Systéme International d’unités (SI)

International System of Units

otherwise known as the metric system....

General Information

International System of Units (SI) is a version of the metric system.

SI is based on the powers of 10.

General Information

Scientist world-wide have agreed to use SI to allow comparison of data and communication of results with each other.

LengthDef: distance between two points

Basic Unit: meter (m)

Common Units: kilometer (km), meter (m), centimeter (cm), millimeter (mm)

LengthMeasurement tool: ruler, measuring tape, meter stick

Common Conversions: 1 km = 1000 m, 1 m = 100 cm, 1 m = 1000 mm, 1 cm = 10 mm

Meter stick

MassDef: the amount of matter an object contains.

Basic Unit: kilogram (kg)

Common Units: kilogram (kg), gram (g), milligram (mg)

Mass

Measurement tools: pan balance, triple-beam balance, electronic balance

Common conversions: 1 kg = 1000 g, 1 g = 1000 mg

Mass

Weight: the pull of gravity on the mass of an object.

Pan balance

Triple-beam balance

Electronic balance

VolumeDef: amount of space an object takes up

Basic unit: liter (L)

Common units: liter (L), milliliter (mL), cubic centimeter (cm3)

Volume

Measurement tools: graduated cylinder, ruler (for rectangular solids)

Common conversions: 1 L = 1000 mL, 1 mL = 1 cm3

Volume - Reading a graduated cylinder

Look at liquid level at eye level.

Read at the bottom of the meniscus.

Meniscus - the bottom of the curve of liquid in a graduated cylinder.

Looking at graduated cylinder witha

meniscus

Volume - How to determine

Rectangular solids: volume is determined by measuring height, width, and length and multiplying them together.

Rectangular solid measurements

Volume - How to determine

Irregular solids: displacement of liquid (how much the water rises when an object is placed in the water.)

Volume by displacement

TimeBasic unit: second (s)

Common units: second (s), minute (min), hour (hr)

Measurement tools: clock, watch

Time

Common conversions: 1 hr = 60 min, 1 min = 60 s, 1 s = 1000 ms

TemperatureDef: a measurement of the average kinetic energy of the molecules in an object.

Basic unit: Kelvin (K)

Common Units: Kelvin (K), Celsius (°C)

Temperature

Measurement tool: thermometer

Common conversions: 0 K = -273°C, 0°C = 273 K

Temperature

Common temperatures: Water freezes - 0°C, Water boils - 100°C, Human body temperature - 37°C, Room temperature - 20°C