Using Numbers in Science
AND
Metric System
1
Parts of a Measurement
1. The value (numerical portion)
2. The unit (describes what units)
3. The name of substance being measured
EX:
1 teaspoon salt
2 liters of pop
2
The Metric System &
• Scientific Measurements made in metric units
• Referred to as the International System or SI
units
• Based on the decimal system
• Related by powers of 10
• Each type has a base unit
• Use prefixes to refer to a unit larger or smaller
than the base by some power of 10
3
SI (International System) units
Length
meter
m
Mass
kilogram
kg
Temperature
Kelvin
K
Time
second
S
Volume
Liter
L
Centigrade or Celsius = ⁰C
This is the unit we will use in lab for temperatures!
4
Prefixes for Metric Units <1
deci (d) = 1/10 = 0.1
centi (c) = 1/100 = 0.01
milli (m) = 1/1000 = 0.001
decimilli (dm) 10-4
centimilli (cm) 10-5
micro (µ)10-6 = 1/100000 = 0.000001
5
Prefixes for Metric Units >1
kilo (k) = 1000
hecto (h) = 100
deka (da) = 10
6
Metric Unit Conversions
kilo
hecto
deca
Base
Unit
deci
centi
milli
micro
k
h
da
gram (g)
d
c
mm
μ
1000
100
10
liter (L)
0.1
0.01
0.001
0.000001
103
102
101
meter (m)
10-1
10-2
10-3
10-4
10-5
10-6
7
Millimeter
Could be the
diameter of a
straight pin
Centimeter
Which is about the
length of a sugar cube
1 inch = 2.54 centimeters
A paperclip could be about
2.54cm long
9
Meter
10
Kilometer
Mass
12
Mass
13
Volume
14
Volume
15
Class Activity 1 – Understanding Metric Units
Part A - Matching
A. Length
B. Mass
C. Temperature
D.Time
E. Volume (liquids)
Part B – select the best prefix
Class Activity – Part C
What are the correct abbreviations?
____ milligram
____ milliliter
____ liter
_____centimeter
____ kilogram
____ millimeter
____ kilometer
____ gram
____ meter
____ millisecond
____ microgram
_____ hectometer
____ micrometer
____ microliter
17
Part D
18
19
20
Review Questions
1. What does the prefix
"milli" mean?
2. A liter is a little more
than a _______
A. millionth
B. thousandth
C. hundredth
A. pound
B. gallon
C. quart
21
3. What is a good height
for a basketball player?
A. 6 meters
B. 2 meters
C. 6 millimeters
4. Which is the longer
distance to run ?
A.
B.
C.
50 meters
50 kilometers
50 miles
22
5. Which value would
be right for the mass
of a
A. 17 mg
B. 17 g
C. 17 kg
6. Which value would
be right for the
mass of a
A. 460 mg
B. 460 g
C. 460 kg
What units would best be used to
record the length, volume or mass
of these objects?