Six Easy Pieces: Essentials of Physics Flashcards

These flashcards cover the fundamental vocabulary and concepts introduced in Richard Feynman's lectures, spanning atomic theory, thermodynamics, biology, basic physics laws, energy conservation, gravitation, and quantum mechanics.

Atomic Hypothesis

The principle that all things are made of atoms—little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another.

Molecule

A group of atoms tied together in a specific arrangement, such as one oxygen atom and two hydrogen atoms in a water molecule.

Angstrom ($Å$)

A unit of length used to measure the radius of an atom, equivalent to $10^{-8}\,cm$. Atoms are typically $1$ or $2\,Å$ in radius.

Heat

The jiggling motion of atoms; as temperature increases, the movement and volume between the atoms increase.

Crystalline Array

The rigid arrangement of atoms in a solid where every atom has a definite place in an ordered pattern that repeats over long distances.

Evaporation

The process by which individual molecules near the surface of a liquid escape the attraction of their neighbors due to accidental accumulations of extra energy.

Dynamic Equilibrium

A state in a closed system where processes like evaporation and condensation occur at the same rate, resulting in no net change despite constant molecular activity.

Ion

An atom that has either gained extra electrons or lost electrons, resulting in an electrical charge, such as sodium and chlorine ions in salt.

Chemical Reaction

A process where atoms change their partners and combinations to form new molecules, often involving the release or absorption of energy.

Brownian Motion

The perpetual jiggling of tiny particles (colloids) in water caused by the continuous bombardment of atoms.

DNA (Deoxyribonucleic acid)

The 'blueprint' molecule in the cell nucleus, consisting of a double chain of sugar and phosphate groups with four kinds of cross-links (adenine, thymine, cytosine, guanine) that carry instructions for protein manufacture.

Enzymes

Large protein molecules that act as catalysts to control and facilitate specific chemical reactions within a cell.

Scientific Method

A process of understanding nature consisting of observation, reason, and experiment, where experiment is the sole judge of scientific 'truth'.

Electric Field

A condition in space created by a charge that exerts a force on other charges placed within it; it allows for the description of electrical interaction without direct contact.

Electromagnetic Waves

Oscillatory waves carried by the electromagnetic field, categorized by frequency into categories such as radio, television, light, X-rays, and gamma rays.

Uncertainty Principle

A fundamental principle of quantum mechanics stating that the product of the uncertainty of the momentum and the uncertainty of the position is bounded by a small constant: $\Delta x \Delta p \ge \hbar/2$.

Quantum Electrodynamics (QED)

The fundamental theory of the interaction of light and matter, or electric fields and charges, which successfully predicts most electrical, mechanical, and chemical laws.

Photon

A particle-like 'lump' of the electromagnetic field; the quantum version of light waves.

Strangeness ($S$)

A quantum number assigned to subatomic particles (like the lambda or sigma baryons) that is conserved in reactions occurring via nuclear forces.

Baryons

A group of subatomic particles that includes the proton and the neutron, as well as several heavier, unstable particles like the lambda and sigma.

Leptons

A group of subatomic particles that do not interact strongly with nuclei, including the electron, the muon, and the neutrino.

Conservation of Energy

A law stating there is a numerical quantity called energy that does not change despite the manifold changes nature undergoes; it can change form but cannot be created or destroyed.

Gravitational Potential Energy

Energy an object possesses due to its position in a gravitational field, calculated as $\text{weight} \times \text{height}$.

Kinetic Energy

The energy of motion possessed by a moving object, approximately calculated by the formula $K.E. = WV^2/2g$.

Mass Energy

Energy associated with the sheer existence of mass, described by Einstein's formula $E = mc^2$.

Law of Gravitation

Every object in the universe attracts every other object with a force proportional to the mass of each and varying inversely as the square of the distance between them: $F = G \frac{mm'}{r^2}$.

Kepler's Second Law

The observation that a radius vector from the sun to a planet sweeps out equal areas in equal intervals of time, indicating that forces are directed toward the sun.

Probability Amplitude ($\phi$)

A complex number used in quantum mechanics whose absolute square ($|\phi|^2$) gives the probability of an event.