Lesson 1.3 Measurement

Preface

The need for very accurate measurements during the design process goes back at least to the time of the great pyramids. Clearly, the ancient Egyptians used the basics of surveying to build the pyramids. The concepts of measuring angles and lengths must have been well developed at that time.

In order to measure something, an essential feature is the use of a common measurement system. In the U.S., both the Metric (SI) system and the Standard (Customary) system are used. The rest of the world, including England, uses the metric system. During this course, students will experience opportunities to use measurement when making a sketch or drawing or a prototype and when using computer modeling systems. Students will also learn that to switch between the two measurement systems.

Concepts

1. In the United States, we use both Standard and Metric systems of measurement.

2. Being able to measure accurately is important at school and at home, at work and when pursuing hobbies.

3. Precision measuring tools are needed for accuracy, but tools must be used correctly to ensure accurate measurements are taken.

4. Quality workmanship and accurate measurements with precise instruments are necessary to successfully solve problems.

Performance Objectives

It is expected that students will:

· Demonstrate the ability to measure accurately with different devices and scales.

· Explain how to measure in different contexts.

· Measure using both the Standard and Metric systems.

Essential Questions

1. Do you think the U.S. should convert to all metric measuring, or should the U.S. stay with using both the Standard and Metric systems? Why?

2. Why don’t we use such measurement forms as the hand span, cubit, and pace very often today?

3. Give two reasons why precision measuring tools are not always accurate.

(See Key Terms Next Page)

Key Terms

Accuracy / The condition or quality of being true, correct, or exact; precision; exactness. The degree of correctness of a quantity or expression.
Customary System / Also referred to as the English system of measuring. The measuring system based on the foot, second, and pound as units of length, time, weight, or mass.
Denominator / Divisor; the number below the line in a fraction.
Caliper / A measuring tool with two usually adjustable jaws used especially to measure thickness or diameter.
Diameter / A straight line passing from side to side through the center of a circle or sphere.
Measurement / Collecting data in a quantifiable manner.
Metric System / The decimal measuring system based on the meter, liter, and gram as units of length, capacity, and weight or mass.
Micrometer / A gauge which measures small distances or thicknesses.
Numerator / The number above the line in a fraction showing how many of the parts indicated by the denominator is taken.
Precision / The degree to which several measurements or calculations show the same or similar results.
Unit / A standard quantity in terms of which other quantities may be expressed.