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How do atoms differ from the indivisible atoms imagined in ancient Greece?
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physics
As conceived by Daniel Bernoulli in Hydrodynamica (1738), gases consist of numerous particles in rapid random motion. He assumed that the pressure of a gas is produced by the direct impact of the particles on the walls of the container.
The ancient Greek concept of the atomos—meaning "indivisible"—posited that atoms were the smallest, solid, and immutable building blocks of matter. Modern atomic theory has fundamentally revised this view, revealing that atoms are complex, divisible structures rather than solid spheres.123
Key differences include:
- Internal Structure: Unlike the solid corpuscles imagined by Democritus, modern atoms consist of a dense, positively charged nucleus surrounded by a cloud of negatively charged electrons.543
- Divisibility: Atoms are not indivisible; they can be split, a process that releases vast amounts of energy. Furthermore, they are composed of smaller subatomic particles, including protons, neutrons, and electrons.143
- Composition: Protons and neutrons themselves are composed of even smaller particles called quarks.2
- Empty Space: While ancient models viewed atoms as solid, modern physics shows that an atom consists largely of empty space, with the nucleus occupying only a minute fraction of the total volume.4
These insights were developed through 20th-century experiments, such as those by Ernest Rutherford, which overturned the notion of the atom as a homogeneous, indivisible particle.523