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TRANSCRIPT
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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