- accuracy
- the degree to which a measured value agrees with correct value for that measurement

- approximation
- an estimated value based on prior experience and reasoning

- classical physics
- physics that was developed from the Renaissance to the end of the 19th century

- conversion factor
- a ratio expressing how many of one unit are equal to another unit

- derived units
- units that can be calculated using algebraic combinations of the fundamental units

- English units
- system of measurement used in the United States; includes units of measurement such as feet, gallons, and pounds

- fundamental units
- units that can only be expressed relative to the procedure used to measure them

- kilogram
- the SI unit for mass, abbreviated (kg)

- law
- a description, using concise language or a mathematical formula, a generalized pattern in nature that is supported by scientific evidence and repeated experiments

- meter
- the SI unit for length, abbreviated (m)

- method of adding percents
- the percent uncertainty in a quantity calculated by multiplication or division is the sum of the percent uncertainties in the items used to make the calculation

- metric system
- a system in which values can be calculated in factors of 10

- model
- representation of something that is often too difficult (or impossible) to display directly

- modern physics
- the study of relativity, quantum mechanics, or both

- order of magnitude
- refers to the size of a quantity as it relates to a power of 10

- percent uncertainty
- the ratio of the uncertainty of a measurement to the measured value, expressed as a percentage

- physical quantity
- a characteristic or property of an object that can be measured or calculated from other measurements

- physics
- the science concerned with describing the interactions of energy, matter, space, and time; it is especially interested in what fundamental mechanisms underlie every phenomenon

- precision
- the degree to which repeated measurements agree with each other

- quantum mechanics
- the study of objects smaller than can be seen with a microscope

- relativity
- the study of objects moving at speeds greater than about 1% of the speed of light, or of objects being affected by a strong gravitational field

- scientific method
- a method that typically begins with an observation and question that the scientist will research; next, the scientist typically performs some research about the topic and then devises a hypothesis; then, the scientist will test the hypothesis by performing an experiment; finally, the scientist analyzes the results of the experiment and draws a conclusion

- second
- the SI unit for time, abbreviated (s)

- SI units
- the international system of units that scientists in most countries have agreed to use; includes units such as meters, liters, and grams

- significant figures
- express the precision of a measuring tool used to measure a value

- theory
- an explanation for patterns in nature that is supported by scientific evidence and verified multiple times by various groups of researchers

- uncertainty
- a quantitative measure of how much your measured values deviate from a standard or expected value

- units
- a standard used for expressing and comparing measurements