1. SI Measurement System Presentation Name Course Name
Unit # – Lesson #.# – Lesson Name
SI Measurement System
Introduction to Engineering Design
© 2012 Project Lead The Way, Inc.

2. The International System of Units (SI)
Presentation Name
Course Name
Unit # – Lesson #.# – Lesson Name
The International System of Units (SI)
The International System of Units (SI) is a system of units of measurement consisting of seven base units
The abbreviation SI is from the French “Systeme Internationale d’unites”
SI is the most widely used system of measurement in the world
The United States is the only industrialized nation that has not adopted the SI system

3. The International System of Units (SI)
Presentation Name
Course Name
Unit # – Lesson #.# – Lesson Name
The International System of Units (SI)
The modern SI system evolved from the older metric system.
Metric system only had three base units centimeters, grams, and seconds. While the SI system has evolved to seven base units listed below
The base unit is the fundamental unit (basic unit, essential unit) in a system of measurement
*The kilogram not gram is the base unit
Base Unit Name
Symbol
Measurement
meter m
length
kilogram* kg
mass
second s
time
ampere A
electric current
kelvin K
Temperature
candela cd
luminous intensity (brightness)
mole
mol
quantity, the amount of something (usually the amount of a substance) 6.02x1023 of something

4. The International System of Units
Presentation Name
Course Name
Unit # – Lesson #.# – Lesson Name
The International System of Units
Often referred to as the metric scale (cause SI came from metric)
Prefixes indicate an integer power of 10
Power of 10
Prefix
Abbreviation
101
deca- da
102
hecto- h
103
kilo- k
106
Mega- M
109
Giga- G
1012
Tera- T
Power of 10
Prefix
Abbreviation
10-1
deci- d
10-2
centi- c
10-3
milli- m
10-6
micro-
10-9
nano- n
10-12
pico- p

5. Presentation Name
Course Name
Unit # – Lesson #.# – Lesson Name

6. Recording Measurements
Presentation Name
Course Name
Unit # – Lesson #.# – Lesson Name
Recording Measurements
A measurement always includes a value
A measurement always includes unit of measurement
A measurement always involves uncertainty
A measurement is the best estimate of a quantity
Bob weighs 142 lbs. That is no exact. No one can weigh exactly 142 lbs.
Value
Unit

7. Presentation Name
Course Name
Unit # – Lesson #.# – Lesson Name
Metric Scale
A typical metric scale ruler often includes a 30+ centimeter scale
Each centimeter is divided into 10 millimeters

8. The Millimeter
The millimeter is the smallest increment found on a typical metric scale
1 mm which is 0.1 cm

9. The Millimeter
The next larger marking on a metric scale shows 5 millimeters
5 mm which is 0.5 cm

10. The Millimeter
Largest markings on a metric scale represent centimeters (cm)
These are the only marks that are actually numbered
1 cm = 10 mm

11. Measurement: Using a Decimal Scale
Presentation Name
Course Name
Unit # – Lesson #.# – Lesson Name
Measurement: Using a Decimal Scale
How long is the rectangle?
Let’s look a little closer

12. Measurement: Using a Decimal Scale
Presentation Name
Course Name
Unit # – Lesson #.# – Lesson Name
Measurement: Using a Decimal Scale
How long is the rectangle?

13. Recording a Measurement
Presentation Name
Course Name
Unit # – Lesson #.# – Lesson Name
Recording a Measurement
How long is the rectangle?
Remember the general rule
Decimal Scaled Instruments – Record all digits that you can certainly determine from the scale markings and estimate one more digit
Best Estimate = 3.84 cm or 38.4 mm

14. Presentation Name
Course Name
Unit # – Lesson #.# – Lesson Name
Your Turn
How would you record the length of this rectangle?
6.32 cm or 63.2 mm

15. Find the width of the blue and red rectangle
Presentation Name
Course Name
Unit # – Lesson #.# – Lesson Name
Find the width of the blue and red rectangle
BLUE
RED

16. Start Activity