FCAT Science Glossary Grade 8
(Knowledge of the terms in the Grade 5 glossary is assumed.)
abiotic an environmental factor not associated with the activities of living organisms
acceleration rate of change in velocity, usually expressed in meters per second; involves an increase or decrease in speed and/or a change in direction
air resistance force of air on moving objects
allele any of two or more alternate forms of a gene that an organism may have for a particular trait
amplitude in any periodic function (e.g., a wave) the maximum absolute variation of the function
asexual reproduction a form of reproduction in which new individuals are formed without the involvement of gametes
biodiversity the existence of a wide range of different species in a given area or specific period of time
biotic factors in an environment relating to, caused by, or produced by living organisms
calorie unit of energy; the amount of heat needed to raise one gram of water one degree Celsius at standard atmospheric pressure
chemical weathering the breakdown and alteration of rocks at or near Earth’s surface as a result of chemical processes
circuit an interconnection of electrical elements forming a complete path for the flow of current
conduction the transmission of heat through a medium and without the motion of the medium
conservation of energy a fundamental principle stating energy cannot be created nor destroyed but only changed from one form to another
convection heat transfer in a gas or liquid by the circulation of currents from one region to another
crest the peak or highest point on a wave
crust outermost layer of Earth covering the mantle
dependent variable factor being measured or observed in an experiment
deposition the process by which sediment is carried by forces (e.g., wind, rain, or water currents) and left in a certain area
diffraction the change in direction of a wave caused by passing by an obstacle or traveling through an opening
dominance tendency of certain (dominant) alleles to mask the expression of their corresponding (recessive) alleles
ecosystem an ecological community, together with its environment, functioning as a unit
efficiency the relative effectiveness of a system or device determined by comparing input and output
electromagnetic radiation the emission and propagation of the entire range of electromagnetic spectrum including: gamma rays, x-rays, ultraviolet radiation, visible light, microwaves, and radio waves
electron a stable elementary particle that is negatively charged and orbits the nucleus of an atom
entropy a measure of randomness or disorder of a closed system
erosion a combination of natural processes in which materials from Earth’s surface are loosened, dissolved, or worn away and transported from one place to another
fossil fuels the remains of animal or plant life from past geologic ages that are now in a form suitable for use as a fuel (e.g., oil, coal, or natural gas)
frequency the number of cycles or waves per unit time
gene a specific part of a chromosome or sequence of DNA that determines a particular feature or characteristic in an organism
heterozygous cell or organism that has two different alleles for a particular trait
homozygous cell or organism that has identical rather than different alleles for a particular trait
independent variable the factor that is changed in an experiment in order to study changes in the dependent variable
inertia the property of an object, due to its mass, by which it resists any change in its position unless overcome by force
magnetic field the region where magnetic force exists around magnets or electric currents
mass the amount of matter an object contains
meiosis the process of nuclear division in cells during which the number of chromosomes is reduced by half
mitosis a process of nuclear division in eukaryotic cells during which the nucleus of a cell divides into two nuclei, each with the same number of chromosomes
neap tide a twice-monthly tide of minimal range that occurs when the Sun, Moon, and Earth are at right angles to each other, thus decreasing the total tidal force exerted on Earth
neutral a particle, object, or system that lacks a net charge
neutron a subatomic particle having zero charge, found in the nucleus of an atom
nucleus the center region of an atom where protons and neutrons are located; also a cell structure that contains the cell’s genetic material
ocean basin a depression on the surface of Earth occupied by water plate tectonics theory of global dynamics in which Earth’s crust is divided into a smaller number of large, rigid plates whose movements cause seismic activity along their borders
potential energy energy stored in an object due to the object’s configuration and position
pressure the force exerted per unit area
prism a piece of glass with polished plane surfaces that disperses a beam of white light into its component colors
proton a subatomic particle having a positive charge and which is found in the nucleus of an atom
Punnett square a graphic checkboard used to determine results from a particular genetic cross
radiation emission of energy in the form of rays or waves
recessive an allele for a trait that will be masked unless the organism is homozygous for this trait
screw a type of simple machine that consists of an inclined plane wrapped around a cylinder
sexual reproduction reproduction involving the union of gametes producing an offspring with traits from both parents
spectroscope an instrument that uses a prism to separate and catalog light wavelengths
speed amount of distance traveled divided by time taken; the time-rate at which any physical process takes place
spring tide the tide of increased range that occurs twice monthly at the new and full phases of the Moon
thermal energy internal energy found by adding the kinetic energy of particles making up a substance
tropism the motion of an organism or part of an organism toward or away from an external stimulus
trough the lowest point on a wave
variable an event, condition, or factor that can be changed or controlled in order to study or test a hypothesis in a scientific experiment
velocity defined as the time-rate at which a body changes its position
displacement divided by the time of travel
vibration a repetitive movement around an equilibrium point
virus a noncellular, disease-causing particle that uses the genetic material from its host to reproduce
wavelength the distance between crests of a wave
wedge a type of simple machine that consists of an inclined plane used to separate two objects
wheel and axle a type of simple machine that consists of a rod driven through the center of a cylinder that is allowed to rotate freely, yielding a mechanical advantage equal to the cylinder’s diameter