# ME301: Measurement & Experimentation Laboratory

Unit 5: Measurements of Linear Dimension   The measurement of length is as fundamental to mechanical engineering as it is to everyday life (consider the variety of length scales we use on a day-to-day basis: the hand, finger, foot, rod, nose, and hair!)  Coupled with other information, length measurements can yield complex geometric information.  In this unit, you will learn about a few tools that enable us to precisely measure lengths and related quantities over vastly different length scales.  Many more tools are available than can be described here.

This unit should take you 10 hours to complete.

☐    Subunit 5.1: 2 hours

☐    Subunit 5.2: 1 hour

☐    Subunit 5.3: 1 hour

☐    Subunit 5.4: 1 hours

☐    Assignment: 4 hours

☐    End of Unit Self-Assessment: 1 hour

Unit5 Learning Outcomes
Upon successful completion of this unit, the student will be able to:

• Understand, use, and convert various common units for length measurement.
• Research and understand modern instrumentation for length measurements.
• Communicate technical information to others.
• Use simulated instrumentation.

5.1 Units and Standards   - Reading: Simon-Fraser University: Stephen Lower’s Chem1 General Chemistry Virtual Textbook: “Understanding the Units of Scientific Measurement” Link: Simon-Fraser University: Stephen Lower’s Chem1 General Chemistry Virtual Textbook: “Understanding the Units of Scientific Measurement” (PDF)

Instructions: Review this chapter, focusing on the short section on length.  Note that there may be an error in the figure on length scales regarding the size of a hydrogen atom.  Look up the size elsewhere and compare.  To view in a PDF file, scroll to the bottom and click on the “download” link.

5.2 Calipers   Note: Calipers are claw-like devices used for measuring linear dimension.  They are particularly useful for measuring the outer diameters of cylindrical or round objects or the internal diameters of pipes and the like.  They are one of the few instruments that still makes use of Vernier scales.

Instructions: Read this discussion of the Vernier scale and test your knowledge with the Java applet.  If you have access to a set of calipers, you may wish to practice with measuring the thickness of a series of nominally identical coins.

5.3 The Sine Bar   - Web Media: Wisc-ONLINE: Barbara Anderegg’s “SINE BAR” Link: Wisc-ONLINE: Barbara Anderegg’s “SINE BAR” (Adobe Flash)

Instructions: View this slide show, which demonstrates the use of a sine bar for measuring angles.  The sine bar is often used in conjunction with gauge blocks in machine shops for precise manufacturing of equipment.  You may wish to review the trigonometry involved in the use of sine bars.

5.4 Instrumentation   - Activity: The Saylor Foundation’s Instrumentation Activity Instructions: Modern instrumentation is capable of precise and accurate measurements of lengths over many length scales.  The most current information about commercially available instrumentation is readily accessible via informational advertisements on YouTube.  For each of the following items (5.4.1-5.4.5 listed below), review at least one such advertisement and answer the following questions:

1.      What are the technical capabilities of the instrument?
2.      What is the cost of the instrument?
3.      What is the level of training required to operate and obtain meaningful data from the instrument?
4.      What types of systems are amenable to study by the instrument?

In your search, you may find many other types of instrumentation for similar purposes with slightly different names.  The list bellow will help you get you started.

Example: Type “profilometer” into the YouTube search window and peruse the resulting product videos.

5.4.1 Profilometers/Optical Comparators   5.4.2 Coordinate Measuring Machines   5.4.3 Sonar/Depth Measurements   5.4.4 Optical/Laser Distance Measurements   5.4.5 Global Positioning System Measurements   Unit 5 Assessment   - Assessment: The Saylor Foundation's "ME301: Unit 5 Quiz" Link: The Saylor Foundation's "ME301: Unit 5 Quiz"

`````` Instructions: Please complete the linked assessment.

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