1. 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

2. 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

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

4. 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

5. 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

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

7. Versions of the scientific method

8. More versions of the scientific method
Important!

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

10. 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

11. 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

12. 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

13. 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)

14. 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?

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

16. 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

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

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

19. 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

20. SI prefixes

21. 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?

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

23. Handy equation
Quantity sought= quantity given x conversion factor

24. 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 grams in milligrams and in kilograms
Hint:
1gram=1000mg
1kg=1000 grams

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

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

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

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

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