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

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.

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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

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, 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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2a. 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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2b. Exercise: Measuring Tools & Units Which measuring tool and units you will use to measure: 1. Classroom2. Desk3. Pencil

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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).

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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 No.

Total Height (inches)

½ Height (inches)

Widest part (inches)

Separation between teeth (inches)

Paper ruler

Normal ruler

Paper ruler

Normal ruler

Paper ruler

Normal ruler

1

2

3

4

5

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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.

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Exercise 4. Zero Waste - U Design it

Figure 5

Use the surgical blade (fig. 5) and the provided sheet of paper (8 ½x11”).

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.

c) 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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Documents

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