1. Scientific Measurement Qualitative vs. Quantitative Qualitative measurements give results in a descriptive nonnumeric form. (The result of a measurement is an _____________ describing the object.) *Examples: ___________, ___________, long, __________... Quantitative measurements give results in numeric form. (The results of a measurement contain a _____________.) *Examples: 4’6”, __________, 22 meters, __________... Accuracy vs. Precision Accuracy is how close a ___________ measurement is to the ________ __________ of whatever is being measured. Precision is how close ___________ measurements are to _________ ___________. adjective shortheavycold number 600 lbs.5 ºC single valuetrue several othereach

2. Practice Problem: Describe the shots for the targets. Bad Accuracy & Bad PrecisionGood Accuracy & Bad Precision Bad Accuracy & Good PrecisionGood Accuracy & Good Precision

3. The SI System (The Metric System) Here is a list of common units of measure used in science: Standard Metric Unit Quantity Measured kilogram, (gram) ______________ meter ______________ cubic meter, (liter) ______________ seconds ______________ Kelvin, (˚Celsius) ______________ The following are common approximations used to convert from our English system of units to the metric system: 1 m ≈ _________ 1 kg ≈ _______ 1 L ≈ 1.06 quarts 1.609 km ≈ 1 mile 1 gram ≈ _______________________ 1mL ≈ _____________ volume 1mm ≈ thickness of a ________ mass length volume time temperature 1 yard sugar cube’s 2.2 lbs. mass of a small paper clip dime

4. The SI System (The Metric System)

5. Metric Conversions The metric system prefixes are based on factors of _______. Here is a list of the common prefixes used in chemistry: kilo- hecto- deka- deci- centi- milli- The box in the middle represents the standard unit of measure such as grams, liters, or meters. Moving from one prefix to another involves a factor of 10. *Example: 1000 millimeters = 100 ______= 10 ______ = 1 ______ The prefixes are abbreviated as follows: k h da g, L, m d c m *Examples of measurements: 5 km 2 dL 27 dag 3 m 45 mm grams Liters meters 10 cmdmm

6. Metric Conversions To convert from one prefix to another, simply count how many places you move on the scale above, and that is the same # of places the decimal point will move in the same direction. Practice Problems: 380 km = ______________m 1.45 mm = _________m 461 mL = ____________dL 0.4 cg = ____________ dag 0.26 g =_____________ mg 230,000 m = _______km Other Metric Equivalents 1 mL = 1 cm 3 1 L = 1 dm 3 For water only: 1 L = 1 dm 3 = 1 kg of water or 1 mL = 1 cm 3 = 1 g of water Practice Problems: (1) How many liters of water are there in 300 cm 3 ? ___________ (2) How many kg of water are there in 500 dL? _____________ 380,000 4.61 260 0.00145 0.0004 230 0.3 L 50 kg kilo- hecto- deka- deci- centi- milli-

7. KILO 1000 Units HECTO 100 Units DEKA 10 Units DECI 0.1 Unit CENTI 0.01 Unit MILLI 0.001 Unit Meters Liters Grams Ladder Method How do you use the “ladder” method? 1 st – Determine your starting point. 2 nd – Count the “jumps” to your ending point. 3 rd – Move the decimal the same number of jumps in the same direction. 4 km = _________ m 1 2 3 How many jumps does it take? Starting Point Ending Point 4. 1 __. 2 3 = 4000 m

8. Try these conversions using the ladder method. 1000 mg = _______ g 1 L = _______ mL160 cm = _______ mm 14 km = _______ m109 g = _______ kg 250 m = _______ km Conversion Practice Compare using, or =. 56 cm 6 m 7 g 698 mg

9. Write the correct abbreviation for each metric unit. 1) Kilogram _____ 4) Milliliter _____ 7) Kilometer _____ 2) Meter _____ 5) Millimeter _____ 8) Centimeter _____ 3) Gram _____ 6) Liter _____ 9) Milligram _____ Try these conversions, using the ladder method. 10) 2000 mg = _______ g 15) 5 L = _______ mL 20) 16 cm = _______ mm 11) 104 km = _______ m 16) 198 g = _______ kg 21) 2500 m = _______ km 12) 480 cm = _____ m 17) 75 mL = _____ L 22) 65 g = _____ mg 13) 5.6 kg = _____ g 18) 50 cm = _____ m 23) 6.3 cm = _____ mm 14) 8 mm = _____ cm 19) 5.6 m = _____ cm 24) 120 mg = _____ g Metric Conversion Challenge

10. Compare using, or =. 25) 63 cm 6 m 27) 5 g 508 mg 29) 1,500 mL 1.5 L 26) 536 cm 53.6 dm 28) 43 mg 5 g 30) 3.6 m 36 cm

11. 11

12. 12 The most common metric units of length are:  millimeter  centimeter  meter  kilometer

13. 13 Metric Units of Length  The basic unit of length in the metric system is the meter.  All of the other metric units of length are defined in terms of the meter.

14. 14 UnitSymbolMeaningModel

15. 15 UnitSymbolMeaningModel millimeter centimeter meter kilometer

16. 16 UnitSymbolMeaningModel millimetermm centimeter meter kilometer

17. 17 UnitSymbolMeaningModel millimetermm0.001 m centimeter meter kilometer

18. 18 UnitSymbolMeaningModel millimetermm0.001 mThickness of a dime centimeter meter kilometer

19. 19 UnitSymbolMeaningModel millimetermm0.001 mThickness of a dime centimetercm meter kilometer

20. 20 UnitSymbolMeaningModel millimetermm0.001 mThickness of a dime centimetercm0.01 m meter kilometer

21. 21 UnitSymbolMeaningModel millimetermm0.001 mThickness of a dime centimetercm0.01 mWidth of a large paperclip meter kilometer

22. 22 UnitSymbolMeaningModel millimetermm0.001 mThickness of a dime centimetercm0.01 mWidth of a large paperclip meterm kilometer

23. 23 UnitSymbolMeaningModel millimetermm0.001 mThickness of a dime centimetercm0.01 mWidth of a large paperclip meterm1 m kilometer

24. 24 UnitSymbolMeaningModel millimetermm0.001 mThickness of a dime centimetercm0.01 mWidth of a large paperclip meterm1 mWidth of a doorway kilometer

25. 25 UnitSymbolMeaningModel millimetermm0.001 mThickness of a dime centimetercm0.01 mWidth of a large paperclip meterm1 mWidth of a doorway kilometerkm

26. 26 UnitSymbolMeaningModel millimetermm0.001 mThickness of a dime centimetercm0.01 mWidth of a large paperclip meterm1 mWidth of a doorway kilometerkm1000 m

27. 27 UnitSymbolMeaningModel millimetermm0.001 mThickness of a dime centimetercm0.01 mWidth of a large paperclip meterm1 mWidth of a doorway kilometerkm1000 mAbout 2 ½ times around the track

28. 28 Metric Units of Length  1kilometer = 1000 meters  1meter = 100 centimeters  1centimeter = 10 millimeters  1meter = 1000 millimeters

29. 29 Which metric unit of length would be the most appropriate to measure: the distance between cities? km the length of an ant? mm the length of your math book? cm the length of the hallway? m the height of a giraffe? m

30. 30 Metric Units of Length  To change from a large unit to a small unit - multiply Measurement Conversion  To change from a small unit to a large unit - divide

31. Metric Volume: Cubic Meter (m 3 ) 10 cm x 10 cm x 10 cm = Liter

32. grams Liters meters Area and Volume Conversions If you see an exponent in the unit, that means when converting you will move the decimal point that many times more on the metric conversion scale. *Examples: cm 2 to m 2......move ___________ as many places m 3 to km 3......move _____ times as many places Practice Problems: 380 km 2 = _________________m 2 4.61 mm 3 = _______________cm 3 k h da g, L, m d c m twice 3 380,000,000 0.00461

33. Mass vs. Weight Mass depends on the amount of ___________ in the object. Weight depends on the force of ____________ acting on the object. ______________ may change as you move from one location to another; ____________ will not. You have the same ____________ on the moon as on the earth, but you ___________ less since there is less _________ on the moon. matter gravity Weight mass gravity weigh Mass = 80 kg Weight = 176 lbs. Mass = 80 kg Weight = 29 lbs.

34. Density Density is a ___________ of an object’s mass and its volume. Density does not depend on the _________ of the sample you have. The density of an object will determine if it will float or sink in another phase. If an object floats, it is _______ dense than the other substance. If it sinks, it is ________ dense. The density of water is 1.0 g/mL, and air has a density of 0.00129 g/mL (or 1.29 g/L). Density = Mass/Volume Mass = D x V ratio size less more Density = m/V Volume = m/D

35. Density Practice Problems: (1) The density of gold is 19.3 g/cm 3. How much would the mass of a bar of gold be? Assume a bar of gold has the following dimensions: L= 27 cm W= 9.0 cm H= 5.5 cm (2) Which picture shows the block’s position when placed in salt water? (3) Will the following object float in water? _______ Object’s mass = 27 g Object’s volume= 25 mL Volume = L x W x H Volume = 27 x 9.0 x 5.5 = 1336.5 cm 3 mass = D x V mass = 19.3 g/cm 3 x 1336.5 cm 3 = 25,794.45 g mass ≈ 26,000 g = 26 kg ≈ 57 lbs. No! It will sink. (D > 1)

36. Measuring Temperature Temperature is the ____________ or ____________ of an object. The Celsius temperature scale is based on the freezing point and boiling point of __________. F.P.= 0˚CB.P.= 100˚C The Kelvin temperature scale, sometimes called the “absolute temp. scale”, is based on the ____________ temperature possible, absolute zero. (All molecular motion would __________.) Absolute Zero = 0˚ Kelvin = −273˚ C To convert from one temp. scale to another: ˚C = Kelvin − 273 K= Celsius + 273 Practice Problems: Convert the following 25˚C = _______ K 473 K = _______˚C hotnesscoldness water lowest stop 298 200 (25 + 273) (473 – 273)

37. Temperature Scales Liquid Nitrogen

38. Evaluating the Accuracy of a Measurement The “Percent Error ” of a measurement is a way of representing the accuracy of the value. (Remember what accuracy tells us?) % Error = (Accepted Value) − (Experimentally Measured Value) x 100 (Accepted Value) Practice Problem: A student measures the density of a block of aluminum to be approximately 2.96 g/mL. The value found in our textbook tells us that the density was supposed to be 2.70 g/mL. What is the accuracy of the student’s measurement? (Absolute Value) % Error = |2.70−2.96| ÷ 2.70 =0.096296…x 100 =9.63% error