Applied Physical Science Glossary absolute pressure The total of gauge pressure plus atmospheric pressure. acceleration The rate at which a moving body changes velocity. alternating current The flow of electrons alternately pulled in one direction and then the opposite direction. atmospheric pressure The pressure exerted by the air around you which is approximately 14.7 psi. balanced force Occurs when equal but opposite forces are exerted on an object resulting in no motion. Bernoulli’s Principle States that when velocity of a flow increases, pressure decreases. buoyancy The force that pushes an object up in a fluid. centrifugal force The force that pushes a body away from the center of a circular path. centripetal force The net force that makes a body follow a curve (or move toward a central point). chemical energy Potential energy stored in the bonds that hold the atoms together in a molecule. circuit breaker A switch designed to detect an electrical fault and automatically trip or open a circuit. conduction The transfer of heat through matter from particle to particle. convection The transfer of heat by the actual movement of the warmed matter. current The rate of flow of an electrical charge. density The measure of the mass of matter compared to its volume. direct current The flow of an electrical charge in a single direction through a conductive material. drag The force which acts on a body as it moves through a gas or liquid. efficiency The comparison of useful energy output to the useful energy input. electrical conductor A material across which electric current can flow freely. electrical insulator A material across which electric current does not flow freely. Good insulators are characterized by their high resistivity. electricity The flow of electrons from one atom to another. electromagnetic energy The energy of moving electrical charges. electromagnetic force The force is caused by the interaction between positively charged protons and negatively charged electrons. enthalpy The total energy from any medium in its current state. force A push or pull that causes a body to accelerate or change directions. Mathematically: Force = Mass x Accelleration. friction The force between two surfaces that is dependent upon the roughness or characteristics of the surfaces and the weight, but not the surface area. fulcrum The fixed pivot point of a lever. fuse An electrical safety device designed to open, or break, a circuit if the current exceeds a safe level. gauge pressure The reading from a pressure gauge that is calibrated to 'zero' at the standard atmospheric pressure for a given location. The absolute pressure minus the atmospheric pressure. gravitational energy The potential energy of place or position due to gravitational pull. gravity The force that pulls a body toward the center of the earth. heat The transfer of thermal energy from one source to another. Hooke’s Law States that the force developed by a stretched or compressed spring is proportional to the distance it is stretched or compressed. Mathematically: F = -kx, where F is force, x is the distance the spring is stretched or compressed and k is the spring constant. inertia The tendency of a body to remain at rest or stay in motion unless acted upon by an external force. kinetic energy Energy in motion. laminar flow A fluid flow that is smooth and uniform. latent heat Heat that causes a phase change (without a temperature change). latent heat of fusion Energy required to change a substance from a solid to a liquid. latent heat of vaporization Energy required to change a substance from a liquid to a gas. Law of Conservation of Energy States that energy can neither be created nor destroyed. lever A rigid object that can move freely around a fixed point (fulcrum). machine A device that changes the amount of force exerted or the direction of a force. magnetic field The energized space that surrounds a magnet or electric current. mechanical advantage The ratio of output force to input force. mechanical energy The energy associated with the motion or position of an object. normal force The force that supports an object in contact with another object. nuclear energy The potential energy stored in the nucleus of an atom. Pascal’s Principle States that a change in pressure of an enclosed uncompressible fluid is conveyed undiminished to every part of the fluid. potential energy Stored energy or energy of position. power The measure of the amount of energy per unit of time. pressure Force per unit of area. radiant energy Electromagnetic energy that travels in waves which possess both electrical and magnetic properties. radiation A form of energy transport consisting of electromagnetic waves. resistance A measure of a material or circuits opposition to the flow of electricity. sensible heat Heat that causes a temperature change and can be measured by the thermometer. simple machine A device that only requires the application of a single force to perform work. solenoid A coil of wire that produces a magnetic field when an electric current passes over it. One application of a solenoid is to 'trip' a circuit breaker. specific gravity The ratio of the density of a substance to the density of a reference substance. specific heat The amount of energy required to raise 1 gram of a substance 1 degree Celsius or 1 pound of a substance 1 degree Fahrenheit. spring constant A function of the type of material the spring is made of, the diameter of the wire it made from, the radius of the coils, and the number of coils it contains. spring force The force that acts on a spring to return it to its natural length. Mathematically: F = -kx, where F is force, x is the distance the spring is stretched or compressed and k is the spring constant. static electricity The build up of negatively charged electrons on a surface. temperature The meas