Introduction to Introduction to ScienceScience

Theories & LawsTheories & Laws

►Scientific TheoryScientific Theory Explanation that has been tested by Explanation that has been tested by

repeated observations (experiments)repeated observations (experiments) Constantly questioned and must pass Constantly questioned and must pass

three teststhree tests►1) Theories must explain observations simply 1) Theories must explain observations simply

& clearly& clearly►2) Experiments that illustrate the theory must 2) Experiments that illustrate the theory must

be repeatablebe repeatable►3) You must be able to predict from a theory3) You must be able to predict from a theory

►Scientific lawScientific law States a repeated observation about States a repeated observation about

naturenature

*** Theories and Laws are NOT absolute *** Theories and Laws are NOT absolute ******

MeasurementMeasurement

►Use a standard system of units called Use a standard system of units called the SI unitsthe SI units

►A decimal system (0.0) that uses the A decimal system (0.0) that uses the number 10 as a base unitnumber 10 as a base unit

►SI prefixes are use for very large and SI prefixes are use for very large and very small measurementsvery small measurements

►They are all multiples of tenThey are all multiples of ten

MeasurementMeasurement

►LengthLength SI unit is the meter (m)SI unit is the meter (m) Divided into 100 equal parts called the Divided into 100 equal parts called the

centimeter (cm) centimeter (cm) One cm would be 1/100 of 1mOne cm would be 1/100 of 1m One millimeter (mm) is 1/10 of 1cmOne millimeter (mm) is 1/10 of 1cm One kilometer = 1000 mOne kilometer = 1000 m

►MassMass The amount of matter in an objectThe amount of matter in an object The mass is ALWAYS the same no matter The mass is ALWAYS the same no matter

where the object is in the Universewhere the object is in the Universe SI unit is the kilogram (kg)SI unit is the kilogram (kg) (how many grams?)(how many grams?)

►WeightWeight Measure of the gravitational force on an Measure of the gravitational force on an

objectobject Weight will vary (weight on moon is 1/6Weight will vary (weight on moon is 1/6thth

of Earth)of Earth) The SI unit is the Newton (n)The SI unit is the Newton (n)

►Area Area Require a combination of SI unitsRequire a combination of SI units Area is the amount of surface included Area is the amount of surface included

within a set of boundaries (length x width)within a set of boundaries (length x width) Area uses the square units of length mArea uses the square units of length m22

►VolumeVolume Volume is the amount of space occupied Volume is the amount of space occupied

by an objectby an object The unit of volume is the cubic meter mThe unit of volume is the cubic meter m33

Fluids use milliliter (mL) or liters (L)Fluids use milliliter (mL) or liters (L) 1 cm1 cm33 = 1 mL = 1 mL

►DensityDensity The amount of matter that occupies a The amount of matter that occupies a

given spacegiven space Found by dividing the mass by its volumeFound by dividing the mass by its volume Expressed by:Expressed by:

► Grams per cubic centimeter (g/cmGrams per cubic centimeter (g/cm33) ) ►Grams per milliliter (g/mL)Grams per milliliter (g/mL)►Kilograms per cubic meter (kg/mKilograms per cubic meter (kg/m33))

►TimeTime Interval between two eventsInterval between two events SI unit is the secondSI unit is the second

►TemperatureTemperature Measure of the average kinetic energy of Measure of the average kinetic energy of

the particles in a materialthe particles in a material Particles that vibrate quickly have higher Particles that vibrate quickly have higher

temperaturestemperatures Scientists often uses Celsius (C) Scientists often uses Celsius (C)

►Water freezes at 0C and boils at 100CWater freezes at 0C and boils at 100C►Conversion to F = multiply by 1.8 and add 32Conversion to F = multiply by 1.8 and add 32

►Temperature Contd.Temperature Contd. SI unit for temperature is Kelvin (K)SI unit for temperature is Kelvin (K) The coldest possible temperature is The coldest possible temperature is

absolute zero = 0K or -273Cabsolute zero = 0K or -273C The difference is to simply subtract 273 The difference is to simply subtract 273

from the K temperature to get the Celsius from the K temperature to get the Celsius temperaturetemperature

►More practiceMore practice Conversion of F to C -->Conversion of F to C -->

►(F-32) x 5/9 or (F-32) /1.8(F-32) x 5/9 or (F-32) /1.8

Scientific NotationScientific Notation

►Some numbers are too small or too Some numbers are too small or too large to write outlarge to write out

►Scientific notation allows the number Scientific notation allows the number to be expressed as a value between 1 to be expressed as a value between 1 and 10 multiplied by a power of 10and 10 multiplied by a power of 10

►The power of 10 tells you the number The power of 10 tells you the number of places the decimal point must be of places the decimal point must be shifted so that only one digit remains shifted so that only one digit remains to the left of the decimal pointto the left of the decimal point

► If the decimal point is to be shifted to the If the decimal point is to be shifted to the left, then the exponent of 10 is positive left, then the exponent of 10 is positive

►Examples:Examples: The number of grains of sand on Earth = The number of grains of sand on Earth =

4,000,000,000,000,000,000,000.00 4,000,000,000,000,000,000,000.00 Can Can be written as 4 x 10be written as 4 x 102121

EarthEarth’’s mass is s mass is 5,974,200,000,000,000,000,000,000 5,974,200,000,000,000,000,000,000 Can Can be written as 5.9742 x 10be written as 5.9742 x 1024 24

► If the decimal must be shifted toward If the decimal must be shifted toward the right, then the exponent will be the right, then the exponent will be negativenegative

►Example:Example: The diameter of an atom is 0.0000000001 The diameter of an atom is 0.0000000001

m m Can be written as 1 x 10 Can be written as 1 x 10-10-10