Measurements in Experiments Flashcards

Vocabulary flashcards covering SI base units, standard definitions, scientific notation, accuracy, precision, parallax, and significant figures based on physics lecture notes.

SI Base Units

The seven standard base measurements in the International System of Units, each describing a single dimension such as length, mass, or time.

Meter (m)

The SI base unit of length, defined as a basic distance and currently standardized as the distance traveled by light in a vacuum in $3.33564095 \times 10^{-9}\,s$.

Kilogram (kg)

The SI base unit of mass, representing the quantity of matter and currently standardized as the mass of a specific platinum-iridium alloy cylinder.

Second (s)

The SI base unit of time, representing the duration of events and currently standardized as $9\,192\,631\,770$ times the period of a radio wave emitted from a cesium-133 atom.

Ampere (A)

The SI base unit of electric current, defined as the flow of electric charge.

Kelvin (K)

The SI base unit of temperature, representing a measure of hot or cold.

Mole (mol)

The SI base unit of amount of substance, representing the number of particles.

Candela (cd)

The SI base unit of luminous intensity, representing the brightness of light.

Derived Units

Units of measurement formed by combining the seven base SI units through multiplication or division, such as meters per second ($\text{m/s}$) for speed.

SI Prefixes

Prefixes attached to the front of SI units to symbolize specific powers of $10$, making units larger or smaller.

Scientific Notation

A shorthand method of writing numbers expressed as a value between $1$ and less than $10$ multiplied by a power of $10$.

Standard Notation

The traditional full expression of a number written out with digits and decimal places rather than power-of-ten exponents.

Accuracy

A description of how close a measurement is to the correct or accepted value of the quantity measured.

Precision

The degree of exactness of a measurement.

Uncertainty

A numeric measure of confidence in a measurement or result, where a lower uncertainty indicates greater confidence.

Parallax

An apparent shift in the position of an object when viewed from different locations or angles.

Significant Figures

The digits in a measurement that are known with certainty plus the first digit that is uncertain.

Rule for Addition and Subtraction with Significant Figures

The calculation rule stating that the final answer must be rounded to the first column from the left containing an estimated digit.

Rule for Multiplication and Division with Significant Figures

The calculation rule stating that the final answer has the same number of significant figures as the measurement having the smallest number of significant figures.

Precise and Accurate Measurement

A state where experimental measurements are both close to one another (precise) and close to the expected or true value (accurate).

Precise but Not Accurate Measurement

A state where experimental measurements are close to one another (high precision) but far from the expected or true value (low accuracy).