1. Chapter 2 Data Analysis Section 2.1 Units of Measurement

2. Metric System Units for scientific measurements Developed in France in 18 th 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-

6. Prefixes

7. 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

8. Temperature Hotness/coldness Direction of heat flow Celsius and Kelvin

9. 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

10. Fahrenheit to Celsius  F = (9/5) (  C) + 32  C = (5/9) (  F + 32)

11. Kelvin Scale SI temperature scale Based on the properties of gases Zero is the lowest obtainable temperature Absolute Zero 0 K = -273.15  C

12. Kelvin to Celsius K =  C + 273.15

13. Derived Units Unit derived from a combination of base units Examples: Volume and Density

14. Volume Derived SI Unit Cubic meters (m 3 ) Cubic centimeters (cm 3 ) used in chemistry cc 1 milliliter = 1 cubic centimeter »1 mL = 1 cm 3

15. Density Density = Mass/Volume Derived SI Unit –g/cm 3 –g/mL Always specify temperature when reporting density!! If no specification, assume 25  C