1. Significant Figures, Scientific Notation, Unit Conversion, and Unit Magnitudes

2. Unit Conversion
SI units: The International System of Units (abbreviated SI from the French Système international d'unités]) is the modern form of the metric system
a system of units of measurement devised around seven base units and the convenience of the number ten

3. How to convert 1). Find your decimal point 2). Find your direction
3). Count your steps
4). Move the decimal

4. Kilo Hecto Deca base Deci Centi Milli
King Henry died by drinking chocolate milk
Example: 12 Kilograms = _____ Decigrams
Deci is 4 spaces to the left of Kilo so move the decimal 4 spaces to the right.
Answer: 12 kg = g

5. Unit Conversion
I will give you these conversion factors if you need them in a problem!
1 inch = 2.54 cm
exactly 1 lb = 454 g
1 qt = L
1 mi = 5280 ft
1 qt = 2 pt
4qt = 1 gal
1 ounce = grams

6. Unit Conversions Convert 3598 grams into pounds.
(exactly 1 lb = 454 g )

7. ANS: lbs

8. Unit Conversions Convert 231 grams into ounces.
(1 ounce = grams)

9. ANS:8.15 ounces

10. Unit Conversions How many gallons are in 5.67 L?
(1 qt = L and 4qt = 1 gal)

11. ANS: 1.50

12. Extra Practice Practice on your own 1). 5 decimeters = mm
2). 14 hL = L
3). 245 kilograms= mg
4) mm= m

13. Scientific Notation
Scientific notation is simply a method for expressing, and working with, very large or very small numbers. 
-Numbers in scientific notation are made up of three parts: the coefficient, the base and the exponent.
-EX: 5.67 x103 is the scientific notation for 5670
-5.67 x 103 
coefficient base exponent

14. Scientific Notation
1. The coefficient must be greater than or equal to 1 and less than 10.
2. The base must be 10.
3. The exponent must show the number of decimal places that the decimal needs to be moved to change the number to standard notation.  A negative exponent means that the decimal is moved to the left when changing to standard notation.

15. Converting to Scientific Notation
Move decimal until there’s 1 digit to its left.
-Places moved = exponent.
Large # (>1)  positive exponent
Small # (<1)  negative exponent
EX: Put in scientific notation
Practice

16. Scientific Notation Adding and Subtracting
Be sure that the exponents are the same
Then add or subtract the decimal number as listed
Multiplication and Division
To multiply – multiply the first factors then add the exponents
To divide – divide the first factors then subtract the exponent of the divisor from the exponent of the dividend

17. Scientific Notation Practice
Write the following numbers in scientific notation mm
438,904 s
Complete the following addition and subtraction problems
6.23 x 106 kL x 107 kL
9.87 x 104 g – 6.2 x 103 g
Complete the following multiplication and division problems
(4.8 x 105 km) x (2.0 x 103 km)
(8.4 x 106 L) ÷ (2.0 x 103 L)

18. Dimensional Analysis Dimensional Analysis Conversion Factor
A tool often used in science for converting units within a measurement system
Conversion Factor
A numerical factor by which a quantity expressed in one system of units may be converted to another system

19. Dimensional Analysis The “Factor-Label” Method
Units, or “labels” are canceled, or “factored” out

20. Dimensional Analysis Steps: 1. Identify starting & ending units.
2. Line up conversion factors so units cancel.
3. Multiply all top numbers & divide by each bottom number.
4. Check units & answer.

21. Dimensional Analysis Practice
How many seconds are in 1.4 days?
Plan: days hr min seconds
1.4 days x 24 hr x 60 min x 60 sec =
1 day hr min
sec

22. Density Calculate density and use density to identify pure substances
Ratio of mass to volume
Directly proportional measure of how tightly matter is packed
Substances can be identified by comparing densities to known densities
density (D) = mass (m) / volume (V)
Expressed in g/mL
Density can be calculated by measuring the change in volume by a specifically measured mass

23. Density Practice
A 5-mL sample of water has a mass of 5 g. What is the density of water?
An object with a mass of 10 g raises the level of water in a graduated cylinder from 25.1 mL to 30.1 mL. What is the density of the object?
The density of aluminum is 2.7 g/mL. What is the volume of 8.1 g?

24. Accuracy and Precision
EQ: In what ways do proper techniques contribute to reliable results?

25. Accuracy & Precision
Distinguish between accuracy and precision in measurement
Accuracy – extent to which a measurement approaches the true value of a quantity
Agreement of a measurement with the accepted value of the quantity
Precision – degree of exactness or refinement of a measurement
How close a series of measurements are to one another.

26. France vs.  Italy
Italy converts all five penalty kicks to win championship

27. A 41-year-old New York man who underwent two operations – one to remove a blood clot from the left side of his brain, and another when doctors discovered the clot was on the right side of his brain. The mistake? The patient's brain scan had been hung up backwards for viewing in the operating room. 

28. 2005 Yr:
Att= Comp=305
%Pass Completion= 305/453 = 67.3 %

29. What if she is inaccurate?

30. Accuracy vs Precision

31. % Error Calculating percent error % error = theoretical – actual x 100
The accepted length of a steel pipe is 5-m. Calculate the percent error for each of these measurements
5.25 m
4.75 m
5.5 m

32. Sig Figs Rules recognizing significant figures
Non-zero numbers are always significant
Zeros between non-zero numbers are always significant
All final zeros to the right of the decimal place are significant
Zeros that act as placeholders are not significant. Convert quantities to scientific notation to remove placeholder zeros
Counting numbers and defined constants have an infinite number of significant figures

33. Sig Figs Rounding Rules
If the digit to the immediate right of the last significant figure is less than five, do not change the last significant figure
If the digit to the immediate right of the last significant figure is greater than five, round up the last significant figure
If the digit to the immediate right of the last significant figure is equal to five and is followed by a nonzero digit, round up the last significant figure if odd. If even, do not round up.

34. Sig Figs How many significant figures in the following measurements?
431,801 kg
10,235.0 mg cm cg
Write the above in scientific notation to four significant figures

35. Sig Figs Rules for using significant figures in calculations
Addition or Subtraction
The answer can have no more digits to the right of the decimal point than there are in the measurement with the smallest number of digits to the right of the decimal point m m
m = m = 2.21 X 101 m

36. Sig Figs Multiplication or Division
The answer can have no more significant figures than there are in the measurement with the smallest number of significant digits
Problem:
g/mL x 500. mL = g
 x 102g = 5.57 x 102g

37. Sig Figs
Round the answers to each of the following problems to the correct significant figures
7.31 x x 103
8.54 x 10-3 – 3.41 x 10-4
(2.4 x 102) x (3.26 x 104)
(1.024 x 102) ÷ (5.12 x 101)