1. Le Système International d'Unités (International system of units)
The SI Metric System
Modern form of the metric system
The world's most widely used system of measurement
The standards, published in 1960 are the result of an initiative started in 1948
The SI has been declared to be an evolving system; thus prefixes and units are created and unit definitions are modified through international agreement as the technology of measurement progresses and the precision of measurements improves. 
The 25th General Conference on Weights and Measures (CGPM) meeting in the final quarter of 2014 considered a proposal to change the definitions of some base units, particularly the kilogram. (meets in Sèvres (south-west of Paris) every four to six years)
Le Système International d'Unités
(International system of units)

2. Metric System Created standard system of measurement
Decimal system (base of 10)
Uses decimal-based prefixes to denote multiples & sub-multiples of base units
General Conference on Weights and Measures (CGPM) – est. 1875
The General Conference on Weights and Measures (French: Conférence générale des poids et mesures - CGPM) is the senior of the three Inter-governmental organizations established in 1875 under the terms of the Metre Convention (French: Convention du Mètre) to represent the interests of member states. The treaty, which also set up two further bodies, the International Committee for Weights and Measures (French: Comité international des poids et mesures- CIPM) and the International Bureau of Weights and Measures (French: Bureau international des poids et mesures - BIPM), was drawn up to coordinate international metrology and to coordinate the development of the metric system.
The conference meets in Sèvres (south-west of Paris) every four to six years. Initially it was only concerned with the kilogram and the metre, but in 1921 the scope of the treaty was extended to accommodate all physical measurements and hence all aspects of the metric system. In 1960 the 11th CGPM approved the Système International d'Unités, usually known as "SI".
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3. History France (1790s) Germany (1830s) Britain (1900) CGPM (1954)
Length & Mass – meter, kilogram
Germany (1830s)
Time – second
Britain (1900)
Electrical – ampere
CGPM (1954)
Temperature & Luminance – Kelvin, candela
CGPM (1971)
Quantity of matter - mole
The metric system was first implemented during the French Revolution (1790s) with just the metre and kilogram as standards of length and mass[Note 1] respectively. In the 1830s Carl Friedrich Gauss laid the foundations for a coherent system based on length, mass and time. In the 1860s a group working under the auspices of the British Association for the Advancement of Science formulated the requirement for a coherent system of units with base units and derived units. The inclusion of electrical units into the system was hampered by the customary use of more than one set of units, until 1900 when Giovanni Giorgi identified the need to define one single electrical quantity as a fourth base quantity alongside the original three base quantities.
Meanwhile, in 1875, the Treaty of the Metre passed responsibility for verification of the kilogram and metre against agreed prototypes from French to international control. In 1921 the Treaty was extended to include all physical quantities including electrical units originally defined in 1893.
In 1948 an overhaul of the metric system was set in motion which resulted in the development of the "Practical system of units" which, on its publication in 1960, was given the name "The International System of Units". In 1954 the 10th General Conference on Weights and Measures (CGPM) identified electric current as the fourth base quantity in the practical system of units and added two more base quantities—temperature and luminous intensity—making six base quantities in all. The units associated with these quantities were the metre, kilogram, second, ampere, Kelvin and candela. In 1971 a seventh base quantity, amount of substance represented by the mole, was added to the definition of SI.
The meter was the basis for the entire metric system. If you form a cube with edges measuring 1/10th of a meter (1 decimeter or 10 cm) then fill it with water you have the volume measurement for one liter. If you then weigh that liter of water you have the weight measurement for one kilogram . Pretty nifty.
Image source: mined from Google images

4. CGPM Meetings

5. CGPM Meetings

6. CGPM Meetings

7. CGPM Meetings

8. CGPM Meetings

9. CGPM Meetings

10. International System (SI)
Published by CGPM in 1960
Adopted as a standard system of measurement throughout the world in 1960s
Continues to evolve – regular meetings every 4 to 6 years
Most recent proposal – change the definition of the kilogram base unit

11. Anti-Metric System Hold outs…
U.S.A.
Liberia
Myanmar (formerly Burma)
(2013 article)
More on the topic:
Stuff You Should Know Podcast: “Why isn’t the U.S. on the metric system?” -

12. Seven Base Units Meter Mole Kilogram Ampere Second Candela Kelvin
RadioLab Blog Article: “The Meter: The Measure of a Man” -
RadioLab Podcast Episode: “Weights and Measures” -
RadioLab Podcast Episode: “Less than or equal to Kg” -
Let’s look at the origins for each measurement in your lab manual (p. 27?)…

13. Current Definitions of Base Units
Meter (m) - The distance travelled by light in vacuum in 1/  second.
Kilogram (kg) - There is a standard platinum/iridium 1 kg mass housed near Paris at the International Bureau of Weights and Measures (BIPM).
Second (s) - the duration of periods of the radiation corresponding to the transition between the two hyperfine levels of the cesium-133 atomic ground state.
Kelvin (K) - the fraction 1/ of the thermodynamic temperature of the triple point of water.

14. Current Definitions of Base Units
Ampere (A) - that constant current which, if maintained in two infinitely long straight parallel conductors which have negligible circular cross- section, and placed 1 m apart in vacuum, would produce between a force between the conductors equal to 2 x 10-7newton per meter of length.
Mole (mol) -  the amount of a substance which contains as many entities as there are atoms in kilograms of carbon-12.
Candela (cd) - luminous intensity, in a given direction, of a source emitting monochromatic radiation of frequency 540 x 1012 hertz with radiant intensity in that direction of 1/683 watt per steradian.

15. System of Prefixes
In the lab manual

16. Using Prefixes - Meter 1 micrometer (µm) = 0.000001 meter
1 millimeter (mm) = meter
1 centimeter (cm) = 0.01 meter
1 decimeter (dm) = 0.1 meter
1 dekameter (dkm) = 10 meters
1 hectometer (hm) = 100 meters
1 kilometer (km) = 1000 meters

17. Conversion Factors
In the lab manual

18. Recording Measurements
The Scientific Way

19. Precision vs Accuracy Precision Accuracy Reproducibility
Check by repeated measurements
Poor precision results from poor techniques
Accuracy
Correctness
Check by using a different method
Poor accuracy results from procedural or equipment flaws

20. Precision vs Accuracy

21. Significant Figures
“Sig-figs”
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22. Sig-Figs Merriam-Webster: Significant (adj.): having meaning
Significant figures of a number are those digits that carry meaning contributing to the number’s accuracy, and thus the reliability of the data being collected.

23. Sig-Figs
The precision of an instrument reflects the number of significant figures in a reading
Micro-balance versus bathroom scale
The number of significant figures in a lab measurement is the number of digits that are known accurately, plus one that is uncertain or doubtful.
This concept makes the assumption that there is an error of ±1 in the final recorded decimal digit.
For example, when you record the number 87.1, the sig-figs rule assumes that that you meant 87.1 ±0.1; however, if you recorded 87.10, the sig-figs rule would assume that you meant 87.1 ± So, that last zero illustrated that your data was ten times more accurate than would have been assumed had you not recorded it.
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24. Rules of Sig-Figs
In the lab manual

25. Rules of Sig-Figs
In the lab manual

26. Sig-Figs: Cardinal Rule of Calculation
A final result or calculation should never contain any more significant figures than the least precise data used to calculate it.
Measurement #1 = cm
Measurement #2 = cm
Calculator: × 1.62 = cm2
Report: cm2

27. Sig-Figs: General Rule of Calculation
The concept applies only to measured quantities.
For example, numbers that are standard (known) quantities are assumed to have an infinite number of sig-figs.
“There are 100 centimeters in a meter”:
….etc. centimeters
….etc. meters

28. Sig-Figs: Adding & Subtracting
Use least number of decimal places:
Calculator: =
Sig-fig Rule: = (one decimal place)
Calculator: – 1.39 =
Sig-fig Rule: = (two decimal places)
Adding & Subtracting – When adding or subtracting numbers, your final answer can only have as many decimal places as the fewest number of decimal places in the original numbers.
Example 1: = → Significant Figures = 537.7
Example 2: – 1.39 = → Significant Figures =

29. Sig-Figs: Multiplying & Dividing
Use least number of sig-figs:
Calculator: × 3.2 =
Sig-fig Rule: = 49 (two sig-figs)
Calculator: ÷ =
Sig-fig Rule: = (three sig-figs)
Adding & Subtracting – When adding or subtracting numbers, your final answer can only have as many decimal places as the fewest number of decimal places in the original numbers.
Example 1: = → Significant Figures = 537.7
Example 2: – 1.39 = → Significant Figures =

30. Rounding
If a calculation yields a result that would suggest more precision than the measurement from which it originated, rounding off to the proper number of significant figures is required.
In the lab manual

31. Scientific Notation
Base 10 system
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32. Scientific Notation
Must be written in the following format:
5.349 × 109
Only one number in the one’s place
Significant Figures
Base 10
Positive or negative exponent

33. Move the decimal…
Note:
No commas – use spaces instead
Zero written before the decimal place
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