Advertisement Upgrade to remove ads


The study of the Earth's surface and interior


A possible explanation for a observation or phenomenon, developed from available info and used as a basis for testing

Astronomical Unit

The average distance between Earth and the sun, about 150 million kilometers


a group of millions, even billions, of stars held together by gravity


A large cloud of dust and gas in space

Planetary Accretion

The gradual growth of a planet by collision and sticking

Super Nova

Brilliant burst of light that follows the collapse of the iron core and explosion of a massive star


The very thin outer layer of the Earth, above the mantle composed of a rigid later of lighter rocks


the infinitely small space that all matter in the universe existed before the Big Bang


The study of the universe


Part of the experiment that is the same

Light Year

The distance that light travels in a year, about 9.5 trillion kilometers

Local Group

group of nearby galaxies that the milky way belongs to

Oblate Spheroid

shape of the earth, a slightly flattened sphere

Big Bang

Theory of creation of Universe by instant expansion of an extremely small piece of matter of extremely high density and temperature


Light made by meteoroid as it passes through Earth's atmosphere


A rocky or icy fragment that travels through space


The part of a large meteoroid that survives its trip through the atmosphere and strikes Earth's surface


The thickness of Earth's layers, located between the outer core and the Earth's crust, composed mostly of compounds rich in iron, silicon, and magnesium


Volcano located in Indonasia that erupted in 1815 and caused the Year without a Summer in New England during 1816


The scientific study of the ocean and seas


Part of an experiment that is changed. What is being tested


Unit of length. 1000 meters

Virgo Cluster

The closest cluster of galaxies to our local cluster. Contains roughly 2000 galaxies


during planetary accretion, when blobs of matter collide to form and object 1 -10 km in size


A substance composed of atoms that are chemically alike and that cannot be broken down into simpler parts


A solid, rocklike mass that revolves around the sun.

Inner Core

The solid, inner most layer of the Earth, composed of iron and nickel under extremely high pressure and temperature


Located in Siberia, site where a asteroid struck in 1908 with the power of 1000 atmonic bombs


The study of processes that govern Earth's atmosphere


An explanation based on observation, reasoning, and experimentation, especially one that has been tested and confirmed as a general explanation for a phenomena that has been observed


1) Round 2) Orbits the Sun 3) cleared most of its orbit of derbis

Nebular Hypothesis

The theory for how the solar system formed


The change from water vapor to liquid water


a mass of rock, ice, dust, and gas traveling around the sun usually in a highly eccentric orbit

Solar System

The sun and its family of orbiting planets, moods, and solar system debris

Outer Core

The layer of the Earth's interior located between the inner core and mantle, composed of iron and nickel in a liquid state

White Nights

Occurred in 1908 in Northern Europe for three nights after the asteroid stuck Tunguska

Apparent Magnitude

the brightness of a star when viewed from Earth


A group of stars that form a pattern in the sky


the solid part of the earth consisting of the crust and outer mantle


the lower layer of the crust

Magnetic Field

The energy field created by the spinning of the inner and outer cores.

Proxima Centauri

Other than the Sun the next closest star to Earth, just over 4 lightyears away

4.567 Billion Years

age of the earth

13.7 Billion Years

age of the universe

Condensation Nuclei

solid surfaces around which a gas condenses


The layer of the atmosphere we live in. The temperature decreases the higher you go


a form of oxygen that has three oxygen atoms in each molecule instead of two 03. protects us from dangerous ultraviolet radiation from the sun


The solar radiation (energy from the sun) that reaches Earth.

Dew Point

The temperature at which saturation occurs and condensation begins; a measure of the amount of water vapor in the air.


a change directly from the solid to the gaseous state or gaseous to solid without becoming liquid

Condensation Nuclei

Microscopic particles on which water vapor condenses to form cloud droplets.

Dry Adiabatic Lapse Rates

Rising unsaturated air cooling at a rate of about 1 degree Celsius for every 100m it rises.

Tropic of Cancer

a line of latitude about 23 degrees North of the equator

Tropic of Capricorn

a line of latitude about 23 degrees South of the equator

Mare's Tail

Type of cirrus cloud, indicates rain in 24 hours


Clouds that form in low, horizontal layers, cover all or most of sky


The layer of Earth's atmosphere that extends from the troposhere to the mesosphere; concentrations of ozone cause it to get warmer as you go up in this layer.


The transfer of energy through space in the form of visible light, ultraviolet rays and other types of electromagnetic waves

Specific Humidity

The amount of water vapor in the air at a given time and place; expressed as the number of grams of water vapor per kilogram of air.


The maximum amount of water that can be present in the air at a certain temperature. Warmer the temp, higher the capacity


An instrument that works on the principle that evaporation causes cooling.


moisture from the air that forms drops on cool surfaces


High-altitude clouds that are thin, feathery tufts of ice crystals.

Moist Adiabatic Lapse Rates

Is the rate at which saturated air cools as it rises, .5 degrees Celsius for every 100m of rising


moisture frozen on or in a surface; feathery crystals of ice formed when water vapor in the air condenses at a temperature below freezing

Autumnal Equinox

Occurs in September, in the northern hemisphere, and marks the beginning of fall in the Northern Hemisphere

Winter Solstice

begins on Dec. 21st in northern hemisphere; northern hemisphere is tilted away from the sun, so it's the coldest time of the year

Crepuscular Ray

Rays of light that shine through clouds


a circle of light around the sun or moon


The layer of the Earth's atmosphere that extends from the stratosphere to the thermosphere, characterized by decreasing temperatures.


The transfer of heat energy through collisions of the atoms or molecules of a substance, the direct transfer of heat from one substance to another substance that it is touching

Relative Humidity

A comparison of the actual amount of water vapor in the air with the maximum amount if water vapor that can be present in air. Specific Humidity/Capacity


the change of a substance from a liquid to a gas

Latent Heat

heat absorbed or given off during a change of phase at a constant temperature


A stratus cloud located on the ground


Thick, fluffy clouds with flat bases, formed by vertically rising air currents

Vernal Equinox

the day of the year that marks the beginning of spring in the northern hemisphere


Chlorinated Fluorocarbons are chemicals that break down the ozone layer


High clouds.

Sun Dog

Rainbows located to the right and left of the sun. Seen with cirrostratus clouds, indicate rain is coming


The layer of Earth's atmosphere above the mesosphere, characterized by increasing temperatures with altitude.


The transfer of heat energy in a liquid or gas through the motion of the liquid or gas caused by differences in density


The condition in which the air is holding as much water vapor as possible at a given temperature and pressure.


The change from water vapor to liquid water

Water Vapor

An invisible gas formed when water reaches 100 degrees Celsius and evaporates

Condensation Level

The altitude at which water vapor begins to condense.

Summer Solstice

On June 21, it is the longest day in the Northern Hemisphere due to the fact that the sun is directly over the tropic of Cancer


light wispy precipitation that evaporates before it reaches the ground (especially when the lower air is low in humidity)


Dark rain clouds.


Caused by humans

Freezing Rain

raindrops that freeze after they hit the ground or other cold surfaces


precipitation of ice pellets when there are strong rising air currents


a type of precipitation that forms when it falls through a layer of freezing air


on the side exposed to the wind


the side of something that is sheltered from the wind

air pressure

the force that air exerts per unit area

aneroid barometer

an instrument that measure air pressure, An instrument that measures changes in air pressure without using a liquid. Changes in the shape of an airtight metal box cause a needle on the barometer dial to move.

pressure gradient force

Drives air from areas of higher barometric pressure to areas of lower barometric pressure, causing winds.


a line on a weather map that joins points having the same barometric pressure


an area in which the barometric pressure is greater than that of the surrounding air


an area in which the barometric pressure is lower than that of the surrounding air


an instrument that measures wind speed

Coriolis Effect

The way Earth's rotation makes winds in the Northern Hemisphere curve to the right and winds in the Southern Hemisphere curve to the left.

Air Mass

a body of air that has about the same temperature and moisture throughout


a boundary between two air masses of different density, moisture, or temperature

Convection Current

the movement of a fluid, caused by differences in temperature, that transfers heat from one part of the fluid to another

Occluded Front

a front where a warm air mass is caught between two colder air masses and brings cool temperatures and large amounts of rain and snow

Jet Stream

narrow belt of strong winds that blows near the top of the troposphere across the US

Wind Vain

an instrument used to determine the direction that the wind is blowing


the resistance encountered when one body is moved in contact with another. Slows down the speed of wind when it flows over land

Cold Front

forms when cold air moves under warm air which is less dense and pushes air up

warm front

moving weather front along which a warm air mass slides over a cold air mass, producing stratiform clouds and precipitation


Area of high pressure where wind will move away from, associated with dry and nice weather and air that is sinking


Area of low pressure where wind will move towards, associated with cloudy and rainy weather and air that is rising

Mercury Barometer

An instrument that measures changes in air pressure, consisting of a glass tube partially filled with mercury, with its open end resting in a dish of mercury. Air pressure pushing on the mercury in the dish forces the mercury in the tube to be higher.


not formed from living things or the remains of living things


property of a mineral, least helpful


The way a mineral reflects light

Specific Gravity

the ratio of a mineral's weight compared with the weight of an equal volume of water


formed from living things or the remains of living things


a mineral's resistance to being scratched


color of a mineral's powder left behind on a streak plate


the process of becoming hard or solid by cooling Ex: magma into an igneous rock

Naturally Occurring

not made-made


the manner in which a mineral breaks along either curved or irregular surfaces


tendency of a mineral to break along flat surfaces


the process whereby heat changes something from a solid to a liquid


the laying down of sediments on the ocean floor


The process by which sediments are pressed together under their own weight to form sedimentary rocks


The process in which minerals precipitate into pore spaces between sediment grains and bind sediments together to form rock.


the process of turning something into rock


The breaking down of rocks and other materials on the Earth's surface.


The removal and transport of weathered material by natural processes


the force applied to a unit area of surface, forces water out between grains of sediment in the lithification process, also can cause rocks to metamorphose


most abundant group of minerals, made up of compounds that contain silicon and oxygen

Silica Tetrahedron

Basic building block of silicate minerals, made up of four oxygen atoms and 1 silicon aton

Metamorphic Rock

A type of rock that forms from an existing rock that is changed by heat, pressure, or chemical reactions

Igneous Rock

a type of rock that forms from the cooling of molten rock at or below the surface

Sedimentary Rock

A type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together


a naturally occurring, inorganic, solid that has a crystal structure and a definite chemical composition


molten rock located below the surface


molten rock that has reached the surface


type of fracture with curved breaks, like what happens with thick glass or the bottom of a bottle, shell shaped

Double Refraction

property exhibited by transparent minerals that produce a double image of any object viewed through them, Ex: The mineral Iceland Spar


an organism that grows, feeds and is sheltered on or in a different organism while contributing nothing to the survival of its host


any organism with a round mouth and no jaw


organisms that live is fresh water and spawn in the ocean

See More

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again


Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording