Unit 1: Measurement in Science

Vocabulary and formulas related to measurement, errors, and density from Unit 1.

Physical quantity

A property that has a magnitude and a unit, such as length, area, volume, mass, or density.

Volume

The amount of space a substance occupies.

Mass

The amount of matter a body contains.

Zero error

Occurs when an instrument gives a non-zero reading when the true reading is zero.

Parallax error

Occurs when the eye is not directly opposite to the mark and the line of sight is not perpendicular to the scale.

Density

The mass of a substance per unit volume.

Density ($D$) Formula

$$D = \frac{M}{V}$$

Mass ($M$) Formula

$$M = D \times V$$

Volume ($V$) Formula

$$V = \frac{M}{D}$$

Floating condition

For a solid to float on a liquid, the density of the solid must be less than the density of the liquid.

Average density

The determining factor for whether complex objects like ships float; a ship floats because its average density is less than the density of water.

General density rule of states

The density of a solid is generally higher than the density of a liquid, which is higher than the density of a gas.