CH 1-3

Measurement

Scientific notation is used for very large or very small numbers

3.0 X 10

n

SI units of measure

• Scientist use a set of measuring units called SI or International System of Units

• This helps scientist from different countries understand each others research

Basic Units of Measure

Length Meter - M

Mass Kilogram- kg

Temperature Kelvin- K

Time Second- s

Amount of substance Mole- m

Electric current Ampere- A

Luminous intensity Candela- cd

Derived UnitsArea m

Volume m

Density kg/m

Speed (V) m/s

Energy- Joule (J) kg*m/s

Force- Newton (N) kg*m/s

Acceleration (a) m/s

2

3

2

2

2

2

2

SI PrefixesPrefix Symbol Multiple Meaning

giga G 1,000,000,000 billion

mega M 1,000,000 million

kilo k 1,000 thousand

deci d .1 tenth

centi c .01 hundredth

Limits to Measurement

• Significant figures show how accurately something has been measured.

• The precision of a calculated answer is limited to the precise measure with the least significant figures.

Accuracy

• Is the closeness of a measurement to the actual value of what is being measured

• TEMPERATURE

• To convert temperature to Kelvins you add 273 to C

Problems

• What is the boiling point of water in Kelvins?

• Convert 12Kg to g

• Convert 5mL to L

• You get to school at 7:23 and leave at 3:45 how long were you at school?

• You have a temperature of 101 F how many Kelvins is it?