MEASUREMENT

 

Learning to measure properly is key to any tech program. The tools of the trade include the tape measure, the ruler and the micrometer.


Lesson Outline: This lesson will introduce you to the metric and imperial systems of measurement and the routine conversions you will need to make throughout the engines unit.

Objectives: By the end of the lesson, students will be able to:

  • Convert metric dimensions to imperial
  • Describe the use of a micrometer
  • Measure fasteners accurately
  • Measure diameter, circumference and length

Key terms: - Micrometer, verner calliper, metric, imperial

Content:

The metric system is the official system of measurement in Canada.

The basic unit of measure is the meter (m).
1m=100 cm
1m=1000 mm etc.
Every unit is easily divisible by 10, making conversions easy.
   

In tech studies, it is also important to know the Imperial System because that is what they use in the United States. Given that the US is our greates trading partner, we are often obliged to manufacture and buy products measured in imperial.

The Imperial system is more complex because we end up working with FRACTIONS!
The basic unit of measure for distance is the foot (ft).
1 foot=12 inches

Try to figure our why there are 12 inches in a foot instead of 10 and be prepared to share your answer with the class. http://en.wikipedia.org/wiki/Imperial_unit#Measures_of_length

Working with fractions is difficult for a lot of people, but practice is the best way to get better at anything.

In this photo, you can see that the inches have been divided in half.
(½ inch)

When writing measurements on paper, we use a single apostrophe to represent feet, and a double apostrophe to represent inches.

5 foot 2 inches would be written 5’ 2”.

Here the inches of the ruler have been divided into quarters. (1/4 inch or 1/4”)

Obviously we can get more and more complex, to the point where it would be difficult to measure by eye.

 

Take a look at the ruler to the left and see if you can figure out the smallest fractions of an inch represented.


Practice:

Go to the Funbrain Website now and do the activities for the metric and imperial rulers. http://www.funbrain.com/measure/index.html

Ruler exercise 1
Read the Ruler Game http://rickyspears.com/rulergame/ Alright, now you’ve mastered the ruler, you can try the ultimate challenge. Read the rules then click on the button that says START NEW GAME in the yellow box.


To take measurements and plan projects, you’ll have to be able to add and subtract fractions.

Remember that the key to these operations is finding the common denominator.

Add ½” and 1/8” for example. What is the common denominator?

Convert both fractions so they have a CD.
Then add them. 4/8” + 1/8” = 5/8”


Tools of the trade:

  


You’ve probably already had a chance to use a ruler and a tape measure in shop class.

One important measuring tool for the mechanic is the vernier caliper. The one pictured here is adequate for our purposes and is available at most hardware stores.
   

Calipers can be used to measure lengths and diameters.

Review the following site for an overview of how to read a micrometer.
http://www.phy.uct.ac.za/courses/c1lab/vernier1.html

   
Click the photo to the left to enlarge it, and give the reading of the calliper in Imperial Measurement.
   
Try this one in metric.

Quiz:

Now that you've read the lesson, you can take the quiz.

References:

http://www.funbrain.com/measure/index.html
http://rickyspears.com/rulergame/
http://www.phy.uct.ac.za/courses/c1lab/vernier1.html