Units

Units

Why use units 

• Why are units important when making measurements?
• Think how confusing it would be if some one were to say walk five in that direction.
• Your immediate reaction would be five what, meters, feet, miles, yards?
• All measurements depend on units that serve as reference standards.

Unit system

• What units are used in science?
• metric units are used for all science measurements.
• It’s used because of its simplicity and ease of use, because all metric units are based on 10 or multiples of 10.
• This fact makes it very easy to convert between units.

Basic units

• what is the basic unit for measuring length, volume, and mass?
• the meter is the basic unit of measurement for length, the liter for volume, and the gram for mass.

Prefixes

• giga- (G-)109 1 billion
• mega- (M-)106 1 million
• kilo- (k-)103 1 thousand
• hecto- (h-)102 1 hundred
• deka- (da-)**10 1 ten
• basic units (L, g, m)
• deci- (d-)10-1 1 tenth
• centi- (c-)10-2 1 hundredth
• milli- (m-)10-3 1 thousandth
• micro- (µ-)10-6 1 millionth
• nano- (n-)10-9 1 billionth