1. THE SCIENTIFIC METHOD A SYSTEMATIC APPROACH
A WAY OF ANSWERING QUESTIONS AND/OR SOLVING PROBLEMS
STEPS OF THE SCIENTIFIC METHOD
OBSERVATION
LEADS TO A QUESTION OR DISCOVERS A PROBLEM
RESEARCH (OBSERVATION, LIBRARY, OTHER)
HYPOTHESIS
A TENTATIVE ANSWER TO THE QUESTION
EXPERIMENT
SCRUPULOUS RECORD KEEPING
ANALYZE DATA
CONCLUSION
BASED ON THE EXPERIMENTAL DATA
REPEAT EXPERIMENTATION
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LABORATORY CHEMISTRY

2. THE SCIENTIFIC METHOD NATURAL LAW THEORY OBSERVATION QUESTION
(MODEL)
HYPOTHESIS
EXPERIMENT
THEORY
MODIFIED
AS NEEDED
PREDICTION
CONCLUSION
REPEAT (EXPERIMENT)
EXPERIMENT
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LABORATORY CHEMISTRY

3. THE SCIENTIFIC METHOD INTERPRETING RESULTS LAWS AND THEORIES
EXPERIMENTAL CONTROLS
A CONTROL RESPONDS IN A PREDICTABLE WAY TO THE EXPERIMENT.
LAWS AND THEORIES
NATURAL LAW
DRAWS TOGETHER MANY OBSERVATIONS AND THE RESULTS OF MANY EXPERIMENTS INTO A “BIG PICTURE”
DOES NOT EXPLAIN WHAT THE PICTURE MEANS
THEORY
PROVIDES EXPLANATION
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LABORATORY CHEMISTRY

4. THE SCIENTIFIC METHOD What is the scientific method?
List the steps of the scientific method.
What is a variable? An experimental control?
What is the difference between a natural law and a scientific theory?
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LABORATORY CHEMISTRY

5. UNITS OF MEASURE
THE INTERNATIONAL SYSTEM OF UNITS (SYSTEME INTERNATIONAL D’ UNITES)
BUILT ON A SET OF SEVEN METRIC UNITS WHICH ARE CALLED THE BASE UNITS OF THE SI
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LABORATORY CHEMISTRY

6. UNITS OF MEASURE SI BASE UNITS mass kilogram kg length meter m
PHYSICAL QUANTITY UNIT NAME SYMBOL
mass kilogram kg
length meter m
time second s
count, quantity mole mol
temperature kelvin K
electric current ampere A
luminous intensity candela cd
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LABORATORY CHEMISTRY

7. UNITS OF MEASURE DERIVED UNITS
IN ADDITION TO THE SEVEN BASE UNITS, OTHER SI UNITS CAN BE MADE FROM COMBINATIONS OF THE BASE UNITS. USUALLY A CALCULATED VALUE…NOT A MEASUREMENT !
LENGTH (m) x
WIDTH (m)
AREA (m2) =
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LABORATORY CHEMISTRY

8. UNITS OF MEASURE DERIVED UNITS USED IN SCIENCE area square meter m2
PHYSICAL QUANTITY UNIT NAME SYMBOL
area square meter m2
volume cubic meter m3
force newton N
pressure pascal Pa
energy joule J
power watt W
voltage volt V
frequency hertz Hz
electric charge coulomb C
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LABORATORY CHEMISTRY

9. UNITS OF MEASURE NON SI UNITS USED IN SCIENCE
IN ADDITION TO THE BASE AND DERIVED SI UNITS THERE ARE OTHER UNITS COMMONLY USED IN CHEMISTRY
THESE ARE NOT SI UNITS, HOWEVER THEY ARE REGULARLY USED IN THE STUDY OF CHEMISTRY
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LABORATORY CHEMISTRY

10. UNITS OF MEASURE NON-SI UNITS USED IN SCIENCE volume liter L
PHYSICAL QUANTITY UNIT NAME SYMBOL
volume liter L
pressure atmosphere atm
millimeters of mercury mmHg
temperature Celsius degree Co
energy calories cal
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LABORATORY CHEMISTRY

11. UNITS OF MEASURE METRIC PREFIXES
A METRIC PREFIX IS ATTACHED TO THE BASE UNIT, CREATING A MORE CONVENIENT, EASIER TO USE UNIT.
PREFIXES CAN MAKE THE NEW UNIT LARGER OR SMALLER THAN THE BASE UNIT
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LABORATORY CHEMISTRY

12. UNITS OF MEASURE COMMON PREFIXES
PREFIX ABBREVIATION VALUE SCI. NOTATION
Giga- G
mega- M
kilo- k
hecto- h
deka- D (Dk)
ROOT UNIT meter, liter, gram
deci- d
centi- c
milli- m
micro- 
nano- n
pico- p
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13. UNITS OF MEASURE What are the SI units for length, mass, and volume?
What is a metric prefix? What does the metric prefix centi- mean? The prefix deci- ?
What is the difference between mass and weight?
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LABORATORY CHEMISTRY

14. UNCERTAINTY IN MEASUREMENT
MAKING MEASUREMENTS
IN MAKING A MEASUREMENT, YOU WRITE DOWN ALL OF THE CERTAIN (OR EXACT) DIGITS THAT THE INSTRUMENT CAN GIVE AND ALSO ONE UNCERTAIN DIGIT YOU ESTIMATE.
MEASUREMENTS ARE UNCERTAIN FOR TWO REASONS:
1. MEASURING INSTRUMENTS ARE NEVER COMPLETELY FREE OF FLAWS.
2. MEASURING ALWAYS INVOLVES SOME ESTIMATION.
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LABORATORY CHEMISTRY

15. UNCERTAINTY IN MEASUREMENT
ESTIMATING WITH A SCALE
MINISCUS
23  1 30 30 25 25 20 20 15 15 10 10 5 5
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LABORATORY CHEMISTRY

16. UNCERTAINTY IN MEASUREMENT
RELIABILITY IN MEASUREMENT
THERE ARE TWO WAYS TO CHECK RELIABILITY
PRECISION: REPEAT THE MEASUREMENT SEVERAL TIMES….A RELIABLE MEASUREMENT WILL GIVE ABOUT THE SAME RESULT AGAIN AND AGAIN.
ACCURACY: THE SECOND WAY IS TO CHECK THE RESULTS AGAINST A STANDARD. A MEASUREMENT THAT IS ACCURATE IS ONE THAT IS CLOSE TO THE ACCEPTED STANDARD.
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17. UNCERTAINTY IN MEASUREMENT
PRECISE
BUT
NOT ACCURATE
NOT
PRECISE
NOR
ACCURATE
BOTH
PRECISE
AND
ACCURATE
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LABORATORY CHEMISTRY

18. UNCERTAINTY IN MEASUREMENT
Explain why measurements are always uncertain.
Describe two ways to check the reliability of a measurement.
How would you find the uncertain digit in a measurement using a digital display? Using a scale ?
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LABORATORY CHEMISTRY

19. WORKING WITH NUMBERS SCIENTIFIC NOTATION
CONVERTING NUMBERS TO SCIENTIFIC NOTATION
TO WRITE NUMBERS IN SCIENTIFIC NOTATION, THE PROPER EXPONENT CAN BE FOUND BY COUNTING HOW MANY TIMES THE DECIMAL POINT MUST BE MOVED TO BRING IT TO ITS FINAL POSITION SO THAT THE NUMBER IS BETWEEN 1 AND 10.
IF THE NUMBER IS LESS THAN 1 THE EXPONENT OF 10 IS NEGATIVE 10-X
IF THE NUMBER IS GREATER THAN 1 THE EXPONENT IS POSITIVE 10X
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LABORATORY CHEMISTRY

20. WORKING WITH NUMBERS 32,700 3.27 X 104 O.OOO341 3.41 X 10-4 45,500,000
2.34 X 10-5
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21. WORKING WITH NUMBERS 0.0000056 5.6 X 10-6 7,250 7.25 X 103 3.25 X 104
32,500
3.25 X 104
X 10-3
5.939
X 100
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LABORATORY CHEMISTRY

22. MEASURED VALUE - ACCEPTED VALUE
WORKING WITH NUMBERS
PERCENTS AND PERCENT ERROR
RATIOS
MEASURED VALUE - ACCEPTED VALUE
EXPERIMENTAL
THEORETICAL
100 X
THEORETICAL
ACCEPTED VALUE IF
ACCEPTED VALUE
ACCEPTED AMOUNT =
THEN
GIVEN VALUE
GIVEN AMOUNT
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LABORATORY CHEMISTRY

23. PROBLEM SOLVING CONVERSIONS CONVERTING WITHIN THE SI SYSTEM
CONVERSIONS IN THE SAME DIMENSION
USING LINEAR, SQUARE, AND CUBIC MEASUREMENTS
CONVERSIONS IN DIFFERENT DIMENSIONS
CHANGING CUBIC, MASS AND VOLUME MEASUREMENTS
USING WATER
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LABORATORY CHEMISTRY

24. PROBLEM SOLVING: Conversions
Convert 234 mL into L.
Step 1
Kilo
Hecto
Deka
Standard (m, L,g)
deci
centi
milli
You want to go to Liters
That’s
three
steps 3 2
You are at milli- 1
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LABORATORY CHEMISTRY