The smallest particle of an element, consisting of protons, neutrons, and electrons. An atom can exist either alone or in combination with other atoms in a molecule.
The number of protons in the nucleus of an atom.
A substance made up of atoms of more than one element, chemically bonded to one another.
A branch of astronomy concerned with the origin, structure, and evolution of the universe.
The universe.
A substance made up of only one kind of atom. Unlike compounds, elements cannot be broken chemically into other substances.
Earth-centered.
Folklore inspired by geologic phenomena.
Sun-centered.
An unproven statement regarding an observed phenomenon.
A scientific principle that is shown always to be the case and for which no exceptions are deemed possible.
Astronomy, physics, chemistry, and the earth sciences.
A positively charged particle in an atom.
A set of principles and procedures for systematic study that includes observation; the formation of hypotheses, theories, and ultimately lawson the basis of such observation; and continual testing and reexamination.
A period of accelerated scientific discovery that completely reshaped the world. Usuallydated from about 1550 to 1700, the Scientific Revolution saw the origination of the scientific method and the introduction of such ideas as the heliocentric (Sun-centered) universe and gravity.
A general statement derived from a hypothesis that has withstood sufficient testing.
An area devoid of matter, even air.
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