Unit Summary: Measurements, Scientific Notation, Uncertainty, and Graphs

Base Unit

Defined in terms of a physical event/object; independent of other units.

Prefixes

Used to describe a wide range of measurements (e.g., kilo-, milli-, micro-).

Derived Units

Combinations of base units (e.g., speed, volume, density).

Accuracy

Closeness to accepted value.

Precision

Closeness of a set of measurements to each other.

Error

Difference between experimental and accepted values.

Percent Error

(\left\| \frac{\text{error}}{\text{accepted}} \right\| \times 100)

Significant Figures

Rules to express measured values with appropriate precision.

Scientific Notation

Expresses very large or small numbers as a coefficient between 1 and 10 times a power of 10 (a \times 10^{n}).

Dimensional Analysis

Systematic method using conversion factors to move from one unit to another.

Conversion Factor

Ratio of equal values with different units (e.g., 1\ \text{dozen} = 12\ \text{eggs}).

Interpolation

Estimating values between known data points.

Extrapolation

Estimating values beyond known data by extending the line.