SI System Advantage of SI system is that it is based upon the decimal system Units can be expressed in terms of small or large units by changing the prefix. Prefixes are the same for all units

Magnitude and prefix ,001 kilo hecta deka deci centi milli micro

Very small units 0.000,000, ,000,000,001 nano pico

SI unit of mass is the kilogram Only unit where base unit has a prefix 1kg=1000g= 10 3 g

SI unit of length Meter Kilometer used to measure long distances Smaller distances use centimeter 1/100, or millimeter 1/1000, or micrometer 1/

SI Unit of Area Area not a fundamental unit, derived unit, derived from length Unit m 2 used or cm 2

SI Unit of Volume Derived from length m 3 for smaller volumes cm 3 Also use term liter 1ml=1cm 3 1 liter = 1000 cm 3

SI Unit of Time Unit of time is second (s) Smaller units of time millisecond 1/1000 s, or microsecond 1/ s Larger units use non-SI, hours, days, years

Exponential Notation Scientists sometimes deal with very large or very small numbers. Use exponential notation to describe these.

Examples Size of an atom 0.000,000,000,1m or 1x m. Size of the Sun m or 1x10 9 m

Density Density is made up of tow units, mass and volume Density= mass/volume D=m/v Usually use units g/mL

Energy Energy is the ability to change matter either physically or chemically Two types of energy- Potential and kinteic

Potential Energy Energy of position or arrangement Ex. Skier on top of a mountain, a piece of firewood.

Kinetic Energy Energy due to motion Ex. skier going down a mountain, a burning log on a fire

Temperature and Heat When two objects of different temperature are brought together heat is transferred between them Temperature-a measure of the kinetic energy of the molecules, tells us which direction heat will travel

Heat Heat-energy flowing from a warmer object to a cooler object.

Temperature SI unit of temperature is the Kelvin (K). 0 K is the coolest temperature theoretically possible, when all motion stops. Degrees Celsius °C more common.

K and °C have same magnitude but different starting points 0 °C is melting point of water 0K = °C

SI Unit of Heat SI unit of heat is the Joule (J) calorie is a more common unit (cal) 1 cal = J 1 cal amount of heat needed to raise 1 mL of water 1 °C. Food Calorie is actually 1 kcal