A mixture in which various components can be seen as individual substances

A chart in which all known elements are listed in order of atomic number

the branch of chemistry dealing with the relations between the physical properties of substances and their chemical composition and transformations.

the branch of chemistry, originally limited to substances found only in living organisms, dealing with the compounds of carbon.

The branch of chemistry that deals with inorganic compounds.

the subdivision of chemistry dealing with the qualitative and quantitative determination of chemical components of substances.

The scientific study of the origin of the Earth along with its rocks, minerals, land forms, and life forms, and of the processes that have affected them over the course of the Earth's history.

Relating to rocks or minerals formed by the cooling and hardening of magma or molten lava. Basalt and granite are examples of igneous rocks.

Relating to rocks formed when sediment is deposited and becomes tightly compacted.

Relating to rocks that have undergone metamorphism. Metamorphic rocks are formed when igneous, sedimentary, or other metamorphic rocks undergo a physical change due to extreme heat and pressure.

- Any of numerous substances that can be shaped and molded when subjected to heat or pressure.

the layer of the Earth between the crust and the core. It is about 2,900 km (1,798 mi) thick

The central or innermost portion of the Earth, lying below the mantle and probably consisting of iron and nickel. It is divided into a liquid outer core, which begins at a depth of 2,898 km (1,800 mi), and a solid inner core, which begins at a depth of 4,983 km (3,090 mi).

The solid, outermost layer of the Earth, lying above the mantle. ◇ The crust that includes continents is called continental crust and is about 35.4 to 70 km (22 to 43.4 mi) thick.

sub-layers of the earth's crust (lithosphere) that move, float, and sometimes fracture and whose interaction causes continental drift, earthquakes, volcanoes, mountains, and oceanic trenches

process of wearing away rocks by wind, water, or ice

the science that deals with the material universe beyond the earth's atmosphere.

A large, spherical celestial body consisting of a mass of gas that is hot enough to sustain nuclear fusion and thus produce radiant energy.

any of the thousands of small bodies of from 480 miles (775 km) to less than one mile (1.6 km) in diameter that revolve about the sun in orbits lying mostly between those of Mars and Jupiter.

the distance traversed by light in one mean solar year, about 5.88 trillion mi. (9.46 trillion km): used as a unit in measuring stellar distances.

- a large system of stars held together by mutual gravitation and isolated from similar systems by vast regions of space.

the explosion of a star, possibly caused by gravitational collapse, during which the star's luminosity increases by as much as 20 magnitudes and most of the star's mass is blown away at very high velocity, sometimes leaving behind an extremely dense core.

a star, approximately the size of the earth, that has undergone gravitational collapse and is in the final stage of evolution for low-mass stars, beginning hot and white and ending cold and dark

a theoretical massive object, formed at the beginning of the universe or by the gravitational collapse of a star exploding as a supernova, whose gravitational field is so intense that no electromagnetic radiation can escape.

a hypothetical form of matter invisible to electromagnetic radiation, postulated to account for gravitational forces observed in the universe.

A form of energy hypothesized to reside in the structure of space itself, responsible for the accelerating expansion of the universe. Dark energy theoretically counterbalances the kinetic energy of the universe's expansion, entailing that that the universe has no inherent curvature, as astronomical observations currently suggest.