Transcript Introduction to English and Metric Measurement

Introduction to Measurement
Developing Standard and Metric Measuring Skills
Design and Modeling
© 2011 Project Lead The Way, Inc.
Measurement Systems
Two types of measurement systems exist.
– Standard (Customary)
- Metric (SI or International System)
Where are these used?
• Standard measurement is used in Liberia,
Myanmar, and the United States of
America.
• Metric measurement is used in every other
country in the world.
Standard (Customary) System
Inches
Fractions
The Whole Inch
First Half
Second Half
¼
¾
1/
3/
5/
7/
8
8
8
8
2
4
8
1/
16
3/
16
5/
16
7/
16
9/
16
11/
16
13/
16
15/
16
16
Steps in Using the
Standard (Customary) System
1. Find out how many parts the inches are divided into.
Count the spaces in 1 inch.
This number will be the denominator.
2. Count the number of whole inches.
Write down the number.
3. Count the number of spaces after the last whole inch.
This number will be the numerator.
4. Reduce fraction, if necessary.
Let’s Review
1
Count Step
Whole
2 Inches
Find Step
Numerator
7 3
Find Step
Denominator
16 1
Reduce Fraction,
Step 4 If Necessary
Let’s Practice
What is the distance from the end of the ruler to A? 𝟏 𝟒 in.
What is the distance from the end of the ruler to B? 𝟏𝟓 𝟏𝟔 in.
What is the distance from the end of the ruler to C? 1 𝟑 𝟒 in.
What is the distance from the end of the ruler to D? 2 𝟑 𝟖 in.
What is the distance from the end of the ruler to E? 3 𝟏 𝟏𝟔 in.
Metric System
International System of Units (SI)
Millimeters and
Centimeters
Decimals
1 mm = 0.1 cm
5 mm = 0.5 cm
10 mm = 1 cm
Steps in Using the
Metric (SI) System
1. Count the number of whole centimeters
(cm).
These are the larger lines with numbers
2. Count the number of lines after the whole
number.
The smaller lines are millimeters (mm).
3. Put in correct terms.
Since mm are 1/10th of a cm, if you
measure 7 marks after 1 cm, the measure
is 1.7 cm or 17 mm long.
Let’s Practice
What is the distance from the end of the ruler to A?
What is the distance from the end of the ruler to B?
What is the distance from the end of the ruler to C?
What is the distance from the end of the ruler to D?
What is the distance from the end of the ruler to E?
4 mm = 0.4 cm
19 mm = 1.9 cm
37 mm = 3.7 cm
63 mm = 6.3 cm
73 mm = 7.3 cm
Unit Conversion
• Sometimes we need to know a measurement in
a unit different than the unit presented
• Conversion factor
o A ratio (fraction) that relates a measurement
in one unit to the same measurement in
another unit
o
Example: To convert meters to centimeters
o Start with the equivalency 100 cm = 1 m
• The ratio of centimeters to meters is 100:1
100 cm
•
is the conversion factor
1m
Unit Conversion
Desired Unit
12 in.
• feet to inches: 1 ft = 12 in. or
1 ft
Given Unit
◦ The ratio of inches to feet is 12:1
• miles to feet: 1 mi = 5280 ft or
5280 ft
1 mi
∘ The ratio of feet to miles is 5280:1
Unit Conversion
• Conversion factor
– Using a conversion factor to cancel unwanted units is
similar to canceling common factors when multiplying
fractions
5
7
·
=
7
3
5
3
Unit Conversion
Example: Convert 17 yards to feet
Unit Conversion
Your Turn: Convert 4 feet to inches
More Unit Conversions
Your Turn
4 blocks = 1 inch in length
What is the conversion factor to convert inches to blocks?
4 blocks
1 in.
• 6 in. = __________________blocks
• 2 ½ in. = __________________blocks
• 4 ¾ in. = __________________blocks
Common Conversions
The Gateway Formula Sheet provides many different
length equivalencies.
We can use these to
create conversion
factors.
Common Conversions
What conversion factor would you use to convert
7 feet to a measurement in meters?
1m
3.28 ft
Desired Unit
Given Unit
Convert 7 feet to meters
1m
7 ft ×
= 2.13 m
3.28 ft
Common Conversions
What conversion factor would you use to convert
19 inches to a measurement in centimeters?
2.54 cm
1 in.
Desired Unit
Given Unit
Convert 19 in. to cm
2.54 cm
19 in. ×
= 48.26 cm
1 in.
Common Conversions
What conversion factor would you use to convert
4 yards to a measurement in meters?
First, convert yards to feet
3 ft
4 yd ×
= 12 ft
1 yd
Next, convert feet to meters
1m
12 ft ×
= 3.66 m
3.28 ft
4 yd = 3.66 m
Let’s Practice
You used a meter stick to measure
your window for new shades.
However, the shade packages list the
measurements in English units.
Luckily your cell phone has a
calculator so that you can quickly
convert your 81.3 cm by 91.4 cm
window opening to English units.
What size is your window using
English units? Round to the nearest
inch.
Let’s Practice
Convert 81.3 cm x 91.4 cm to English
units. Round to the nearest inch.
Therefore, the window opening is 32 in. x 36 in.
Image Resources
Microsoft, Inc. (2008). Clip Art. Retrieved October 7, 2008, from
http://office.microsoft.com/en-us/clipart/default.aspx