1. Metric System Basics

2. Metric System Importance of standard units of measure
U.S. is the only major industrialized country in the world not using the metric system
What can be measured?
Length: distance between two points
Temperature: the amount of heat gained or released by an object
Mass: the amount of space an object takes up
Time: how long it takes an event (i.e. reaction) to happen

3. Review of Measurements
Units
Symbols
Equipment
Length
meters m
ruler
Mass
grams g
balance/scale
Volume
Liters L
graduated cylinder
Temperature
degrees Celsius °C
thermometer
Time
seconds s
stop watch

4. Base Units and Metric Measurements
The metric system is based on a base unit that corresponds to a certain kind of measurement
Length = meter
Volume = liter
Mass = gram
The metric system is based on powers of ten:
10 mg = 1 cg
10 cg = 1 dg
10 dg = 1 g
1L = 1dm3 = 1kg kg = 1L = 2.2lbs = 1dm3
1cc = 1mL = 4°C H2O
(temperature at which water is most dense)

5. Metric System The three prefixes that we will use the most are: kilo
centi
milli
kilo
hecto
deca
Base Units
meter
gram
liter
deci
centi
milli

6. Metric System So to measure length, a meter is the base unit
Length of a tree branch
1.5 meters
Length of a room
5 meters
Length of a ball of twine stretched out
25 meters

7. Metric System Prefixes plus base units make up the metric system
Example:
Centi + meter = Centimeter
Kilo + liter = Kiloliter
What if you need to measure a longer distance? For example, what is the distance from your house to school?
Let’s say you live approximately 10 miles from school
10 miles = meters
16093 is a big number, but what if you could add a prefix onto the base unit to make it easier to manage:
16093 meters = kilometers

8. Metric System
The prefixes are based on powers of ten. What does this mean?
From each prefix every “step” is either:
10 times larger or
10 times smaller
For example
Centimeters are 10 times larger than millimeters
1 centimeter = 10 millimeters
kilo
hecto
deca
Base Units
meter
gram
liter
deci
centi
milli

9. Metric System
Centimeters are 10 times larger than millimeters so it takes more millimeters for the same length
1 centimeter = 10 millimeters
Example not to scale 40 41
1 mm 40 41
1 cm

10. Base Units and Derived Units
Base Units – a unit in a system of measurement that is based on the object or event in the physical world mass (kg) length (m) time (s) temperature (°C)
Derived Units – combinations of base units; examples: volume - cm3, dm3 speed - m/s, mi/hr density - g/mL, g/cm3
Standard Units: Mass – kg Volume – L Length – m Time s

11. Metric System Kilo 1000 (thousand) Hecta 100 (hundred) Deca 10 (ten)
Base (one)
Deci 1/10 (.10) (tenth)
Centi 1/100 (.01) (hundredth)
Milli 1/1000 (.001) (thousandth)
**The following are base units: Mass – g Volume – L Length – m Time s

12. PLEASE COMMIT THE FOLLOWING CONVERSION FACTORS TO MEMORY!!
Metric System Factors
The metric system is based off factors of ten:
10 mm = 1 cm 10 cm = 1 dm 10 dm = 1 m 10 m = 1 dkm 10 dkm = 1 hm 10 hm = 1 km
PLEASE COMMIT THE FOLLOWING CONVERSION FACTORS TO MEMORY!!
1g = 1 mL = 1 cm “milli’s” in 1 “centi”
1000 g = 1 kg mg in 1 g
100 cg = 1 g

13. Dimensional Analysis
A problem solving technique that uses conversion factors that equal one
Conversion factors are ratios of equivalent values used to express the same quantity in different units
When you convert from a large unit to a small unit, the number of units must increase. A meter is a much smaller unit than a kilometer, one one-thousandth smaller. So, there are 48,000 meters in 48 kilometers

14. How to Solve Dimensional Analysis Problems:
Example Problem: How many centigrams in 5 grams? 1. Write what you know grams
2. Set up a conversion factor grams X ________
a. Write what unit you want to get rid of on the bottom of the proportion.
5 grams x ________ grams

15. How to Solve Dimensional Analysis Problems:
b. Write what unit you want to get to on the top of the proportion.
5 grams x centigrams grams
3. Compare the two units in the proportion. A “1” is written next to the bigger unit. Then ask yourself, how many of the smaller units are in the bigger unit? Write that number on the other side of the proportion.
5 grams x 100 centigrams gram
4. Solve.
(5 x 100) = 500 centigrams