Measurements

1
Measurements

• An Introduction to All Things Quantitative

2
Objectives

• After this presentation, you should be able to
• Describe the need for measuring things.
• Define quantitative in your own words.
• Name and describe five properties that can be
  measured.
• Name the two systems of measurement in use and
  how they differ.

3
Why Measure?

• Measurements are among the earliest tools created
  by human beings.
• They were created to accomplish many tasks
  including
• The construction of dwellings and monuments
• The fashioning of clothing
• The bartering of food or raw materials

4
What Can be Measured?

• There are many physical properties that can be
  measured in the world around us.
• Any property that can be measured and assigned a
  numerical value is said to be a quantitative
  (think quantity) property.
• Examples of quantitative properties include
  length, weight, brightness, heat, loudness,
  volume, as well as many more.

5
More Qualitative Properties

• Time
• Mass
• Amount
• Electrical current
• Area
• Speed
• Velocity
• Density

6
Systems of Measurement

• In use today, there are two major systems of
  measurement, the Imperial units (upon which our
  system of measurements are largely based) and the
  metric system.
• We, in the United States are probably most
  familiar with the Imperial system, however in the
  majority of the rest of the world, the metric
  system is the dominant system of measurements.

7
History of Measurement

• Length
• A cubit is the length of the forearm from the tip
  of the elbow to the tip of the middle finger.
• The cubit was dived into two spans (the distance
  between the tip of the thumb to the tip of the
  pinky in an outstretched hand).
• It was also divided into six hands (the width of
  the hand)
• It was also dived into 24 digits (the width of
  the middle finger)

8
History of Measurement

• The inch, foot, and yard were derived from these
  units.
• The roman foot was divided into 12 unciae and 16
  digits.
• The roman mile consisted of 5000 feet, or 1000
  paces.
• Queen Elizabeth I changed the mile to what we
  know it as today, 5280ft.

9
(No Transcript)
10
The Need for Standardization

• During the development of measurements, the same
  unit came to measure slightly different amounts
  depending upon where in the world it was used, by
  whom it was being used, or who was the ruler of
  the country/empire at the time.
• This discontinuity lead to trade disputes and
  made life difficult for merchantsa change was
  needed.

11
The Metric System (SI)

• The metric system (often abbreviated as the SI
  system due to its French roots) is the
  measurement system preferred by scientists around
  the world.
• It was created by the French and is used by all
  but three nations (Burma, Liberia, and The United
  States) as their official system of measurement.

12
The Metric System

• Perhaps the most significant advantage to the
  metric system is the fact that it address the
  seemingly arbitrary relationship between
  different units for measuring the same property
  within the imperial system.
• Examples Why are there 12 inches in a foot, but
  three feet in a yard? Why are their 2 pints in a
  quart, but 4 quarts in a gallon?

13
The Metric System

• Because it is based on powers of 10, the metric
  system makes it easy to go from small units to
  large units within the base (length, mass,
  volumeetc).
• For example, there are 10 millimeter in 1
  centimeter, there are 1000 meters in 1 kilometer,
  there are 10 grams in one decagram.

14
The Metric System

• Another important characteristic of the metric
  system is the interconnectedness of the base
  units of mass, length, and volume and time.
• If we construct a box whose sides are all 1cm x
  1cm, it would fit exactly 1 milliliter of water
  whose mass would be exactly 1 gram.
• If we construct a pendulum whose length is 1
  meter, its period (the time it takes to complete
  a swing) is 1 second.

15
Wrap up

• Why measure?
• What is a quantitative property?
• What are five properties that can be measured?
• What are the two dominant systems of measurement
  in use today and how do they differ?
• Body Measurement lab