Scientific Enquiry - Observation and Measurement

Scientific observations can be qualitative (describing qualities using the five senses) or quantitative (using numerical values and units, such as $25.0 \text{ cm}$).

Measurements must always include a magnitude and a unit. The SI (International System of Units) includes the meter ($m$) for length, kilogram ($kg$) for mass, and second ($s$) for time.

Accuracy refers to how close a measurement is to the true value, while Precision refers to how close a series of measurements are to each other.

Parallax error is a common mistake in measurement caused by viewing a scale at an angle. To avoid this, always read at eye level and perpendicular to the scale.

When measuring liquid in a graduated cylinder, measurements should be taken from the bottom of the meniscus (the curve of the liquid surface).

Independent variables are the factors we change, while Dependent variables are the factors we measure (e.g., measuring the change in temperature $\Delta T$ over time $t$).

Derived units are units calculated from SI base units, such as area ($m^2$), volume ($m^3$), and density ($kg/m^3$).