1. Units of Measurement : SI unit and derived units Unit prefixes Unit conversion using dimensional analysis Scientific notation Increment, Accuracy, Precision MEASUREMENT

2. Distinguish between a number and a quantity. Name SI units for length, mass, time, temperature, volume and density. Define and identify base units; unit conversions; identify prefixes Perform unit conversion using dimensional analysis. OBJECTIVES

3. Units of Measurement In our daily lives we deal with making measurements routinely. –i.e., How much gasoline is required to fill your gas tank? What time did you wake up this morning? How fast did you drive to school today ? Doctors, nurses, pharmacists- –Doctors and nurses make measurements constantly. Measurements like pulse rate, blood pressure, temperature, drug dosage. Math - The language of Science –Scientists make countless measurements during their experiments to prove or disprove a theory.

4. Units of Measurement What is your response if I told you that: I weigh 65 In any measurement magnitude (the number) as well as the unit (meaning) must be stated. Otherwise, it is meaningless!

5. Number vs. Quantity Quantity : number + unit UNITS MATTER!!

6. Systems of Measurement Scientific Community The Rest of the World America English System 1 ft = 12 in 1 yd= 3 ft 1 mi. = 1,760 Yd 1 mi = 5280 ft Metric System 1 km = 1000 m 1 m = 100 cm Le System International d’Unites Le System International d’Unites What units are used? SI Units are basically an updated form of the metric system.

7. Metric system and the Le Systeme International d'Unites (SI) The Metric system is convenient because it uses only one fundamental unit for each type of measurement. For example for: *Length we use only meter, in the US we use foot, yard, inch. *Mass we use Kg not pound. All the Prefixes are multiples of 10.

8. SI Units QuantityBase UnitAbbrev. Length Mass Time Temp meter kilogram second kelvin m kg s K Amount of particles mole mol Symbol l m t T n

9. SI Prefix Conversions Giga Mega- G10 9 deci-d10 -1 centi-? milli-m10 -3 PrefixSymbolFactor micro-  10 -6 BASE UNIT---1 kilo-k10 3 Hecto-h10 2 Deka-da10 10 6

10. Derived Units: Combination of base units Area ( m 2 ) length  length = m x m Volume (m 3 ) –length  length  length= m x m x m D = MVMV Density (g/cm 3 ) –mass per volume

12. Temperature A measure of how hot or how cold an object is. SI Unit: the kelvin ( K ) Note: not a degree Absolute Zero= 0 K

13. Temperature Scales

14. Celsius and Kelvin K= o C + 273

15. Density An object has a volume of 825 cm 3 and a density of 13.6 g/cm 3. Find its mass. GIVEN: V = 825 cm 3 D = 13.6 g/cm 3 M = ? WORK : M = DV M = (13.6 g/cm 3 )(825cm 3 ) M = 11,200 g

16. Density A liquid has a density of 0.87 g/mL. What volume is occupied by 25 g of the liquid? GIVEN: D = 0.87 g/mL V = ? M = 25 g WORK : V = M D V = 25 g 0.87 g/mL V = 29 mL

17. Unit conversion using dimensional analysis Page Unit 1 - MEASUREMENT

18. SI Prefix Conversions 1.Find the difference between the exponents of the two prefixes. 2.Move the decimal that many places. To the left or right?

19. SI Prefix Conversions move left move right Giga Mega- G10 9 deci-d10 -1 centi-? milli-m10 -3 PrefixSymbolFactor micro-  10 -6 BASE UNIT---1 kilo-k10 3 Hecto-H10 2 Deca-D10 10 6

20. SI Prefix Conversions 1) 20 cm = ___________ m 2) 0.032 L = ______________ mL 3) 45 m = ______________ cm 4) 80.5 km = ______________ m

21. How would you convert 2h 45 min to second Convert 55.00 km/h to m/s

22. Steps: 1.Identify starting ( also called given, old )& ending ( target, new) units. 2. Line up conversion factors so units cancel.( hint : the new units should on the top) 3. Multiply all top numbers & divide by each bottom number. ( ) 4. Check units & answer. Converting by using Dimensional Analysis

23. Identify 10.0 in We start by writing down the Given (old) and its Unit Converting by using Dimensional Analysis: inch to cm

24. Line up 10.0 in x 1 in 2.54 cm We know 1 in = 2.54 cm. So our conversion factor is : 1 in = 2.54 cm. Since we want to convert to cm, it goes on the top. ( Hint) Converting by using Dimensional Analysis: inch to cm

25. Cancel units 10.0 in x 1 in 2.54 cm Now we cancel and collect units. The inches cancel out, leaving us with cm : the Target unit. Converting by using Dimensional Analysis: inch to cm

26. 10.0 in x 1 in 2.54 cm = 25.4 cm Since the unit is correct, all is left to do the math... The Answer Converting by using Dimensional Analysis: inch to cm

27. Lets check it out !!!!!! Find the 10 in mark and directly across at the cm side. What number do you find?

28. 5)You go to Europe and decide to have a haircut. Your hairdresser wants to cut your hair 8.0 cm shorter. How many inches will he be cutting off? Identify, line up, cancel out, multiply, check 8.0 cm1 in 2.54 cm = ? in Question: Is the conversion Factor the same? What’s the difference? Converting by using Dimensional Analysis: inch to cm

29. Convert 250 g into Kg Identify, line up, cancel out, multiply, check 250 g x 1Kg= Kg 1000 g Converting by using Dimensional Analysis: g to Kg

30. Convert 1.5 Kg into g Identify : Given and Target unit Line up: Conversion Factor 1.5 kg x = g Converting by using Dimensional Analysis: Kg to g Q: Which conversion factor will you be using? 1Kg = 1000g or 1000g= 1Kg

31. A more complex conversion km to m hr s kilometers into meters and hour into second. We can do both conversions at once using the same method as in the previous conversion.

32. Identify 80 km hr A more complex conversion km to m hr s Write down the _____and ____

33. Line up 80 km x hr 1 hr 3600 s A more complex conversion km to m hr s First conversion factor is: 1 hour = 3600 sec.

34. Line up 80 km x hr 1 hr x 3600 s 1000 m 1 km A more complex conversion km to m hr s The second conversion factor is: 1 km = 1000 m.

35. Cancel out units 80 km x hr 1 hr x 3600 s 1000 m 1 km = A more complex conversion km to m hr s Check your units !!! If you have chosen the correct conversion factors, you should only be left with the units you want to convert to. m s

36. 80 km x hr 1 hr x 3600 s 1000 m 1 km = 80,000 m 3600 s = m s A more complex conversion km to m hr s The Answer!!

37. Problem1:Convert 1 year into seconds yearseconds A Very more complex conversion to finish at home today !! 1 y 365 days 24h 1day 1 h 60s 1y = s

38. Problem2: Taft football needs 550 cm for a 1st down. How many yards is this? 550 cm 1 in 2.54 cm = yd cmyd 12in 1ft 1 yd 3 ft Dimensional Analysis

39. Problem3: A piece of wire is 1.3 m long. How many 1.5-cm pieces can be cut from this wire? 1.3 m = pieces cmpieces Dimensional Analysis

40. Problem5:How old are you in minutes? Age in y = min

41. Units and Conversions HW Due: tomorrow Homework How would you convert 2h 45 min to second Convert 55.00 km/h to m/s

42. Scientific Notation M x 10 n M is the coefficient 1<M<10 10 is the base n is the exponent or power of 10

43. Other Examples: 5.45E+6 5.45 x 10^6

44. Numbers less than 1 will have a negative exponent. Numbers bigger than 1 will have a positive exponent. A millionth of a second is: 0.000001 sec 1.0E-6 1.0x10^-6

45. Limits of Measurement Accuracy and Precision

46. Accuracy - a measure of how close a measurement is to the true value of the quantity being measured.

47. Example: Accuracy Who is more accurate (Susan or Amy) when measuring a book that has a true length of 17.0cm? Susan: 18.1cm, 16.0cm, 18.0cm, 17.1cm Amy: 16.5cm, 16.0cm, 16.2cm, 16.3cm

48. Precision – a measure of how close a series of measurements are to one another. A measure of how exact a measurement is regardless is it is close to the real value.

49. Example: Precision Who is more precise when measuring the same 17.0cm book? Susan: 17.0cm, 16.0cm, 18.0cm, 15.0cm Amy: 15.5cm, 15.0cm, 15.2cm, 15.3cm

50. Example: Evaluate whether the following are precise, accurate or both. Accurate Not Precise Not Accurate Precise Accurate Precise

51. Graduated Cylinder - Meniscus