B.International System of measurement

Vocabulary flashcards covering SI base units, prefixes, mass versus weight, derived units, volume, energy, and density.

International System of Units (SI)

An international system of units, also known as Système Internationale d'Unités, established so that scientists around the world can communicate efficiently.

Base SI Units

The seven fundamental units of SI: meter (length), kilogram (mass), second (time), mole (amount), kelvin (temperature), ampere (electrical current), and candela (luminous intensity).

Kilogram (kg)

The SI base unit of mass, defined by international convention as the quantity of mass of a platinum-iridium cylinder kept in a vault in France.

Mass

A measure of a body's inertial property or how much matter it contains.

Weight

A measure of the force exerted on a body by gravity or the force needed to support it, with the SI unit of newton ($\text{N}$).

Newton (N)

The SI unit of weight or force, defined in a particular reference frame as the force that gives a body an acceleration equal to the local acceleration of free fall.

Derived SI Units

Combinations of SI base units formed by multiplying or dividing units, such as square centimeters for area or cubic meters for volume.

Volume

The amount of space that a given substance occupies, defined geometrically as $\text{length} \times \text{width} \times \text{height}$ with the derived unit $\text{m}^3$.

Liter (L)

A unit of volume equal to $\frac{1}{1,000}$ of a cubic meter ($1\,dm^3$ or $1,000\,cm^3$), which is slightly larger than $1\,\text{US quart}$.

Milliliter (mL)

A unit of volume equal to $\frac{1}{1,000}$ of a liter, representing the exact same volume as $1\,\text{cubic centimeter}$ ($1\,cm^3$).

Energy

The ability to perform work, such as moving a box of books, with a derived unit of $\text{kg} \cdot \text{m}^2/\text{s}^2$.

Joule (J)

The redefined SI unit for energy, equivalent to $\text{kg} \cdot \text{m}^2/\text{s}^2$.

Calorie (cal)

An older unit of energy widely used in chemistry, where $1\,\text{cal} = 4.184\,\text{J}$.

Calorie (capital C)

The food industry unit for energy, equal to a kilocalorie ($1\,\text{Calorie} = 1,000\,\text{calories}$ or $1\,\text{kcal}$).

Density

A physical property defined as mass divided by volume ($\text{density} = \frac{\text{mass}}{\text{volume}}$), describing the amount of matter in a given space.

Giga- (G)

An SI prefix representing a multiplicative factor of $1,000,000,000 \times$ ($10^9 \times$).

Mega- (M)

An SI prefix representing a multiplicative factor of $1,000,000 \times$ ($10^6 \times$).

Kilo- (k)

An SI prefix representing a multiplicative factor of $1,000 \times$ ($10^3 \times$).

Deca- (D)

An SI prefix representing a multiplicative factor of $10 \times$ ($10^1 \times$).

Deci- (d)

An SI prefix representing a multiplicative factor of $\frac{1}{10} \times$ ($10^{-1} \times$).

Centi- (c)

An SI prefix representing a multiplicative factor of $\frac{1}{100} \times$ ($10^{-2} \times$).

Milli- (m)

An SI prefix representing a multiplicative factor of $\frac{1}{1,000} \times$ ($10^{-3} \times$).

Micro- (\mu)

An SI prefix represented by the Greek lowercase letter mu, with a multiplicative factor of $\frac{1}{1,000,000} \times$ ($10^{-6} \times$).

Nano- (n)

An SI prefix representing a multiplicative factor of $\frac{1}{1,000,000,000} \times$ ($10^{-9} \times$).

2008 CDC Report on Weight

A report from the US Centers for Disease Control and Prevention stating that $73\%$ of Americans were overweight or obese, including $19\%$ of children aged 6–11 and $18\%$ of adolescents aged 12–19.