1. Review Theory Measurements Measurements help us describe the world and everything in it....
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Transcript of 1. Review Theory Measurements Measurements help us describe the world and everything in it....
1. Review Theory Measurements Measurements help us describe the world and everything in it. Measurements can describe length, volume, weight, time, temperature, and countless other properties.
Standardized Unit SystemMetric system and the English system
This work is funded under grant DUE# 0802436 from the National Science Foundation Advanced Technological Education (ATE) program. Opinions and findings expressed herein are those of the authors and do not necessarily reflect the views of the National Science Foundation. © Copyright 2012 FLATE
High School
Measurement & PrecisionTeacher Lesson Guide Presentation
1
Review Theory, Cont. Property Metric Units English Units
Length Meters, kilometers Inch, foot, mile
Volume cubic centimeters cubic inches
Fluid Volume Milliliter, liter
Quart, gallon
Mass Milligram, gram, kilogram
Ounce, pound, ton
Temperature degree Celsius (˚C)
degree Fahrenheit (˚F)
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High School
Measurement & PrecisionTeacher Lesson Guide Presentation
Review Theory • 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 xxx conditions show the same results
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High School
Measurement & PrecisionTeacher Lesson Guide Presentation
Review Theory, Cont.
• Accuracy Degree of closeness of measurements results to the true value
• Precision, reproducibility or repeatabilityThe degree to which repeated measurements of a quantity under unchanged
conditions show the same results
High School
Measurement & PrecisionTeacher Lesson Guide Presentation
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Review Theory, Cont. Accuracy & Precision Examples
High Accuracy - Low Precision High Precision - Low Accuracy
True Value
High School
Measurement & PrecisionTeacher Lesson Guide Presentation
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1a. ExerciseHow accurate & Precise are U?
High School
Measurement & PrecisionTeacher Lesson Guide Presentation
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High School
Measurement & PrecisionTeacher Lesson Guide Presentation
1b. 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!
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Measuring Tools & Their use
Figure 4. Long distance measuring tape
High School
Measurement & PrecisionTeacher Lesson Guide Presentation
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Figure 1. Ruler
Figure 2. Flexible measuring tape
Figure 3. Caliper
Sample of Measuring Tools Cont.
Graduated cylinder, measuring cup, water velocity-meter, thermometer, analytical balance
High School
Measurement & PrecisionTeacher Lesson Guide Presentation
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Measuring ToolsCalibration Measuring devices should be calibrated against standards
Example: A set of metric gauge blocks
High School
Measurement & PrecisionTeacher Lesson Guide Presentation
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Exercise: Measuring Tools & Units Which measuring tool and units you will use to measure: 1. Classroom2. Desk3. Pencil
High School
Measurement & PrecisionTeacher Lesson Guide Presentation
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2. Part A - U Measure ita) Use paper ruler (fig.1), Surgical blade (fig. 10) and Reciprocating Action Blade (fig.
11) and provide the following dimensions:
Surgical Blade – figure 10: total and 1/2 of the surgical blade length, the widest part of the blade, and separation between teeth.
Reciprocating Action Blade – Figure 11: total length L, outside diameters D1, D2, and D3, as indicated in figure 11.
Write the results for each measurement in tables 1 and 3 respectively
High School
Measurement & PrecisionTeacher Lesson Guide Presentation
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2. Part A - U Measure it. Cont.
b) Use a normal ruler or any other more precise measuring tool, (optional). Measure the same points described in (a).
In addition, for the surgical blade measure angles between the teeth, angles 1, 2, and 3. See figure 10 for details.
Write the results in table 1, 2, and 3 accordingly.
Prepare a graphical chart to represent “accuracy” and “precision” of the data, (see figures 8 – High accuracy Low precision and figure 9 – High Precision Low Accuracy). Compare results from exercise (a) and (b).
High School
Measurement & PrecisionTeacher Lesson Guide Presentation
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2. Part A - U Measure it. Cont.c) Compare results from (a: paper ruler) and (b: accurate ruler) in terms of accuracy and precision
Table 1. Measurements of Surgical Blade
Group No.
Total Height (cms)
½ Height (cms)
Widest part (cms)
Separation between teeth (mm)
Paper ruler
Normal ruler
Paper ruler
Normal ruler
Paper ruler
Normal ruler
1
2
3
4
5
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High School
Measurement & PrecisionTeacher Lesson Guide Presentation
2. Part A - U Measure it. Cont.
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High School
Measurement & PrecisionTeacher Lesson Guide Presentation
Group No
Table 2 - Exercise 2b and 2cSurgical Blade – Angle Measurements in degrees (o)
Angle between teeth
Angle 1 Angle 2 Angle3
1
2
3
4
5
2. Part A - U Measure it. Cont.
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High School
Measurement & PrecisionTeacher Lesson Guide Presentation
Table 3 - Reciprocating Action Blade Measurements for exercises 3(a), 3(b), and 3(c)Reciprocating Action Blade Measurements
Group No.
Total length - L
(centimeters)
Diameter D1
(centimeters)
Diameter D2
(centimeters)
Diameter D3
(millimeters)ruler 1
figure 1ruler 2
normal ruler
ruler 1 ruler 2 ruler 1 ruler 2 ruler 1 ruler 2
12345
U Measure it Cont.
d) Accuracy and precision: of students should mark a dot representing the total length obtained in the exercises 2a and 2b. Accuracy: how close the individual measurements of the total length of the surgical blade agree with the correct value.
Precision: check for reproducibility of measurements between groups.
e) 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.
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High School
Measurement & PrecisionTeacher Lesson Guide Presentation
Exercise 3. Part B-Zero Waste Surgical Blade- U Design it
Figure 10
Use the surgical blade and reciprocating action blade from example 3 (figure 10 and 11) and a clean sheet of paper (11x8 ½”).
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 ½x11”). Consider minimum waste of material and maximum product.
Draw the possible options for manufacturing the surgical blade and demonstrate the most efficient-zero waste distribution design.
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High School
Measurement & PrecisionTeacher Lesson Guide Presentation
Answers. Zero Waste - U Design it
The most efficient-zero waste distribution design:Total19 units
8 bl
ades
ver
tical
bla
des
11 blades in horizontal position
19
High School
Measurement & PrecisionTeacher Lesson Guide Presentation