed, it
stayed slightly compressed.
Robert Boyle claimed that the French experiment proved nothing. Their piston, he
said, was too tight to bounce all the way back up. Others argued that, if they made the piston
looser, air would leak around the edges and ruin the experiment.
Boyle promised to create a perfect piston that was neither too tight nor too loose. He
also claimed that his perfect piston would prove the French wrong.
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