Measurement

Direct Measurements

Measurements that can be directly measured, such as length, mass, temperature, time, and volume.

Length

The distance between two points, measured using a metric ruler in meters (m).

Mass

The amount of matter in an object, measured using a balance in kilograms (Kg).

Temperature

The degree of hotness or coldness, measured using a thermometer in degrees Celsius (°C).

Time

The duration or interval between events, measured using a stopwatch or timer in seconds (S).

Volume

The amount of space occupied by an object, measured using a graduated cylinder in liters (L) (not an SI unit).

Indirect (Derived) Units

Units that require two or more measurements to calculate, such as area, volume, and density.

Area

The measure of the surface enclosed by a shape, calculated by multiplying length and width (a = Lw).

Volume

The measure of the space occupied by a three-dimensional object, calculated by multiplying length, width, and height (v = Lwh).

Density

The mass per unit volume of a substance, calculated by dividing mass by volume (density = m/v).

SI (International System of Units)

A system of measurement based on powers of 10.

Prefixes

Prefixes used in the SI system to indicate multiples or fractions of the base unit.

Giga- (G)

Represents one billion or 10^9.

Mega- (M)

Represents one million or 10^6.

Kilo- (K)

Represents one thousand or 10^3.

Hecta- (H)

Represents one hundred or 10^2.

Deca- (da)

Represents ten or 10^1.

Base

Represents one or 10^0.

Deci- (d)

Represents one-tenth or 10^-1.

Centi- (c)

Represents one-hundredth or 10^-2.

Milli- (m)

Represents one-thousandth or 10^-3.

Micro- (µ)

Represents one-millionth or 10^-6.

Nano- (n)

Represents one-billionth or 10^-9.