Introduction to Measurement Developing Standard and Metric Measuring Skills Design and Modeling 2011 Project Lead The Way, Inc.
Why Learn to Measure? Valuable skill for a job Valuable skill for hobbies Valuable skill for every day life
Measurement Systems Two types of measurement systems exist. Standard (Customary) - Metric (SI or International System)
Standard (Customary) System Inches Fractions The Whole Inch First Half Second Half ¼ ¾ 1 / 8 3 / 8 5 / 8 7 / 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 3 7 16 Find Denominator Step 1 Reduce Fraction, Step 4 If Necessary
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? 1 4 in. 15 16 in. 1 3 4 in. 2 3 8 in. 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 1 m
Unit Conversion Desired Unit feet to inches: 1 ft = 12 in. or 12 in. 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 17.2 yards to feet 17.2 yd 1 X 3 ft 1 yd = 51.6 ft 1 = 51.6 ft 3 ft = 1 yd
Unit Conversion Example: Convert 17.2 yards to feet 17.2 yd 1 X 3 ft 1 yd = 51.6 ft 1 = 51.6 ft 3 ft = 1 yd
Unit Conversion Your Turn: Convert 4 feet to inches 4 ft 1 X 12 in. 1 ft = 48 in. 1 = 48 in. 12 in. = 1 ft
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. 4 blocks = 24 6 in. = blocks 1 in. 2.5 in. 4 blocks = 10 2 ½ in. = blocks 1 in. 4.75 in. 4 blocks = 19 4 ¾ in. = blocks 1 in.
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? 1 m 3.28 ft Desired Unit Given Unit Convert 7 feet to meters 7 ft 1 m 3.28 ft = 2.13 m
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 19 in. 2.54 cm 1 in. = 48.26 cm
Common Conversions What conversion factor would you use to convert 4 yards to a measurement in meters? First, convert yards to feet 4 yd 3 ft 1 yd = 12 ft Next, convert feet to meters 12 ft 1m 3.28 ft = 3.66 m 4 yd = 3.66 m
Unit Conversion Example: Convert 3-5 to inches 3 ft + 5 in. = 3 ft 1 = 36 in. 1 = 41 in. 12 in. 1 ft + 5 in. 12 in. = 1 ft + 5 in.
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. 81.3 cm 1 in. 2.54 cm = 32 in. 91.4 cm 1 in. 2.54 cm = 36 in. 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