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2013 Summer Camp for Teachers- Greentech

“Made in Florida”

Metrology: Accuracy, Precision & Tolerance Lesson Plan

Danielly Orozco - Curriculum coordinator

Florida Advanced Technological Education Center

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2013 Summer Camp for Teachers- Greentech

Presentation Outline

• MIF Lesson Plan overview (madeinflorida.org)

• Review Theory

• Hands on Exercise-Sample Lesson

• Discussion & Questions

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2013 Summer Camp for Teachers- Greentech

Metrology: Accuracy, Precision & Tolerance Lesson Plan

Nature of the Lesson

Participants are challenged to understand the importance of measurements, accuracy,

precision & tolerance.

Objectives

• To select and apply techniques and tools to accurately estimate measurements to

appropriate levels of precision and accuracy required in real world situations.

• To integrate and apply science, math, and technology.

• To understand the concept of unit systems and application in problem solving and

computation

Subject Areas

Science, Computer Technology, Math and Tech Education

.

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2013 Summer Camp for Teachers- Greentech

Review Theory. Cont.

Metrology

The science of measurement

Includes all theoretical and practical aspects of measurement

Greek μέτρον (metron), "measure" + "λόγος" (logos)

Measurements

Help us describe the world and everything in it.

ie. length, volume, weight, time, temperature, electricity, speed and

countless other properties.

Standardized Unit System

• International System of Units (SI) or Metric system &

• English system

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2013 Summer Camp for Teachers- Greentech

Review Theory, Cont.

Standardized Unit System

• International System of Units (SI)

From French: Le Système international d'unités, is the modern form of the

metric system.

Metric system: is a decimal system of measurement, (also called base ten

or occasionally denary) has ten as its base.

• English system

Used in a few nations, the only major industrial one being the United

States. It actually consists of two related systems—the U.S. Customary

System of units, used in the United States and dependencies, and the

British Imperial System.

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2013 Summer Camp for Teachers- Greentech

Review Theory, Cont.

Property International System of Units

(SI), 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)

Electricity Joules=newton meter

kg m2/s2

Foot pound-force

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2013 Summer Camp for Teachers- Greentech

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

xxx conditions show the same results

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2013 Summer Camp for Teachers- Greentech

Review Theory, Cont. Accuracy & Precision Examples

High Accuracy - Low Precision High Precision - Low Accuracy!!

True Value

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2013 Summer Camp for Teachers- Greentech

Tolerance Interval / Margin Error

Tolerance interval, Margin of Error, :

Is the amount by which the true value/measurement may vary above and

below the average value, or the ± Amount.

Tolerance intervals are related to engineering tolerances limits. Typically,

engineering tolerance limits define the maximum and minimum values for

a product to work correctly. Engineering tolerance limits may be specified

via geometric dimensioning and tolerancing

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2013 Summer Camp for Teachers- Greentech

1b. Exercise Tolerance Interval / Margin Error

Example:

Let’s measure widest part of Flater’s

Body (use FLATE’s ruler & Eng. ruler).

Provide tolerance interval

Tolerance interval:

2.25 ± 0.063 in

Ruler’s precision:

1/16 (0.063) in

Hi, My name is Flater!

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2013 Summer Camp for Teachers- Greentech

Review Theory, Cont.

• Significant Figures

The precision of any device is limited to the finest divisions on its scale.

Rules:

1. Leading zeros are not significant.

Ex: 0.000 52

has two significant digits

2. Trailing zeros in a number containing a decimal point are significant.

Ex: 12.2300 has six significant digits

3. 1300 scientific notation:

1.300 x 103 : four significant digits

1.3×103 : two significant digits

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2013 Summer Camp for Teachers- Greentech

Factors of Error

Parallax

This occurs when the measuring tool is read from inconsistent angles or

viewpoints

Meniscus errors

Occur at the surface of a liquid. This occurs when the reading is made from

either the top, the bottom, or the middle of the layer in a graduated cylinder.

Do you know which is the correct one?

Temperature

Has dramatic effects on mechanical devices, especially small metallic ones

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2013 Summer Camp for Teachers- Greentech

2. Exercise

Identifying Errors, Accuracy, and Precision

• Andre read the graduated cylinder from a standing position, while Lin read it

at water level.

• Our measure of the width of the microchip differed from the

manufacturer’s value by 1mm.

• Jackie’s group found the density of germanium exactly what the table said.

• The triple beam balance can detect masses as small as 0.01g.

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2013 Summer Camp for Teachers- Greentech

Measuring Tools & Their use

Figure 4. Long distance measuring tape

Figure 1. Ruler

Figure 2. Flexible measuring tape

Figure 3. Caliper

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2013 Summer Camp for Teachers- Greentech

Sample of Measuring Tools Cont.

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2013 Summer Camp for Teachers- Greentech

Measuring Tools

Calibration

Measuring devices should be calibrated against standards

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2013 Summer Camp for Teachers- Greentech

3. Exercise: Measuring Tools & Units

Which measuring tool and units you will use to measure:

• Distance from earth to the moon

• Football field

• Distance between electrons

Importance of calibration, precision & accuracy

Provide examples, ie: Medicine, Engineering

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2013 Summer Camp for Teachers- Greentech

4. Exercise: U Measure it

• Form Manufacturing Engineers Groups

• Provide design measurements for the five devices in each table, use

the most appropriate measurement tool.

• Write the results for each measurement in tables provided using

International System of Units (SI), Metric Units

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2013 Summer Camp for Teachers- Greentech

4. Exercise: U Measure it, Cont.

Provide the following information using

International System of Units (SI), Metric Units

• Hydrogen car: 50% Volume Capacity x Oxygen & Hydrogen

• Wind Energy: Length of blades

• Pressure sensor cell: L, W & thickness

• Solar bugs: area of solar panel

• Hydro - pneumatic connector: red & green color thickness

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2013 Summer Camp for Teachers- Greentech

Visit: made in florida.org Free lessons

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2013 Summer Camp for Teachers- Greentech

Additional Resources

These sites are useful and can be applied at any point(s) during this

lesson.

• Learning Challenges: http://flate.pbwiki.com

• Educational Pathways:

http://www.madeinflorida.org/Pathways.htm

• http://learners.gsfc.nasa.gov/challenge/discussiontopics1.html

• Measuring instruments visit:

http://www.gsource.us/catalog.php?type=47

THANK YOU