Chapter 2 Data Analysis

1
Chapter 2Data Analysis

• Section 2.1
• Units of Measurement

2
Metric System

• Units for scientific measurements
• Developed in France in 18th century
• Unlike English system

3
SI Units

• International agreement
• Updated metric system
• 7 Base Units

4
Base Units

• Measurements based on an object or event in the
  physical world
• Independent of other units

5
Prefixes

• Decimal fractions
• Multiples of various units
• Ex milli-

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Prefixes
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Length and Mass

• Length SI Unit ? meter (m)
• 1 meter 1.0936133 yd
• Mass SI Unit ? kilogram (kg)
• 1 kg 2.2 lbs
• Unusual use of prefix

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Temperature

• Hotness/coldness
• Direction of heat flow
• Celsius and Kelvin

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Celsius Scale

• Everyday scale in most countries
• Used often in scientific studies
• 0? C Freezing point of water
• 100? C Boiling point of water at sea level

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Fahrenheit to Celsius

• ?F (9/5) (?C) 32
• ?C (5/9) (?F 32)

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Kelvin Scale

• SI temperature scale
• Based on the properties of gases
• Zero is the lowest obtainable temperature
• Absolute Zero
• 0 K -273.15 ?C

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Kelvin to Celsius

• K ?C 273.15

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Derived Units

• Unit derived from a combination of base units
• Examples Volume and Density

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Volume

• Derived SI Unit
• Cubic meters (m3)
• Cubic centimeters (cm3) used in chemistry
• cc
• 1 milliliter 1 cubic centimeter
• 1 mL 1 cm3

15
Density

• Density Mass/Volume
• Derived SI Unit
• g/cm3
• g/mL
• Always specify temperature when reporting
  density!! If no specification, assume 25?C