Middle School Measurement Precision Teacher Lesson Guide Presentation

Middle School Measurement & Precision Teacher Lesson Guide Presentation 1. Review Theory Measurements help us describe the world and everything in it. Measurements can describe length, volume, weight, time, temperature, and countless other properties. Standardized Unit System Metric system and the English system All content © 2012 FLATE. This material is based upon work supported by the National Science Foundation (NSF) under Grant No. 0802436. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF. 1

Middle School Measurement & Precision Teacher Lesson Guide Presentation Review Theory, Cont. Property Metric Units English Units Length Meters, kilometers Volume cubic centimeters cubic inches Fluid Volume Milliliter, liter Inch, foot, mile Quart, gallon Mass Milligram, Ounce, pound, ton kilogram Temperature degree Celsius (˚C) degree Fahrenheit (˚F) 2

Middle School Measurement & Precision Teacher Lesson Guide Presentation Review Theory, Cont. • Accuracy Degree of closeness of measurements results to the true value • Precision, reproducibility or repeatability The degree to which repeated measurements of a quantity under unchanged conditions show the same results 3

Middle School Measurement & Precision Teacher Lesson Guide Presentation Review Theory, Cont. Accuracy & Precision Examples High Accuracy - Low Precision High Precision - Low Accuracy True Value 4

Middle School Measurement & Precision Teacher Lesson Guide Presentation 1 a. Exercise How accurate & Precise are U? 5

Middle School Measurement & Precision Teacher Lesson Guide Presentation 1 b. Tolerance Interval / Margin Error Example: Let’s measure Flater using a ruler: Ruler’s precision: 1/16 (0. 063 un) Tolerance interval: 2. 25 ± 0. 063 un Hi, My name is Flater! 6

Middle School Measurement & Precision Teacher Lesson Guide Presentation Figure 1. Ruler 2 a. Measuring Tools & Their use Figure 2. Flexible measuring tape Figure 3. Caliper Figure 4. Long distance measuring tape 7

Middle School Measurement & Precision Teacher Lesson Guide Presentation Sample of Measuring Tools Cont. Graduated cylinder, measuring cup, water velocity-meter, thermometer, analytical balance 8

Middle School Measurement & Precision Teacher Lesson Guide Presentation Measuring Tools Calibration Measuring devices should be calibrated against standards Example: A set of metric gauge blocks 9

Middle School Measurement & Precision Teacher Lesson Guide Presentation 2 b. Exercise: Measuring Tools & Units Which measuring tool and units you will use to measure: 1. Classroom 2. Desk 3. Pencil 10

Middle School Measurement & Precision Teacher Lesson Guide Presentation 3. U Measure it See exercise: “U Measure it” provided in the handout . a) Use paper ruler (fig. 1) & Surgical blade (fig. 5) and provide the following dimensions: • Total and 1/2 of the surgical blade length • The widest part of the blade • The separation between teeth b) Use a normal ruler (or any other more precise measuring tool) and measure the same points described in (a). 11

Middle School Measurement & Precision Teacher Lesson Guide Presentation 3. U Measure it Cont. c) Compare results from (a: paper ruler) and (b: accurate ruler) in terms of accuracy and precision Table 2. Measurements of Surgical Blade Group Total Height ½ Height Widest part Separation between teeth (inches) No. (inches) Paper Normal ruler ruler 1 2 3 4 5 12

Middle School Measurement & Precision Teacher Lesson Guide Presentation U Measure it Cont. d) Report at least the one dimension of the surgical blade in exercise b) using 3 significant figures and the respective tolerance interval. Example: 2. 3 ± 0. 05 cm or from 2. 25 cm to 2. 35 cm. c) Explain the range of "tolerance” e) Explain why the selection of appropriate measurement tools is important in data calculation, design and manufacturing process. 13

Middle School Measurement & Precision Teacher Lesson Guide Presentation Exercise 4. Zero Waste - U Design it Use the surgical blade (fig. 5) and the provided sheet of paper (8 ½x 11”). a) What are the steps you would need to take if you were designing and manufacturing surgical blades as shown in the picture? b) How many surgical blades can you manufacture from a sheet of paper (8 ½x 11”). Consider minimum waste of material and maximum product. c) Draw the possible options for manufacturing the surgical blade and demonstrate the most efficient-zero waste distribution design. Figure 5 14

Middle School Measurement & Precision Teacher Lesson Guide Presentation Answers. Zero Waste - U Design it The most efficient-zero waste distribution design: Total 19 units 8 blades vertical blades 11 blades in horizontal position 15