Nature of Physical Sciences - Vocabulary Flashcards

Vocabulary flashcards covering measurement, thermodynamics, motion, energy, and related physical science concepts from the lecture notes.

Meter

The SI unit of length defined by the distance light travels in vacuum in 1/299,792,458 of a second.

Kilogram

The SI unit of mass; originally defined by the mass of 1 liter of water; now defined by the International Prototype cylinder kept in France.

Second

The SI unit of time; defined by the radiation frequency of the Cs-133 atom: 9,192,631,770 oscillations per second.

Liter

A unit of volume; equal to 1000 cubic centimeters; 1 L of pure water has a mass of about 1 kg.

Mass

The amount of matter in an object; a fundamental quantity that remains constant regardless of location.

Weight

The force of gravity on an object; depends on location; w = mg; not a unit of mass.

Density

Mass per unit volume; units typically g/cm³; water has a density of about 1 g/cm³.

Temperature

A measure of the average kinetic energy of the molecules in a substance; hot vs cold are relative terms.

Thermometer

An instrument that measures temperature, often via expansion of a material.

Thermal expansion

Expansion of a material as temperature increases.

Ice point

0°C at normal atmospheric pressure; reference point for many thermometers.

Steam point

100°C (boiling point of water) at normal atmospheric pressure; reference point for thermometers.

Absolute zero

The lowest possible temperature (-273.15°C); motion of molecules is minimal.

Calorie

The amount of heat required to raise the temperature of 1 g of water by 1°C; 1 cal = 4.186 J.

Food Calorie (kcal)

1 Food Calorie = 1000 calories = 4186 J; energy value used in nutrition.

British Thermal Unit (Btu)

The amount of heat required to raise the temperature of 1 lb of water by 1°F; 1 Btu ≈ 1055 J.

Specific heat

The amount of heat needed to raise the temperature of 1 kg of a substance by 1°C; units J/(kg·°C) or kcal/(kg·°C).

Phase change

Transition between solid, liquid, and gas (melting, freezing, vaporization, condensation, sublimation, deposition).

Latent heat

Energy absorbed or released during a phase change without a change in temperature (e.g., latent heat of vaporization).

Pressure

Force per unit area; SI unit Pa; 1 atm ≈ 1.01×10^5 Pa; commonly 14.7 psi at sea level.

Conduction

Transfer of heat by direct contact between substances; depends on thermal conductivity.

Convection

Transfer of heat by the movement of fluids (air or liquid) carrying energy.

Radiation

Transfer of heat by electromagnetic waves; can occur through a vacuum.

Insulation

Materials that resist heat transfer; reduce conduction, convection, and radiation.

Hydrometer

An instrument used to measure the density (or relative density) of liquids.

Crystalline solid

A solid with a well-ordered, repeating lattice structure.

Amorphous solid

A solid lacking a long-range ordered structure; molecules may be arranged irregularly.

Liquid

A substance with a definite volume but no fixed shape; expands when heated.

Gas

A substance with no fixed shape or volume; expands to fill its container.

Plasma

A highly ionized gas of charged particles; found in stars and the ionosphere.

Kinetic theory of gases

Gas consists of fast-moving molecules that collide; higher temperature means higher speeds; pressure arises from molecule-wall collisions.

Gravitational constant (G)

G = 6.67×10^-11 N·m^2/kg^2; universal constant in F = G m1 m2 / r^2.

Newton’s Law of Gravitation

Every two masses attract each other with a force proportional to their masses and inversely proportional to the square of the distance between them.

First Law of Thermodynamics

Energy cannot be created or destroyed; heat added to a system changes internal energy and/or does work.

Second Law of Thermodynamics

Heat does not flow spontaneously from cold to hot; entropy tends to increase.

Third Law of Thermodynamics

Absolute zero cannot be reached; virtually no molecular motion.

Work

The product of force and the distance moved in the direction of the force; W = Fd; measured in joules.

Energy

The ability to do work; exists in various forms (kinetic, potential, thermal, chemical, electrical, radiant, nuclear).

Kinetic energy

Energy of motion; KE = 1/2 mv^2.

Potential energy

Energy stored due to position; gravitational potential energy Ep = mgh.

Gravitational potential energy

Potential energy due to height in a gravitational field; Ep = mgh.

Power

Rate of doing work; SI unit is the watt (W); 1 W = 1 J/s.

Momentum

Mass times velocity (p = mv); conserved in isolated systems.

Torque

A turning force; τ = r × F; depends on lever arm length.

Angular momentum

L = Iω; conserved when no external torque acts.

Newton’s First Law

An object at rest stays at rest or in uniform motion unless acted on by a net external force.

Newton’s Second Law

Acceleration is proportional to net force and inversely proportional to mass (F = ma).

Newton’s Third Law

For every action, there is an equal and opposite reaction.

Fossil fuels

Oil, natural gas, and coal—energy sources derived from ancient organisms.

Renewable energy

Energy sources that are naturally replenished and not depleted with use.

Hydropower

Energy derived from moving water, typically via dams, converting potential to kinetic energy.

Wind power

Energy produced from wind using turbines; requires steady winds and has environmental considerations.

Solar power

Energy obtained from the sun, used in photovoltaic and thermal systems.

Geothermal energy

Heat energy derived from the Earth’s interior; site-dependent.

Tidal energy

Energy from tidal currents; reliable when using controlled tidal flow.

Biofuel energy

Fuel produced from biological materials (e.g., ethanol from plants).

Biomass energy

Energy from organic matter; renewable when sourced sustainably.

Displacement

The straight-line distance from an object's initial to final position, with direction.

Distance

The total length of the path traveled by an object.

Speed

A scalar quantity representing how fast an object is moving (magnitude only).

Velocity

A vector quantity describing speed with direction (magnitude and direction).

Acceleration

The rate of change of velocity; a = Δv/Δt; units m/s^2.