Lecture Review: Measurements, Unit Systems, Significant Figures, and Social Inequality

Flashcards covering scientific measurement concepts, SI prefixes, sig fig calculation rules, density, temperature scales, and social psychology concepts on upward mobility.

Base 12 System

A historical numerical counting system derived from using the thumb to count the three joints on each of the remaining four fingers on one hand.

SI Units

The International System of Units based on seven fundamental physical quantities: length, mass, time, temperature, electric current, amount of substance, and luminous intensity.

Micro- ($\mu$)

A metric decimal prefix indicating a factor of $10^{-6}$, or one millionth of a base unit.

Mega- ($\text{M}$)

A metric decimal prefix indicating a factor of $10^{6}$, or one million times a base unit.

Dimensional Analysis

A systematic mathematical technique used to convert between units by multiplying or dividing by conversion factors.

Density

An intrinsic physical property of matter calculated as mass divided by volume ($\text{Density} = \frac{\text{mass}}{\text{volume}}$).

Kelvin Scale

An absolute temperature scale used in science that omits degree symbols and relates to the Celsius scale by the formula $\text{K} = {^\circ\text{C}} + 273.15$.

Exact Quantity

A value derived from counting discrete objects or exact definitions that contains zero measurement uncertainty (e.g., $26$ letters in the alphabet, $60$ seconds in a minute).

Estimated Digit

The rightmost recorded digit in a scientific measurement, representing an estimated value or guess between scale graduations.

Significant Figures

All digits in a measured quantity that carry precision meaning, ending with the single estimated or uncertain digit.

Sig Fig Rule for Addition and Subtraction

A calculation rule dictating that the final result must be rounded to match the measurement containing the fewest decimal places.

Sig Fig Rule for Multiplication and Division

A calculation rule dictating that the final result must be rounded to match the measurement containing the fewest total significant figures.

Upward Mobility

An economic statistic describing the probability or rate at which a generation earns higher relative income than their parents.

Raj Chetty

A Harvard economist who analyzed IRS data to demonstrate that upward economic mobility in the United States has steadily declined across decades since the 1940s.