How Scientists
Measure
Unit 1.1 – Chapter 1 Section 2
International System of Units
(SI System)
• The modern form of the metric system used by
science
• Uses a base unit for each type (quantity) of
measurement
Quantity
SI Base Unit
Symbol
Length
m
Volume
L
Mass
g
Density
g/mL
Temperature
K
SI System Prefixes
• Many of the units can scale by factors of 10 to
change the measurement larger or smaller
• Prefixes are added to the base unit name to show
scale
K
H
D
Base
D
C
M
Kilo
Hecta
Deca
(g, m,
L)
Deci
Centi
Milli
King
Henry
Died
By
Drinking
Chocolate
Milk
Identify each measurement
• 173 m _________
62.0 km _________
• 28.4 L _________
5.17 mL _________
Converting in the SI System
Conversions
• 1 Kilo = 1000 Base Units
• 1 km =
meters
• 1 Hecta = 100 Base Units
• 1 hL =
Liters
• 1 Deca = 10 Base Units
• 1 Dg =
grams
More Conversions
• 10 deci = 1 Base Units
• 1 decigram =
grams
• 100 centi = 1 Base Units
• 1 centimeter =
meters
• 1000 milli = 1 Base Units
• 1 milliliter =
Liters
How To Do Conversions?
• If I have 63 mg of sugar, how many grams do I have?
• 63 mg = _________ grams
How To Do Conversions?
• If I ran 5 kilometers, how many meters did I run?
• 5 km = _________ meters
Other Units
• Temperature: measure of
an objects kinetic energy
• Celsius Scale (º C) based on water
• Kelvin Scale ( K ) –
based on motion
• 0 K = absolute zero, all
motion stops
Converting ºC to K
• ˚ C + 273 = Kelvin
• Practice
• 0 ˚C =
K
• 100 ˚C =
K
• -10 ˚ C =
K
Converting K to ˚C
• Remember ˚C + 273 = Kelvin
• How many ˚C is 300 K?
Weight vs. Mass
• Mass = how much matter an object has
• Weight = measures the pull of gravity on mass
• * Think of space: objects can become weightless,
not massless
• The worlds
tallest building,
The Burj Khalifa,
is 828 ______
high
• This is a 2 ______
bottle of soda
• Human body
temperature is
98.6˚Farenheit or
37˚ _______