Scientific Method and the Metric System The Scientific Method Scientific method: a logical approach to solving problems by observing and collecting data, formulating hypotheses, and formulating theories that are supported by data

Observing and Collecting Data Observing: the use of the senses to obtain information Qualitative-descriptive Quantitative-numerical System: a specific portion of matter in a given region of space that has been selected for study during an experiment or observation

Formulating Hypotheses Hypothesis: A testable statement Serves as a basis for making predictions and for carrying out further experiments Often “if-then” statements Logic

Testing Hypotheses Requires experimentation that provides data to support or refute a hypothesis or theory If the data does not support the predictions, then the generalizations on which the predictions were based must be discarded or modified

Theorizing When the data from experiments confirm the hypothesis, scientists use models to explain what they observed Model: in science is more than a physical object: it is often an explanation of how phenomena occur and how data or events are related. If a model successfully explains a phenomena, it may become part of theory Theory: broad generalizations that explains a body of facts or phenomena

Scientific Method is NOT… LINEAR!!! It IS….complicated and messy

Versions of the scientific method http://www.newenergytimes.com/v2/images/ScientificMethod.jpg http://opinionsandexpressions.files.wordpress.com/2008/09/20071210_scientificmethod.png

More versions of the scientific method Important! http://www.lewis.edu/steve/science/images/SMflowchart.jpeg http://www.google.com/imgres?imgurl=http://www.sciencebuddies.org/science-fair-projects/overview_scientific_method2.gif&imgrefurl=http://www.sciencebuddies.org/science-fair-projects/project_scientific_method.shtml&usg=__D_X7ZRgf5v_lAJbIgGY5yeJg-yo=&h=348&w=362&sz=16&hl=en&start=1&zoom=1&um=1&itbs=1&tbnid=0tCD1dZBQbnH_M:&tbnh=116&tbnw=121&prev=/images%3Fq%3Dscientific%2Bmethod%26um%3D1%26hl%3Den%26sa%3DX%26tbs%3Disch:1

Units of Measurement You are constantly measuring things (whether you realize it or not)- what units are you most familiar with?

A few ideas Height- feet/inches (5’8”) Temperature- F not Celsius Baking- 1 cup, 1 tablespoon, 1 teaspoon Drinks- 12 ounces (can of soda) Weight- pounds (???lbs) Distance- miles

SI Measurement SI- a single measurement system adopted in 1960 by the General Conference on Weights and Measurements Contains 7 base units and many derived

SI Base Units Quantity Quantity Symbol Unit name Unit abbreviation Length l meter m Mass kilogram kg Time t second s Temperature T kelvin Amount of substance n mole mol Electric current I ampere A Luminous Intensity Iv candela cd

Mass Mass- measure of the quantity of matter SI unit-kilogram Weight- measure of the gravitational pull on matter Mass does not depend on such as attraction Which is why your WEIGHT changes if you go to the moon (1/6 to be exact)

Mountain Dew Mass Demo Who drank a soda yesterday What was it? Did you notice the sugar content? What was the unit of measure in? Can you visualize how much sugar you are actually consuming in a 12oz of soda?

Length SI unit- meter United States-miles Everyone else-kilometers How tall are you in meters?! 1 foot = 0.3048 meters If you are 5’4” so in meters you are 1.6256m

Derived SI Units Derived units- combinations of SI base units Quantity Quantity Symbol Unit name Unit abbreviation Derivation Area A square meter m2 length x width Volume V cubic meter m3 length x width x height Density D kilograms per cubic meter kg/m3 mass/volume Molar mass M kilograms per mole kg/mol mass/amount of substance Concentration c moles per liter amount of substance/volume Molar Volume Vm cubic meters per mole m3/mol volume/amount of substance Energy E  Joule J force x length

Volume Volume: the amount of space occupied by an object SI unit-m3 Non-SI unit-Liters 1000mL=1L 1000cm3=1Liter 1L=1000mL=1000cm3

Density Always remember: I DENSITY!!!! Density=Mass/Volume

Density Density: the ratio of mass to volume or mass/volume SI derived units: mass (kg) and volume (cubic meter) kg/m3 Characteristic physical property of a substance Density varies with temperature; generally density decreases with increasing temperature

SI prefixes http://stpatschem11.files.wordpress.com/2009/09/600px-prefixes.png

Conversion Factors Conversion factor: a ratio from the equality between two different units that can be used to convert from one unit to the other How many minutes are in a day? 1440 minutes How did you do it?

Minutes in a day _____ minutes per day= 60 minutes/1 hour x 24 hours/ day Answer: 1440 minutes/day

Handy equation Quantity sought= quantity given x conversion factor

Derive conversion factors Derive conversion factors if you know the relationship between the unit you HAVE and the unit you WANT Example: Express a mass of 5.712 grams in milligrams and in kilograms Hint: 1gram=1000mg 1kg=1000 grams

Answer 5.712 grams x 1000mg/1gram=5712milgrams 5.712grams x 1 kg/1000grams =.005712kg

Practice makes perfect Complete the following conversions: 10.5g=____kg 1.57km=____m 1.2L=_____mL 358cm=_____m 3548.6mL=_____cm3

answers Complete the following conversions: 10.5g=.0105 kg 1.57km= 1570 m 1.2L=1200 mL 3548.6mL= 3548.6 cm3

Density problem The density of gold is 19.3g/cm3. What is the volume, in cm3, of a sample of gold with mass .715kg?

Answer 37.05cm3 ____cm3=.715kg x 1000g/1kg x 1cm3/19.3g