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8th Grade Science EOG Vocabulary

The nonliving, physical features of the environment, including air, water, sunlight, soil, temperature, and climate.
Absolute Age
The actual age in years of an event or object; can be determined using radioactive dating or tree rings.
An inherited mutation in an organism's DNA that provided an advantage for survival of a species.
A group of medicines used to kill or slow the growth of bacteria that cause disease. Used to treat bacterial infection (only prescribed by doctors).

Taking too often or when unneeded can lead to antibiotic resistance.
An underground layer of rock that contains groundwater.
The smallest unit of an element that has all the properties of an element; it is the basic building block of matter.
Atomic Mass
The average mass of the atoms of an element (protons and neutrons). Typically found at the bottom of the element square (ex: Carbon has an atomic mass of 12.01).
Atomic Number
The number of protons found in the nucleus of an atom (ex: Nitrogen has an atomic number of 7). This number identifies the element.
An organism that can make its own food and most often does so by photosynthesis or chemosynthesis.
Single-celled organism that lacks a nucleus (prokaryote), some of which cause human disease.
Organisms that live on the bottom of the ocean or other body of water (starfish)
Organism or components of organisms that are used to assess the health of a water system (ex: trout)

Need a specific set of conditions to survive.
The study of the morality (what is good and bad) surrounding medical research and health care practices.
A type of fuel (most commonly used for transportation because they reduce the emission of greenhouse gases) that is derived from living or recently living matter.
The production of light by means of a chemical reaction in an organism.
Organic matter that can be used as a source of energy.
The use of living organisms to solve an engineering problem or perform an industrial task (ex: using bacteria that feed on hydrocarbons to clean up an oil spill).
Describes the living factors in the environment.
Boiling Point
Temperature at which a liquid changes to a gas.
Carbon Dating
Use to estimate the age of a fossil by analyzing the amount of Carbon-14 that is present.
Chemical Digestion
The process that breaks large molecules in food into smaller molecules.
Chemical Property
A characteristic of a pure substance that describes its ability to change into a different substance.
Chemical Reaction
The process in which substances undergo chemical changes that result in the formation of new substances.
The formation of food using energy released from chemical reactions instead of the sun.
The relation between two different kinds of organisms when one receives benefits from the other without damaging it. ( + 0 )
Two or more elements that are chemically combined.
The process by which a gas changes to a liquid.
The ability of an object to transfer heat or electricity to another object.
Continental Drift
The slow movement of the continents over Earth's surface caused by forces inside Earth.
Careful use of resources to reduce damage to the environment though such methods as composting and recycling materials.
A measure of how much mass is contained in a given volume.
Dissolved Oxygen
Measure of water quality indicating free oxygen dissolved in water. Inverse relationship with temperature.
A negatively charged particle that is found outside the nucleus of an atom.
Any substance that cannot be broken down into simpler substances.
A sudden and widespread outbreak of a disease within a specific population group or area
A coastal inlet or bay where fresh water from rivers mixes with salty ocean water (brackish water).
Many mammals and fish (aquatic life) prefer to nurse young in estuaries.
The process by which molecules at the surface of a liquid absorb enough energy to change to the gaseous state.
Evidence for a Chemical Reaction
1. Color change. 2. Solid (precipitate) forms. 3. Bubbles form. 4. Heat and/or flame is produced. 5. Heat is absorbed.
Describes a type of organism that no longer exists anywhere on Earth.
An igneous rock layer formed when lava flows onto Earth's surface and hardens
A break or crack in Earth's lithosphere along which the rocks move.
Food Chain
The pathway of energy transfer through various stages as a result of the feeding patterns of a series of organisms.

Arrows represent a flow of energy.
Food Web
A network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem.

Arrows represent a flow of energy.
The preserved remains or traces of living things.
Fossil Fuel
A nonrenewable energy resource formed from the remains of organisms that lived long ago; examples include oil, coal, and natural gas.
Freezing Point
The temperature at which a liquid changes into a solid.
A kingdom of complex organisms that obtain food by breaking down other substances in their surroundings and absorbing the nutrients (ex: molds, mushrooms, yeast).
Genetic Engineering
The science of altering and cloning genes to produce a new trait in an organism or to make a biological substance such as a protein or hormone.
Geologic Time Scale
The summary of Earth's history, divided into intervals of time defined by major events or changes on Earth.

Eon - era - period - epoch
Genetically Modified Organism - An organism whose genetic material has been altered using genetic engineering techniques. GMOs are used in biological and medical research, production of pharmaceutical drugs, experimental medicine (e.g. gene therapy), and agriculture (e.g. golden rice, resistance to herbicides).
Vertical columns #1-18 on the Periodic Table. Elements in each family are similar, they react similarly and they have similar characteristics because they have the same number of valence electrons.
The area where an organism lives, including the biotic and abiotic factors that affect it.
The length of time it takes for half of the atoms in a sample of a radioactive element to decay into atoms of another, stable element.
Heterogeneous Mixture
A mixture in which the parts are not evenly distributed.
An organism that cannot make its own food.
Homologous Structures
Anatomically similar structure inherited from a common ancestor.

Human arm; dolphin fin. We share a common ancestor and have similar anatomy, but TOTALLY different functions
Homogeneous Mixture
A mixture in which the parts are evenly distributed.
Host Cell
A living cell in which a virus can actively multiply or in which a virus can hide until activated by environmental stimuli.
Hydroelectric Power
Electricity produced using the energy of flowing water.
All water on Earth - including the atmosphere (water vapor), oceans, lakes, streams, rivers, glaciers, and underground reservoirs.
Ice Core
A tubular sample that shows the layers of snow and ice that have built up over the years, which is used to study Earth's past climate and events.
Igneous Rock
Rock that forms when molten rock/lava cools and hardens. Typically does not contain fossils because of the extreme temperatures.

Intrusive igneous (forms inside Earth due to magma cooling and hardening)

Extrusive igneous (forms on the surface due to lava cooling and hardening)
Index Fossil
A fossil of an organism that was common, lived in many areas, and existed only during a certain span of time. Used to help determine the age of rock layers.
Infectious Disease
An illness that can pass from one organism to another.
Intertidal Zone
An area that stretches from the highest high-tide line on land out to the point on the continental shelf exposed by the lowest low tide. Organisms in this region (crabs, limpets, and barnacles) are well-adapted to changes in water, temperature, and salinity, and can withstand the pounding of waves.
An igneous rock layer formed when magma hardens beneath Earth's surface.
Law of Conservation of Mass
The principle stating that mass/matter/energy is not created or destroyed during a chemical reaction.

If we start with a setup of 60 g, we should end with a total setup of 60 g even after the reaction has occurred.
Law of Superposition
The geologic principle that states that in horizontal layers of sedimentary rock, each layer is older than the layer above it and younger than the layer below it.
The visual property of something that shines with reflected light.
An infectious tropical disease caused by a protist (Plasmodium) and transmitted to humans by a mosquito; it produces high fevers, chills, sweating, and anemia.
A term used to describe material that can be pounded into shapes.
Anything that has mass and occupies space.
Melting Point
The temperature at which a substance changes from a solid to a liquid; the same as the freezing point, or temperature at which a liquid changes to a solid.
A class of elements characterized by physical properties that include shininess, malleability, ductility, and conductivity; found to the left of the stair step line on the Periodic Table.
An element that has some characteristics of both metals and nonmetals; typically found along the stair step line of the Periodic Table.
Two or more substances that are mixed together but not chemically combined.
A type of symbiosis in which both partners benefit from living together. ( + + )
Natural Selection
Process by which individuals that are better suited to their environment survive and reproduce most successfully; also called survival of the fittest.
Free-swimming animals that can move throughout the water column.
Neritic Zone
The area of the ocean that extends from the low-tide line out to the edge of the continental shelf.
A small particle in the nucleus of the atom, with no electrical charge.
An organism's role, or job, in its habitat.
Nitrogen compounds used for growth by plants and algae.
Nitrogen Cycle
The recycling of nitrogen in the environment in which nitrogen goes from a gas, to organic compounds in the soil, to proteins in a plant or nitrates, and then is again released into the atmosphere as a gas.
An element that lacks most of the properties of a metal; found to the right of the stair step line on the Periodic Table.
Non-point Source Pollution
A widely spread source of pollution that is difficult to link to a specific point of origin.
Non-renewable Resource
A resource that exists in a fixed amount or is used up more quickly than it can be replaced (ex: coal and oil).
Disease that occurs over a wide geographic area and affects a very high proportion of the population.
The relation between two different kinds of organisms in which one receives benefits from the other by causing damage to it. Parasite invades a host. Parasite benefits - host is harmed
( + - )
An organism that causes disease.
A horizontal row of elements in the periodic table.
Periodic Table
A chart of the elements showing the repeating pattern of their properties.
A nutrient needed by living things. High levels in water can cause excessive algae growth (eutrophication)
The process by which plants use water, along with carbon dioxide and energy from the sun, to make their own food.
Physical Change
A change in a substance that does not change its identity.
Physical Property
A characteristic of a pure substance that can be observed without changing it into another substance.
Tiny algae and animals that float in water and are carried by waves and currents.
Point Source Pollution
A specific source of pollution that can be identified.
A solid that forms from a solution during a chemical reaction.
Single-celled or simple multicellular eukaryotic organisms that generally do not fit in any other kingdom.
A small, positively charged particle in the nucleus of the atom.
Pure Substance
A material with a specific chemical composition; any substance that cannot be separated using physical means for instance, filtration, evaporation, distillation or chromatography.
Radioactive Dating
The process of determining the age of an object using the half-life of one or more radioactive isotopes.
A substance that enters into a chemical reaction; always on the left side of a chemical equation.
The ease and speed with which an element combines, or reacts, with other elements and compounds.
Relative Age
The age of a rock compared to the ages of rock layers. (oldest on bottom; youngest on top)

We use the Law of Superposition to help us find relative age.
Renewable Resource
A natural resource that can be replaced at about the same rate at which the resource is consumed.
The process by which cells break down simple food molecules to release the energy they contain.
River Basin
The entire geographical area drained by a river and its tributaries.
Sedimentary Rock
The type of rock that is made of hardened sediment;

fossils are only found in this type of rock.
Solar Energy
Energy from the sun that is converted into thermal or electrical energy.
A system that uses sound waves to calculate the distance to an object, and that gets its name from sound navigation and ranging.
Responsibility for conserving and restoring the Earth's resources for future generations.
Symbiotic Relationship
A close relationship between two organisms in which at least one of the organisms benefits.
The process by which plants give off water vapor through their leaves.
A measure of the clarity of the water. High turbidity = "dirty" water.
A place where an old, eroded rock surface is in contact with a newer rock layer.
Universal Solvent
A solvent in which almost any substance will dissolve - water.
Movement of nutrient-rich bottom water to the ocean's surface. This can occur far from shore but usually occurs along certain steep coastal areas where the surface layer of ocean water is pushed away from shore and replaced by cold, nutrient-rich bottom water.
Used to prevent one from getting a virus (flu shot).

A substance introduced into the body to stimulate the production of chemicals that destroy specific disease-causing viruses and organisms.
Valence Electrons
Outside electrons. Responsible for chemical reactions/compounds forming.

An electron in the outermost energy level of an atom; the electrons available to be lost, gained, or shared in the formation of chemical compounds.
An organism that transmits pathogens from one host to another but is not impacted/affected by the disease.
A tiny, nonliving particle that invades and then reproduces inside a living cell.
Water Cycle
The continuous process by which water moves from Earth's surface to the atmosphere and back.
The land area that supplies water to a river system.
Wind Turbine
A turbine that converts wind energy into electricity.
10% Rule
The amount of energy transferred from one trophic level to the next; the remainder is used for body processes or lost as heat to the environment.
Carbon Cycle
The biogeochemical process by which carbon is transferred between organisms and their environment.
The relationship between living things that depend on the same resources in the same place and at the same time.
A term used to describe a material that can be pulled out into a long wire.
Energy Pyramid
A diagram that shows the transition of energy from one trophic level to another.

10% rule (only 10% of energy is kept from each level)
A process where water bodies receive excess nutrients that stimulate excessive plant growth.
The carbohydrate formed in plants as a product of photosynthesis.
Limiting Factor
An environmental factor that limits population size.
The chemical processes that occur within a living organism in order to maintain life.
A process of the nitrogen cycle by which ammonia is converted to nitrites and then nitrates.
Noble Gases
The six elements on the periodic table that make up group 18. All elements are gases at room temperature and stable due to a full outer shell of electrons.
A substance formed as a result of a chemical reaction; always on the right side of a chemical equation.
The substance being dissolved in a solution.
The substance that dissolves another to form a solution.
Transition Metals
Groups 3 through 12 on the periodic table. All these elements are ductile and malleable, and conduct electricity and heat.
Trophic Level
The position an organism occupies within a food chain such as primary producers, primary consumers, secondary consumers, and tertiary consumers.
Geologic principle that states that the forces that act on the earth today are the same as the ones that have occurred throughout history.
pH level
measures how acidic or alkaline/basic a substance is. We want our water to have a pH of about 6.5-9.

0 is the most acidic. 14 is the most basic/alkaline.
Analogous structures
Organisms that do not share a common ancestor yet have similar functions.

Example: bird wing and bee wing (both help fly - not related)
vestigial structure
part of anatomy that once served used to ancient ancestors but no longer anymore (tailbone, appendix)
Mesozoic era
age of reptiles (dinosaurs)

ended due to a meteorite hitting the Earth, causing a thick layer of dust/dirt cloud (causing an ice age) due to the sun not being able to reach Earth's surface
Cenozoic era
age of the mammals (present)
when do eons-era-periods-epochs change?
catastrophic event or a change in life forms
Intrusive igneous rock
forms inside Earth due to magma cooling and hardening
Extrusive igneous rock
forms on the surface due to lava cooling and hardening
Metamorphic rock
forms due to both heat and pressure
symbiotic relationship where a predator attacks and eats prey

(most negative form of symbiotic relationships)