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a nonliving physical and chemical attribute of a system; e.g. light, temperature, wind patterns, rocks, soil, pH, pressure, etc. in an environment


the basic structural, functional, and biological unit of all organisms

electrical energy

this results from the change in motion or position of electrical charges


molecules that are only weakly attracted to each other and are free to move about in space


having protection (antibodies) against disease -causing agenets


the process that occurs in sex cells (sperm and egg) in which the number of chromosomes is reduced by half


curved path followed by a planet, moon, or satellite as it revolves around an object


involving quality or kind, recorded with a characteristic that cannot be expressed in numbers


the time it takes for a planet to complete one revolution around a star

sex cell

reproductive cell


a well-tested explanation of some aspect of the natural world

balanced forces

equal force acting on an object in opposite directions, the object does not move


a small body composed of ice and rock that travels in an elliptical orbit around the sun

data table

a framework for organizing data measured or recorded from an experiment


change over time


a state in which metabolism slows in certain animals reducing their need for food and protecting them from cold

luar eclipse

event in which the shadow of Earth falls on the moon


the unit for force (symbol N)

plate boundries

the edges where two or more tectonic plates meet; may be convertgent, divergent, or transform


periodic rise and fall of water level due to gravitational attraction of the sun and the moon acting on Earth

Ring of Fire

an area associated with plate boundaries around the Pacific Ocean that has a large amount of volcanic and earthquake activity

spontaneous generation

theory that life began from nonliving matter


1. a straight line about which a body or a geometric figure may rotate 2. a straight line with respect to which a body or figure is symmetrical


process of a gas changing to a liquid, such as water vapor into water droplets


when sediments are carried by wind or water and are deposited in a new location

food web

all of the interactive feeding relationships by which energy and nutrients are transferred between organisms in a community

igneous rock

forms as molten rock cools and becomes solid


anything that has mass and takes up space

moon phases

the change in the sunlit area of one celestical body (the moon) when viewe from another celestial body (Earth)


any organism such as a plant or protist that is able to make food through photosynthesis or chemosynthesis


a simple machine consisting of an inclined plane wrapped around a central bar


average kinetic energy (movement) of molecules in an object

apparent brightness

measure of a star's light observed or received at a certain position (apparent magnitude)

boiling point

temperature at which a liquid becomes a gas


an organism that eats dead or decaying matter

energy transformation

process of changing one form of energy to another

global warming

the gradual increase of the temperature of Earth's lower atmosphere as a result of the increase in greenhouse gases


the solid, outer layer of the Earth that consists of the crust and the rigid upper part of the mantle

net force

the combination of all forces acting on an object


group of organisms of the same species living and reproducing in a particular geographic region


simple machine that is thick at one edge and tapered to a thin edge at the other for insertion in a narrow crevice

sample size

number of individuals in the experimental and control groups


an object that has mass and occupies space

air resistance

friction experienced by objects moving through air

chemical property

property that changes the chemical nature of matter when in the presence of other substances or conditions; e.g. heat of combustion, ractivity with water, pH, electromotive force

digestive system

body organs responsible for getting food into and out of the body and for making use of food

greenhouse gas

gas such as carbon dioxide or methane which contribues to potential climate change


moist air mass originating over water


an organism that is active at night


energy transfer without direct contact, as in the transport of heat from the sun to Earth


electromagnetic waves with frequencies higher than visible light, but lower than x-rays

respiratory system

the system by which oxygen gets taken into the body and an exchange of oxygen and carbon dioxide takes place


a celestial body made of hot gases in which nuclear fusion occurs and from which energy is radiated

atmospheric pressure

the weight of the atmosphere pressing on the surface of Earth


a green structure of plant cells and other organisms in which food is made by photosynthesis

dependant variable

the factor measured or observed to obtain results (sometimes referred to as the responding variable), usually graphed on the y-axis

enerygy pyramid

a graphical representaiton showing the flow of energy through an ecosystem


the resistance of an objec to a change in the speed or direction of its motion

media (medium)

an intervening substance, such as air, through which a force acts or an effect is produced


1. describes compounds containing the element carbon 2. coming from an organism 3. food from an animal or plant that has been raised without synthetic pesticides, fertilizers, etc.


the process in which pollen is transferred from the male to the female part of ht flower or cone


amount of space occupied by an object


the turning of an object on its central axis

survival of species

the theory that individuals in a population best able to obtain and use resources will survive and reproduce; i.e. survival of fittest


microscopic, single-celled organisms that possess a prokaryotic type of cell structure


sediments pressed together by gravity and their own weight


to change from a solid to a dispersed form in fluid

fossil fuels

fuel derived from ancient organic remains; e.g. peat, coal, crude oil, natural gas


a testable explanation for an observation or scientific problem


one of the measures of central tendancy (average); the sum of numbers in a set of data divided by the number of pieces of data

nuclear energy

1. the energy released by a fission or fusion reaction 2. the binding energy of the atomic nucleus


any form of water that falls from the clouds; e.g. rain, snow, hail, sleet


process by which materials change when exposed to conditions at or near Earth's surface

sexual reproduction

producing a new generation by the combining male and female sex cells

tectonic plates

extremely large pieces of lithosphere (Earth's crust)


the scientific study of objects and their properties outside Earth's atmosphere


a summation of what is learned from an experiment


a negatively charged subatomic particle that resides outside (but is bound to) the nucleus of an atom


facts or signs that help one to form an opinion based on observations


all wateell as on Earth; in the atmosphere as well as in oceans, lakes, glaciers, rivers, streams, and underground reservoirs

melting point

when heat is being added, the temperature at which a solid becomes a liquid

nonrenewable resource

a resource that forms at a rate that is much slower than the rate at which it is consumed; e.g. oil


substances which harm the environment; e.g. smoke, pesticides, litter

unbalanced force

a nonzero net force, which changes an object's motion

sediment load

the amount of sediments a stream can carry


a group of organisms that are capable of breeding to produce fertile offspring

average speed

the total distane divided by the total time


an ecological unit composed of groups of organisms or a population of different species occupying a particular area


when plate boundries move away from each other


fusion of gametes to produce a new organism of the same species


when things are not equal


a form of electromagnetic energy that travels in waves through space and can be seen when it interacts with matter

natural selection

1. the process by which individuals that are better adapted to their environment survive and reproduce more successfully than less well adapted individuals 2. a theory to explain the mechanism of evolution


any large natural, spherical object that revolves around a star


the force of gravity exerted on an object's mass


an action following a stimulus


substance with definite shape and volume, the atoms are packed tightly together in a regular pattern with little movement

biological diversity

the range of natural variety of species in an ecosystem

conservation of mass

the principle by which matter is neither created nor destroyed when it undergoes a chemical reaction


the material between the nuclear and cell memberanes; icludes fluid, organelles, and various membranes

acid rain

precipitation containing acids that forms in the atmosphere when industrial gas emissions (especially sulfur dioxide and nitrogen oxides) combine with water

circulatory system

this system consists of the heart and a closed system of vessels (arteries, veins, and capillaries) which provide a continuous flow of blood to your body, supplying the tissues with oxygen and nutrients


one of the known chemical substances that cannot be broken down further without changing its chemical properties


the genes that an organixm possesses for a particular trait-genotype is not just the expressed gene; instead, it includes any recessive genes masked by the dominant gene of a coded pair

kinetic energy

energy of motion


a quantity defined as the product of the mass and velocity of an object


chemical process in which a plant cell or protist uses energy from sunlight along with carbon dioxide and water to produce food (glucose) and oxygen


periodic changes in climate due to Earth's position relative to the sun


1. a group of related objects 2. a group of organs working together


a characteristic that helps an organism survive in its environment or reproduce

continental drift

the gradual movement of continents by tectonic plates under Earth's surface which causes land masses to move toward or away from one another


the interacting system of a biological community and its non-living environmental surroundings

food chain

a sequence of organisms within a community, each of which uses the next, lower member of the sequence as an energy source


the force of attraction between all masses in the universe


self-propelled movement


a measure of the amount of matter in an object


smallest particle of a substance that retains all the properties of the substance and is composed of one or more atoms


special quality or featrue of a substance or an organism that may be used for identification


a substance with an unstable atomic nucleus that loses energy by emitting particles or electromagnetic waves

spring scale

tool used to measure force or weight


having the affect of poison


the smallest particle of an element that can exist either alone or in combination


classification of certain physical and chemical characteristics of an environment, such as tundra, grassland, etc.


the part of the world in which life can exist

cell theory

theory that all known living things are made up of cells, the cell is the structural and functional unit of all living things, and all living cells come from pre-existing cells

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