Conversions & Dimensional Analysis

1. Conversions & Dimensional Analysis Chapter 2 section 2 in textbook

2. SI Base Units Page 34 in textbook

3. Prefixes Page 35 in book

4. Prefixes Kilo 1000 units Hecto 100 units Deka 10 units Deci 0.1 unit Centi 0.01 unit Milli 0.001 unit Meters Liters Grams 4km = _______m How many jumps does it take? 1st - Determine your starting point 2nd - Count the jumps to your ending point 3rd - move the decimal the same number of jumps in the same direction

5. Dimensional Analysis • Dimensional Analysis:is going from one unit to another. • Have you ever converted inches into feet or years into days? • If so, then you have done dimensional analysis

6. Dimensional Analysis • Dimensional Analysis– method of problem-solving that focuses on changing units • Conversion Factor– ratio of equal values used to go from one unit to another • Example: 1 foot = 12 inches • Can be written as 1 foot 12 inches

7. Rules for Dimensional Analysis • ALWAYS start with what is given!!! • Draw a multiplicationsign and a line • Place the unit to be canceled on the bottom • Place a conversion factoron the line you have drawn • Cross out units and see what you have left. • You must have one on top& one on the bottom A x B A / /

8. Let’s try an example… Let’ s convert 32.5 inches to feet.

9. Try this example… • How many seconds are in 82.95 minutes?

10. What if you need to Change 2 Units? Convert 65 miles per hour to kilometers per second (0.625 miles = 1 Km)

11. Conversions with Prefixes • Conversions with prefixes are done in exactly the same manner • You just have to know the prefixes

12. Rules with Prefixes • The rules are the same… • Start with the what is given • Place the cross out unit on the bottom • Place conversion unit on top • Keep crossing out until you get what you want

13. Let’s try one • Convert 5.712 g to mg

14. Try this one… • Convert 785 mm to km

15. Temperature Conversions • The three units for measuring temperature are… • Fahrenheit – United States • Celsius • Kelvin Celsius: Freezing point of water = 0°C Boiling Point =100°C Kelvin: Freezing point of water = 273K Boiling Point =373K

16. To Convert Among Temperatures Use These Formulas • ºF = 1.8 ºC + 32 • ºC = 0.56 (ºF – 32) • K = ºC + 273.15

17. Try these examples • Convert 35 °C to Kelvin

18. Example • Convert 55 ºC to ºF

19. Example • Convert 95.8 ºF to ºC

20. Example • Convert 75.0 °F to Kelvin