Brownian motion Particulate energy Solids Commentary

Robert Brown, Ludwig Boltzmann, Albert Einstein, Jean Baptiste Perrin physics

Brownian motion

• Scottish botanist Robert Brown,
• examining starch and lipid organelles
• ejected from grains of pollen in water,
• observed a continuous jittery motion.
• The issue was whether energy or atoms
• were pushing the particles around.
• In spite of the work of John Dalton, many physicists
• didn’t believe in atoms and molecules.
• German physicist Ludwig Boltzmann,
• who developed the kinetic theory of gases,
• claimed that what we know as heat was simply
• atoms and molecules moving rapidly.
• Albert Einstein modeled the collective motions
• of particles, focusing first on their diffusion over time,
• then on the measurable quantities, which let him
• predict the sizes and number of atoms in a gas.
• French physicist Jean Baptiste Perrin experimented
• with colloidal suspensions to verify Einstein’s predictions,
• thus settling the century-long dispute
• about Dalton’s atomic theory.

Particulate energy

• Shake atoms up and they get hot.
• Excited, they expand; contract, they emit photons.
• They can hold only so much, take only so much pressure,
• and do only so much work until they come to rest.
• Even the vacuum of empty space
• is believed to have energy, vacuum fluxuations,
• vibrating fields, or virtual particle pairs,
• and thus have mass, which is quantized, but never rests.

Solids

• My fingers on your arm,
• a solid feeling a solid, or softness,
• do not betray the fact that they, or your arm,
• that is, their atoms, are widely spaced
• like distant planets around a sun.