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An educated guess that attempts to explain an observation or answer a question


guess correctly, to find out by reasoning; to arrive at a conclusion on the basis of thought; to hint, suggest, imply

controlled experiment

experiment that tests the effect of a single variable


something in an experiment that can change

independent variable

variable that is changed in an experiment

dependent variable

the variable that is measured in an experiment


variable that is not changed in an experiment

critical thinking

Thinking that does not blindly accept arguments and conclusions


the information gathered from observations.

Earth science

The study of earth and space; includes geology, meteorology, astronomy, and oceanography

life science

The study of living things


represents an idea, event, or object to help people better understand it

physical science

the study of matter and energy


the study of the natural world

scientific law

A theory that has been tested by and is consistent with generations of data

scientific theory

A well tested concept that explains a wide range of observations


an organized group of parts that work together to form a whole


tools and skills people use to meet their basic needs


a quantity that has both a number and a unit


the exactness of a measurement


How close a measurement is to the true value


an explanation of an observation


the international system of units


The basic SI unit of length


the amount of space an object takes up


the amount of matter in an object


SI unit for mass, one thousand grams


the vertical force exerted by a mass as a result of gravity


SI unit for temperature, - fundamental SI unit of temperature where zero degrees Kelvin is equal to absolute zero.


amount of change of one measurement in a given amount of time


a set of data arranged in rows and columns


A diagram that shows how two variables are related.

line graph

shows the relationship between two variables, shows change over time

bar graph

a graph that uses horizontal or vertical bars to display data

circle graph

A graph of data where the entire circle represents the whole or 100%, shows parts of a whole


method of making an educated guess at a measurement, An approximate calculation of quantity

J.J. Thompson

used the cathode ray tube to discover the electron


(1743-1794) father of modern chemistry - co discovered oxygen and hydrogen, introduced metric system, invented first periodic table. Beheaded in French Revolution

Ernest Rutherford

British physicist discovered the nucleus, gold foil experiment- fired negative ions at thin sheet of gold foil, some particles were deflected almost as if it hit something solid


discovered the neutron, introduced Law of Conservation of Matter

John Dalton

discovered the atomic theory, or the idea that everything was made up of atoms, created first model of the atom

Periodic Table of Elements

the scientific chart that contains an arrangement of all known elements into a particular order based upon the number of protons and other properties of each element.

How many known elements in the Periodic Table of Elements


How many elements in the Periodic Table of Elements are naturally occuring



elements on the periodic table with high luster, good electrical conductivity, malleability, and loosely held valence electrons.


elements on the periodic table that are usually dull in appearance, poor conductors of heat and electricity, gases at room temperature

Transitional metals

elements on the periodic table that are used because they have high melting points and are hard.


elements on the periodic table that have properties of both metals and nonmetals

Noble gases

non-metallic elements on the periodic table which contain the most stable and nonreactive elements (also called the inert gases because they do not participate in many chemical reactions)

Atomic Number

the number of protons in the nucleus of an atom

Atomic Mass

total mass of the protons and neutrons in an atom, measured in atomic mass units

Chemical Symbol

a one or two letter representation of an element, the abbreviation for the name of an element

Number of protons

equals number of electrons

Number of neutrons

Mass number - atomic number

Number of electrons

equals the number of protons


that which has mass and occupies space


the smallest unit of matter that has the characteristics of an element; consists of three main types of subatomic particles: protons neutrons and electrons.


a molecule composed of one kind of atom; cannot be broken into simpler units by chemical reactions.

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