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Big Bang Theory

Big Bang Theory

A widely accepted theory that describes the origin of the universe, stating it began from an infinitely hot and dense singularity and has been expanding for approximately 13.7 billion years.

Nucleosynthesis

The process of creating new atomic nuclei, which occurs during the Big Bang and in stars, leading to the formation of elements.

Big Bang Nucleosynthesis

The formation of light elements, primarily helium and hydrogen, that occurred in the early universe.

Stellar Nucleosynthesis

The process by which heavy elements are formed within stars.

Atomic Model

A theoretical representation of the structure of atoms, with key proponents including John Dalton, JJ Thomson, Ernest Rutherford, and Niels Bohr.

John Dalton

Proposed that atoms are indivisible and combine in fixed ratios to form compounds; considered the pioneer of atomic theory.

JJ Thomson

Discovered electrons and proposed the plum pudding model, where electrons are scattered within a positively charged "pudding."

Ernest Rutherford

Conducted the gold foil experiment, leading to the discovery of the atomic nucleus, which is dense and positively charged.

Niels Bohr

Introduced the planetary model of the atom, suggesting that electrons orbit the nucleus in fixed energy levels or shells.

Atomic Number

The number of protons in an atom, which determines the element's identity and is equal to the number of electrons in a neutral atom.

Mass Number

The total number of protons and neutrons in an atom's nucleus.

Neutrons

Neutral particles in the nucleus of an atom, calculated by subtracting the atomic number from the mass number.

Radioactive Decay

The process by which unstable atomic nuclei lose energy by emitting radiation, including alpha decay, beta decay, and gamma decay.

Alpha Decay

A type of radioactive decay where an alpha particle (helium nucleus) is emitted from the nucleus.

Beta Decay

A type of radioactive decay involving the emission of beta particles, which can be negative (electron) or positive (positron).

Gamma Decay

A type of radioactive decay that releases gamma radiation without changing the identity of the element.

Celestial Motion

The movement of celestial objects, including urinal motion (daily rotation of the Earth) and annual motion (yearly movement of stars).

Geocentric Model

An ancient model of the universe proposed by Claudius Ptolemy, where the Earth is at the center and all celestial bodies revolve around it.

Heliocentric Model

Proposed by Nicolaus Copernicus, this model places the Sun at the center of the universe, with planets, including Earth, orbiting around it.

Kepler's Laws of Planetary Motion

Three laws describing the motion of planets, including elliptical orbits, equal areas in equal times, and the relationship between orbital period and distance from the Sun.

Newton's Laws of Motion

Three fundamental laws describing the relationship between the motion of an object and the forces acting on it, including inertia, acceleration, and action-reaction.

Momentum

The product of an object's mass and velocity, which is conserved in closed systems during collisions.

Elastic Collision

A collision where both momentum and kinetic energy are conserved.

Inelastic Collision

A collision where momentum is conserved, but kinetic energy is not; objects may stick together after the collision.

Reflection

The bouncing back of light when it strikes a surface, such as a mirror.

Refraction

The bending of light as it passes from one medium to another, causing objects to appear displaced.

Absorption

The process by which light is absorbed by a material and converted into other forms of energy, often heat.

Transmission

The passage of light through a material, which can vary in intensity based on the material's properties.

Mechanical Waves

Waves that require a medium (solid, liquid, or gas) to propagate.

Electromagnetic Waves

Waves that can travel through a vacuum and do not require a medium.

Polar Molecules

Molecules with an unequal charge distribution, making them soluble in water.

Nonpolar Molecules

Molecules with an equal charge distribution, which are not easily dissolved in water.

Macromolecules

Large molecules essential for life, including carbohydrates, proteins, lipids, and nucleic acids.