School Improvement in Maryland

Science State Curriculum Glossary


Nonliving features of an ecosystem such as climate, light, soil chemistry, and water availability.

Abyssal plain:

Flat areas on the ocean floor formed by the deposition of sediment.


The change that occurs in an object's speed or direction in a certain period of time.


A substance that donates hydrogen ions. Any compound that produces hydrogen ions (H+) in water thereby reducing the pH of water to a value below 7.


A characteristic, arising from natural selection, that that improves a population's chance of survival and reproduction.


The distance from the midpoint to the maximum point (crest) or to the minimum point (trough) of a wave. The distance that a wave rises and falls from its normal rest position.


An instrument used to measure wind speed.

Angle of Incidence:

The angle between the normal (perpendicular drawn to surface) and the incident ray.

Angle of Reflection:

The angle between the normal (perpendicular drawn to the surface) and the reflected ray.


Appearing real or true based on evidence that may not be valid.

Asexual reproduction:

Mode of reproduction in which offspring arise from a single parent and inherit the genes of that parent only.


Enormous rocks or boulders that revolve around the sun, usually between the orbits of Mars and Jupiter.


The layers of gases that surround Earth or another planet.


The smallest part of a substance which can exist and still retain the properties of that substance.

Atomic number:

Number of protons in the nucleus of one atom of an element.


Tool, calibrated in grams, used to measure the mass of an object.


An instrument that measures air pressure.


A substance that accepts hydrogen ions. Any compound that produces hydroxide ions (OH-) in water thereby raising the pH of water to a value above 7.

Behavior (animal):

A response to external and internal stimuli.


A large, relatively distinct terrestrial region, encompassing many interacting ecosystems, and characterized by similar climate, soil, plants, and animals, regardless of where it occurs on Earth. A biome is commonly named for its plant cover.


Features of the environment of an organism arising from the activities of other living organisms, as distinct from abiotic factors.

Boiling point:

The temperature at which a substance in its liquid state changes into a gas state.


A deep, narrow valley with steep sides.


A fossil formed in a rock showing the organism's outward shape. It formed after the organism dissolved and the space in the rock was filled.


Pertaining to the sky or visible bodies in the sky.


The smallest unit of life capable of carrying on life's functions.

Cell respiration:

A process by which energy stored in molecules is released within plant and animal cells.


A temperature scale in which the freezing point of water is 0° and the boiling point of water is 100°.


Process by which sedimentary rock is formed from sediments being glued together by mineral deposits.

Chemical change:

A change that results in the formation of a new substance, such as the burning of wood.

Chemical energy:

Energy stored in the chemical bonds of molecules.

Chemical properties:

Properties which cause specific behavior of substances during chemical reactions, such as reacts with oxygen, reacts with acids, reacts with bases.

Chemical reaction:

Change that takes place when two or more substances (reactants) interact to form new substances (products).


Process of separating small amounts of substances from mixtures by the rates at which they move through or along a medium.

Classification system:

A structured organizer used to determine groups based on similar characteristics.


Property of a mineral in which it breaks along smooth, definite surfaces.


The average temperature and rainfall for a particular place over hundreds of years.


Small frozen masses of ice, dust, and gases that travel a definite path through the solar system.


An association of different species living together at the same time in a defined habitat with some degree of mutual dependence. It can be of various sizes from lake sediments to rainforests (Compare with habitat and ecosystem).


Process by which sedimentary rock is formed when layers of sediment are compressed by the weight of layers above them.


The result of a common demand by two or more organisms or types of organisms for limited resources.


The chemical make up of a given substance.


A substance in which the atoms of different elements are bonded to one another. It can be broken down into simpler parts only by a chemical change.


1. The end of a reasoning process involving data, evidence, or observations from an investigation.
2. The closing paragraph of a laboratory report including at least the investigative question, the hypothesis, and the explanation of the results.


Process in which matter changes from a gaseous state to a liquid state.


Allow energy to flow through a material.


The transfer of heat energy through a substance or from one substance to another by direct contact of atoms or molecules.


A material through which electric current can flow easily.


Organism that eats other organisms for food.


A factor in an investigation that is kept the same; the standard used for comparison.


A method of transferring heat energy by the movement of the heated substance itself.

Convection current:

A circular current in a fluid like air, water, or molten rock. The process occurs when the fluid is unevenly heated so that part of the fluid rises, cools, and then sinks producing the circular movement.


The center of Earth or other celestial body.


The thin rocky outer layer of the Earth (also known as Earth's surface).

Crustal plate:

Any of the huge moving segments of the Earth's crust which travel over the Earth's mantle.


A solid with a definite shape, formed from a repeating pattern of atoms.


Collected information which can be quantitative (numerical) or qualitative (descriptive). Factual information used as a basis for reasoning, discussion, or calculation.


An organism that obtains energy from decaying organic material. (See Food chain, Food web, Consumer).


The amount of material an object has in a specific amount of space.

Dependent variable:

Factor whose value depends on the change the experimenter makes to the independent variable. It is the effect resulting from the scientific investigation. This quantity is plotted along the y-axis of a graph.


Process by which sediments are deposited in a new location.


A condition of the body in which there is incorrect function due to heredity, infection, diet, or environment.


One substance or object moving another substance or object, or taking its place.

Diversity of species:

The number of different species present in an area.


The ability of a substance to be stretched.


The moving and shaking of part of Earth's crust.


A group/community of organisms interacting with their environment.

El Nino:

A variation in worldwide weather patterns that recurs every three to five years and that is caused by changes in the wind, conditions over the Eastern Pacific Oceans.

Electric circuit:

Continuous path that can be followed by charged particles.

Electric current:

The flow of charged particles from one place to another.

Electrical conductivity:

A property of a mineral to transmit electricity.

Electrical energy:

Energy of electrical charges as a result of their position or motion.


A general term for the physical phenomena that arises from the interaction of electric charges.


The negatively charged particle that moves around the nucleus of an atom.


A substance that consists of only one kind of atom and cannot be broken down into simpler parts during a chemical reaction.


The ability to cause matter to move or change.

Energy transformation:

When energy changes from one type to another.


The physical surroundings of an organism which includes the living and nonliving components.


The carrying away of weathered soil, rock, and other materials on the Earth's surface by gravity, water, and wind.


A coastal body of water that connects to the oceans so that fresh water from a river mixes with saltwater from the oceans, such as in the Chesapeake Bay.


Change of matter from a liquid state to a gaseous state at a temperature below its boiling point.


Changes in species as a consequence of processes such as mutation and natural selection.


When most substances are heated their molecules move faster and further apart causing them to increase.


The elimination of a species (also applicable to levels other than species) due to natural processes or human activity.


The process of movement along a break or crack in Earth's crust.


Process of separating a liquid and a solid by pouring the mixture through a fine mesh.


An overflowing of a body of water onto normally dry land.


A property of a mineral to glow with certain colors when exposed to an ultraviolet light.


The process of bending rock layers in Earth's crust.


Scientific: substances that provide carbohydrates, lipids, and proteins as an energy source to organisms.

Food chain:

The feeding relationships of species that transfer energy through the organisms in a community.

Food web:

The complex interconnection of food chains in an ecosystem. (Compare Food chain)


A push or a pull applied to an object.


The remains or imprint of a prehistoric plant or animal.


The property of a mineral in which it breaks along rough, jagged surfaces.


The division of habitats that formerly occupied large, continuous areas into smaller areas by roads, fields, housing developments, and other human activities.


The number of repetitions in a given interval of time.


The force that acts between materials that touch as they move past each other. Friction is caused by irregularities in the surface of objects that are touching.


A boundary between air masses that have different temperatures and humidity. It is usually the site of unsettled weather conditions.


A large collection of stars, gas, and dust held together by mutual gravitation.


The state in which a substance has no definite shape or volume.


Of or relating to Earth or Earth processes.


A large mass of snow and ice moving along Earth's surface.


The mutual force of attraction between particles of matter. The magnitude depends on the masses of the particle and the distance between them.


The force of gravitational attraction on or near the surface of a celestial body.

Greenhouse gases:

Gases that are in the atmosphere that trap heat energy so that it can not escape to space.


Water that is in the porous parts of Earth's crust.


The local environment in which a specified organism, population, or species lives, characterized by physical and chemical features, and the presence of certain other species. (Compare ecosystem, biome, environment).


Property of a mineral's resistance to being scratched.

Heat Energy:

The energy of a material due to the random motion of its particles. Also called thermal energy. The word "heat" is used when energy is transferred from one substance to another.


An organism that supports a parasite either in or on its own body and to its own detriment.


A large, powerful cyclonic storm that forms over a tropical ocean.


Any part of the Earth or its atmosphere in which water or water vapor is found.


Plural of hypothesis. A hypothesis a prediction that can be tested and is based on an observation, experience, or a scientific reason The statement includes the expected cause and effect in a given circumstance or situation.

Igneous rock:

Rock formed through the process of magma or lava cooling and hardening.


The optical counterpart of an object formed by a mirror or a lens.


A fossil that is an organism's impression which was formed in mud that later hardened into rock.

Independent variable:

The factor/value altered by the experimenter during the scientific investigation. The changes made affect the value of the dependent variable. This quantity is plotted along the x-axis of a graph.

Index fossil:

A fossil of an organism that lived a relatively short time on Earth, used to determine the relative age of rock layers.


A substance that changes color when it comes in contact with an acid or a base.


The reluctance of any object to change its state of motion. Mass is the measure of inertia.


To receive a characteristic (genes) from an ancestor.


A trait that is inborn- genetically inherited.


(1) A material that is a poor conductor of heat energy.
(2) A material that is a poor conductor of electricity.


The relationships between or among organisms necessary for their survival.


To observe or study by using a systematic inquiry approach.

Kinetic energy:

Energy of motion.


A position relative to the distance North or South from the Earth's equator, measured in degrees.

Law of Conservation of Energy:

Energy cannot be created or destroyed- only changed from one form to another.

Law of Conservation of Mass:

Mass can be neither created nor destroyed during a chemical reaction- only changed from one form to another.

Law of Electrostatics:

Law that states like charges repel; unlike charges attract.

Law of Superposition:

Law that states in undisturbed sedimentary rock layers, the younger layer is closer to Earth's surface and the older layer is below this.


Electromagnetic radiation or electromagnetic waves which are visible to the human eye.


The state in which a substance flows and takes up the shape of its container.

Litmus paper:

An indicator which shows whether a solution is acidic or basic (acids turn blue litmus paper red; bases turn red litmus paper blue).

Longitudinal wave:

A wave in which the vibration is moving in the same direction as that in which the wave is traveling.


Ability to reflect light.


Having the properties of a magnet.

Magnetic field:

A region of space around a magnet in which objects are affected by the magnetic force.


The field of force produced by a magnet or an electric current.


The apparent enlargement of an object by an optical instrument.


Ability of a substance to be molded into different shapes.


The middle layer of the Earth between the crust and the core.


A measure of the amount of matter in an object.

Mass number:

The number of protons and neutrons in the nucleus of an atom.


Anything that has volume and mass.

Mechanical Energy:

Energy an object has because of its motion or position.


Elements that usually have luster, conduct heat energy and electricity, and usually bend without breaking.

Metamorphic (rock):

Rock formed when igneous or sedimentary rock is changed by pressure, heat, or chemical reactions.


A meteoroid that burns as it travels through Earth's atmosphere leaving a streak of light made of hot gases.


A naturally occurring, nonliving solid with a characteristic crystal, structure and definite chemical makeup.


A combination of two or more substances that have not combined chemically and that can be separated by physical means.


An illustration, description, small reproduction, or other, representation that is used to explain an object, system, or concept.


A fossil that is an empty space in a rock that shows the outward shape of a dissolved organism.


The smallest unit of a substance that has all of the physical and chemical properties of the substance and that is composed of two or more atoms.


The product of the mass times the velocity of an object.


A natural satellite revolving around a planet.


Change in position of an object relative to a reference point.


A landform with a high elevation.

Mud flow:

A downhill movement of mud which usually occurs after a heavy rainfall.


Composed of more than one cell.

Natural resource:

Something from the natural environment (water, air, trees, fuels) that is used to meet one's needs and wants.

Neap tide:

A tide that occurs during the first and last quarter phases of the moon in which the water level is lower than normal.


A substance that does not have the properties of an acid or a base, but has an equal number of hydrogen and hydroxide ions. It has a pH of 7.

Neutral atom:

An atom with an equal number of protons and electrons is electrically neutral.


Particle with a neutral charge located in the nucleus of an atom.

Newton's Laws of Motion:

Three laws that explain the relationships between force and motion.

Nitrogen (cycle):

The global circulation of nitrogen brought about mainly by living things.

Noble gases:

Group of elements in the periodic table that generally do not react with other elements, such as neon and krypton.


1. A material through which an electric current does not flow.
2. A material through which heat energy does not flow.


Elements that in general do not conduct electricity, are poor conductors of heat, and are brittle when solid.

Nonnative species:

Plants and animals that are not native to an environment, introduced intentionally or accidentally. When these plants or animals outcompete and crowd out native species for space, light, and nutrients, they are considered to be invasive.

Nonrenewable resource:

Resources that can be depleted, such as coal, oil, and minerals.

Nuclear energy:

Energy that is released either by splitting atomic nuclei or by forcing the nuclei of atoms together.


To gather information and direct evidence by using senses and/or scientific instruments.


The continuous body of salt water on Earth.

Ocean current:

A tidal or non-tidal continuous movement of ocean water in a certain direction.


The product of reproduction by an organism or organisms.

Optical activity:

A property of certain minerals to reflect or refract light, such as Iceland spar bends light in two directions showing a double image.


A path of one body in its revolution about another body.


A structure made up of different types of tissues that work together to do a specific job.


A living thing.

Parallel circuit:

Electrical circuit arranged so that current passes through more than one pathway simultaneously.


A symbiotic relationship between two organisms in which one (the parasite) benefits to the detriment of the other (host).


An agent (usually a microorganism) that causes a disease.


Repeated sequences of natural occurrences. A configuration of shapes or other objects arranged in such a way as to demonstrate a specific repeat in design.

Periodic table:

A chart where all elements are organized into periods and groups according to their properties.


Fossilized remains that have been turned into stone.

pH scale:

Scale ranging from 0-14, used to describe how acidic (0) or basic (14) a substance is. The pH is the measure of the hydrogen ion concentration in a solution.

Phases (lunar):

The regularly occurring cycle of changes in the appearance of the moon.


The process by which green plants use water and carbon dioxide and light from the sun to make food.

Physical change:

A change that occurs in the physical property/properties of a substance without altering its composition.

Physical properties:

Any property of matter that can be observed by your senses.


How high or low sound frequencies appear to be.


A major body (not a comet or asteroid) orbiting around a star.

Plate tectonics:

Large crustal plates moving on the Earth's surface and resulting in changes in the Earth's surface.


Human and natural contamination of the environment by chemicals or heat energy to the extent that existing habitats are threatened or populations of organisms are endangered.


A group of organisms of the same species that live in the same area at the same time.

Potential energy:

The stored energy of a body because of its position.


Process by which water falls to Earth from the atmosphere in the form of rain, snow, sleet, or hail.


An organism that kills and consumes another organism (prey); includes animals eating other animals, and animals eating plants.


A broad statement (based on an observation, experience, or scientific reason) of what will happen (the effect) in a given circumstance or situation.


An organism that is killed and eaten by another organism.


An organism that makes its own food.


Positively charged particles in the nucleus of an atom.


An instrument used to measure relative humidity.


Data that is related to the quality of observations.


Energy traveling through empty space or through a transparent material without heating the empty space or transparent material.


Compound or element that changes during a chemical reaction.


Ability of an element to gain or lose electrons which are used for bonding.


The change in velocity and apparent bending of the beam of light or other wave-form as it passes from one medium into another.

Relative age:

The age of a rock (older or younger) in comparison with the age of other rocks.

Renewable resource:

Resources that can be replenished, such as trees and plants.


The movement of a celestial body in an orbit around another celestial body.


A natural stream of water with a large volume.

Rock slide:

A mass of rock sliding down a hill or mountainside.


The spinning motion of a planet or other object on its axis.


The concentration of dissolved salts (usually sodium chloride) in a body of water.

Sand dune:

A mound of sand that is deposited by the wind.


An object that moves around Earth or some other object rather than falling onto it.


An organism that feeds on dead organic matter.

Sea floor spreading:

Process by which new ocean floor is formed by lava erupting from a rift valley, pushing the existent floor outward from the rift.


Changes in temperature and the length of day and night over the course of a year.


Small pieces of rock, shell, and plant and animal matter that is moved and deposited by water, wind, or ice.

Sedimentary rock:

Rock formed from sedimentation.


The settling out of fragments of weathered rock or remains of living things that are carried and deposited by wind, water, or ice.

Selective breeding:

Selection for specific traits imposed by humans, either deliberately or otherwise, upon wild or domesticated plants and animals.

Series circuit:

An electric circuit in which the current passes through only one pathway.

Sexual reproduction:

Mode of reproduction involving two parents, usually involving meiosis, gamete formation, and fertilization.

Solar energy:

Energy from the Sun in the form of light and heat energy.

Solar System:

The Sun with the group of celestial bodies that revolve around it.


The state in which a substance has a definite volume and shape and resists forces which try to change these.


Ability of a substance to dissolve in another substance.


Mixture in which the molecules of one substance (solute) are dissolved in another substance (solvent).


Longitudinal wave produced by the vibration of a material.


Organisms whose members are alike and successfully reproduce among themselves.


A scalar quantity that describes the change in position in a certain period of time (how fast something is moving). (Compare with velocity.)

Spring scale:

Tool that is calibrated in Newton's and is used to measure the weight of an object.

Spring tide:

Tide that occurs during the full and new moon phases in which the water level is higher than normal.

Standard unit:

Inches, feet, yard, centimeters, meters, grams, ounces, pounds, Celsius degrees, Fahrenheit degrees, hours and minutes and non-standard units (i.e. paper clips).


A natural, luminous, celestial body.

State of matter:

The forms matter can take, as in liquid, solid, or gas.

Static electric charge:

Potential energy in the form of a stationary electric charge.


The color of the powder that a mineral leaves when it is rubbed on a hard, rough surface.


Matter of a particular kind, or chemical makeup.


The star around which Earth and the other planets revolve that provides the main source of energy for living things on Earth.

Symbolic equation:

Represents the relationship between two or more physical quantities expressed as symbols which represent the quantities.


A group of organs that work together to perform a specific job.


The measure of the average energy of motion of the particles of a substance.


A storm with heavy rainfall, lightning, and thunder produced by cumulonimbus clouds formed when a cold front collides with a warm front.


The alternate rising and falling of the surface of the ocean and of water bodies connected with the ocean. It occurs twice a day and is caused by the gravitational attraction of the moon and the sun occurring unequally on different parts of the Earth.


The angle between the Earth's axis and the line perpendicular to the plane of the Earth's orbit.


Rock layers that move or shift at a slanted angle.


A group of similar cells working together to perform a specific job.


A destructive, whirling, funnel-shaped cloud that has extremely low air pressure.


Harmful (adjective). (Compare with toxin - a harmful chemical produced by living things).


A characteristic which is passed on to offspring through heredity.

Transverse wave:

A wave in which the vibration is moving in a direction perpendicular as that in which the wave is traveling.


The general drift, tendency, or direction of a set of data.


Large sea wave produced by submarine earth movement or volcanic eruption.


Organisms composed of one cell only.


The raising of an area of land due to horizontal forces that slowly push on the area.


A depression on Earth's surface between ranges of hills or mountains.


Any factor in an investigation that could affect the results.


The rate of motion, or speed, in a specified direction.


The back and forth motion of an object.

Volcanic eruption:

Process by which lava reaches Earth's surface.


Amount of space an object or substance takes up; measured in liters or cubic centimeters.

Water cycle:

The process, involving evaporation and condensation, by which the Earth's water circulates through the environment.


The distance between two identical points on neighboring waves.


The short-term conditions of the atmosphere determined by variables such as temperature, wind, moisture, and pressure.


A chemical or physical process in which rocks exposed to the weather are worn down by water, wind, or ice.


The measure of the gravitational force acting on an object.

Well-designed investigation:

A detailed inquiry or systematic examination which includes the following criteria:
• only one variable is tested
• testing conditions such as time, temperature, and surfaces are controlled
• multiple trials are completed
• appropriate materials and equipment are selected
• clear, logical directions are included

White light:

All the colors of the spectrum visible to the human eye as a single color.

Word equation:

Represents the relationship between two or more physical quantities expressed as words.


The product of the force on an object and the distance through which the object is moved.