1. Review Theory Measurements Measurements help us describe the world and everything in it. Measurements can describe length, volume, weight, time, temperature,

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

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Measurement & PrecisionTeacher Lesson Guide Presentation

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http://www.globio.org/glossopedia/vocab.aspx?art_id=60&word_id=407&vocab=property&art_nm=measurements

http://www.fl-ate.org/

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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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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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

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Review Theory, Cont. Accuracy & Precision Examples

High Accuracy - Low Precision High Precision - Low Accuracy

True Value

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1a. ExerciseHow accurate & Precise are U?

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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

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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

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Measuring ToolsCalibration Measuring devices should be calibrated against standards

Example: A set of metric gauge blocks

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Exercise: Measuring Tools & Units Which measuring tool and units you will use to measure: 1. Classroom2. Desk3. Pencil

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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

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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).

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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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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


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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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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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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

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1. Review Theory Measurements Measurements help us describe the world and everything in it. Measurements can describe length, volume, weight, time, temperature,

Documents

ruler figure

normal ruler ruler

surgical blade figure

surgical blade length

accurate ruler

measurements results

surgical blade measure

ause paper ruler