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scientific method

a series of steps followed to solve problems, including collecting data, formulating a hypothesis, testing the hypothesis, and stating conclusions

system

a set of particles or interacting components considered to be a distinct physical entity for the purpose of study

hypothesis

an explanation that is based on prior scientific research or observations and that can be tested

model

a pattern, plan, representation, or description designed to show the structure or workings of an object, system, or concept

theory

an explanation for some phenomenon that is based on observation, experimentation, and reasoning

quantity

something that has magnitude, size, or amount

SI

Le Systéme International d'Unités, or the International System of Units, which is the measurement system that is accepted worldwide

weight

a measure of the gravitational force exerted on an object; its value can change with the location of the object in the universe

derived unit

unit of measure that is a combination of other measurements

volume

a measure of the size of a body or region in three-dimensional space

density

the ratio of the mass of a substance to the volume of a substance; often expressed as grams per cubic centimeter for solids and liquids and as grams per liter for gases

conversion factor

a ratio that is derived from the equality of two different units and that can be used to convert from one unit to the other

dimensional analysis

a mathematical technique for studying dimensions of physical quantities

accuracy

a description of how close a measurement is to the true value of the quantity measured

precision

the exactness of a measurement

percentage error

a figure that is calculated by subtracting the accepted value from the experimental value, dividing the difference by the accepted value, and then multiply it by 100

significant figures

a prescribed decimal place that determines the amount of rounding off to be done based on the precision of the measurement

scientific notation

a method of expressing a quantity as a number multiplied by 10 to the appropriate power

directly proportional

the relationship between two variables whose ration is a constant value

inversely proportional

the relationship between two variables whose product is constant