1. 1.3 NOTES Scientific Measurement

2. Why is it important to standardized measurment?

3. What’s the problem? Really? What?

5. The Metric System SI Units- International system, used for continuity
Base units 7 base units

6. Derived units Units made up of two or more base units
Examples: volume (L x W x H, m3), area (L x W, m2), velocity (m/s), density (g/mL)

8. The formula can be rearranged to solve for any of the variables
Density
Relates mass and volume
Density = Mass D = M
Volume V
The formula can be rearranged to solve for any of the variables
Example 1: What is the volume of a sample that has a mass of 20 grams and a density of 4 g/mL?
Example 2: A piece of metal with a mass of 147 g is placed in a 50 mL graduated cylinder. The water level rises from 20 mL to 41 mL. What is the density of the metal

9. Significant Figures
Measurements are only as accurate and precise as the instrument that produced it
The number of significant figures in a measurement is an indication of accuracy. For example, if you measure the length of a room by pacing it, your measurement will have less accuracy than if you measure it with a steel measuring tape, and the measurements recorded will have different numbers of significant figures. When pacing, you might record the length as 7 meters, a measurement with one significant figure. Using the tape, you might record the measurement as 7.27 meters, accurate to 3 significant figures.

10. Rules of significant figures (sig figs):
All nonzero digits are significant g has 3 significant figures
Zeros:
Zeros between 2 nonzero digits are always significant. Zeros between 2 significant digits are significant. e.g. 505mm has 3 sig figs
Trailing zeros (those at the right end of a whole number) are significant only if there is a decimal after the zero or if there is a bar over the zero. E.g L, or 2000 kg
All zeros after a decimal are significant only if there is a nonzero digit somewhere to the left of the zero. e.g has 2 sig figs; has only 1 sig fig
Leading zeros (those that precede nonzero digits) are placeholders and are never significant. e.g has 1 sig fig
Exact numbers, such as the 60 and the 1 in the sentence “60 min = 1 hour” have an infinite number of significant digits. Counting numbers such as “1 atom” have infinite significance.
When numbers are in scientific notation, the only significant part is what comes before the x10. For example, 2.3 x 103 has 2 sig figs, and x has 5.

11. How many significant figures are present in the following numbers?
x 105
Method # L R

12. Rules of significant figures (sig figs):
Rounding
Always look to the number to the right of the last number you are keeping.
If the number to the right is from 0-4, the last number stays the same.
If the number to the right is from 5-9, the last number rounds up.
Examples:
Round the following to 3 significant figures: 
Round the following to 3 significant figures: 
Round the following to 4 significant figures: 

13. Rules of significant figures (sig figs):
Adding and subtracting
Round your final answer to the least number of decimal places present in the factors
Examples:

14. Rules of significant figures (sig figs):
Round your final answer to the least number of significant figures present in the factors
Examples:
49 / 7 = X 5 =
147 / 7.0 =

15. Scientific Notation 1524  .00043 
A method of taking very large numbers or very small numbers and making them manageable
To put numbers in scientific notation, move the decimal so that only one number is in front of the decimal, with all other numbers behind the number
Examples
1524  

16. Scientific Notation Adding and subtracting
The exponent must be the same for all numbers you are adding and subtracting
Add the decimal portion together and keep the exponent the same
Examples:
5.2 X X X 103
X X X 104

17. Scientific Notation Multiplication
Multiply the decimal portion together
Add the exponents
Examples:
(6 X 103) X (1 X 106) = (1.2 X 103) X (4.1 X 102) =
(1.2 X 10-2) X (4.1 X 10-4) =

18. Scientific Notation Division 8 X 106 9 X 103 4 X 104 3 X 10-3
Divide the decimal portion
Subtract the exponents
Examples:
8 X X 103
4 X X 10-3

19. Metric Prefixes Prefix Exponential Factor Meaning - Example Kilo 103
1 000m = 1 kilometer
Hecta
102
100m = 1 hectometer
Deka
101
10m = 1 decameter
Base Unit
100
1 meter = 1 meter
Deci
10-1
.1 meter = 1 decimeter
Centi
10-2
.01 meter = 1 centimeter
Milli
10-3
.001 meter = 1 millimeter

20. Prefixes are used to represent quantities that are larger or smaller than the base units

21. Metric Prefixes
When you convert between two units, move the decimal. When going from a small unit to a larger unit, your number should get smaller. When going from a large unit to a smaller unit, the number should get smaller.
King Henry Died By Drinking Chocolate Milk
Kilo Hecta Deka Base Deci Centi Milli

22. Metric Prefixes Examples: 2.44 cm  km 3.57 g  mg
14 dam  hm dL  kL