Transcript III. Unit Conversions - John Marshall High School

Journal 9/24
SWBAT:
Use dimensional analysis to convert between units.
1. What Metric unit would be appropriate to measure
the distance to Green Bay, WI?
2. Calculate with correct sig figs:
a)5.28 m+ 3.1 m
b) 150 m3  4 m
c) (1250 – (234.207/ 52.69))
3.
Find the error:
680,500,000 = 68.05 x 108
Hour 1 & 4
1.
2.
3.
4.
Discuss Lab- Post lab due Monday
DA notes
DA practice Sheet
Assign Lake Erie lab write-up – due Mon
Hour 3
1.
2.
3.
4.
Lab
Discuss Lab – Post lab due Monday
DA practice Sheet
Assign Lake Erie lab write-up – due Mon
Hour 5 & 7
1.
2.
3.
4.
5.
Prep lab
Lab
Discuss Lab – Post lab due Monday
DA practice Sheet
Assign Lake Erie lab write-up – due Mon
MEASUREMENT
Unit Conversions
Dimensional analysis
SI Prefix Conversions
1. Find the difference between the
exponents of the two prefixes.
2. Move the decimal that many places.
To the left
or right?
SI Prefix Conversions
532 m
0.532 km
= _______
NUMBER =
UNIT
NUMBER
UNIT
SI Prefix Conversions
move right
move left
Prefix
mega-
Symbol
M
Factor
106
kilo-
k
103
BASE UNIT
---
100
deci-
d
10-1
centi-
c
10-2
milli-
m
10-3
micro-

10-6
nano-
n
10-9
pico-
p
10-12
SI Prefix Conversions
1) 20 cm =
0.2
______________
m
2) 0.032 L =
32
______________
mL
Dimensional Analysis
 The

“Factor-Label” Method
Units, or “labels” are canceled, or “factored”
out
g
cm 

g
3
cm
3
Dimensional Analysis
 Steps:
1. Write your given (include number and label)
2. Line up conversion factors so units cancel.
3. Multiply all top numbers & divide by each
bottom number.
4. Check units & answer.
Dimensional Analysis
Unit equality – relationship that is equal to one
Example:
1 in = 2.54 cm
OR
2.54 cm = 1 in
Conversion Factor- fraction that uses unit equality,
ratio is equal to one.
1 in
=
=
2.54 cm
2.54 cm
1 in
1
Dimensional Analysis
 Your
European hairdresser wants to
cut your hair 8.0 cm shorter. How
many inches will he be cutting off?
cm
in
8.0 cm
1 in
2.54 cm
= 3.1 in
Dimensional Analysis
 How
many milliliters are in 1.00 quart of
milk? (1 L = 1.057 qt)
qt
mL
1.00 qt

1L
1000 mL
1.057 qt
1L
= 946 mL
Dimensional Analysis
 You
have 1.5 pounds of gold. Find its
volume in cm3 if the density of gold is
19.3 g/cm3.
cm3
lb
1.5 lb 1 kg
2.2 lb
1000 g
1 cm3
1 kg
19.3 g
= 35 cm3
Dimensional Analysis
 How
many liters of water would fill a
container that measures 75.0 in3?
in3
L
75.0 in3 (2.54 cm)3
(1 in)3
1L
1000 cm3
= 1.23 L
Dimensional Analysis
 The
Rockets need 550 cm for a 1st
down. How many yards is this?
cm
550 cm
yd
1 in
1 ft 1 yd
2.54 cm 12 in 3 ft
= 6.0 yd
Dimensional Analysis
A
piece of wire is 1.3 m long. How
many 1.5-cm pieces can be cut from
this wire?
cm
1.3 m
pieces
100 cm
1 piece
1m
1.5 cm
= 86 pieces
REVISED Weekly Schedule
Monday
Urine Article
Tuesday
Dimensional analysis
Pre-lab lake Erie
Density & Temperature
Wednesday
Thursday
Friday
Lake Erie lab; How toxic? WS
DA Quiz all DA HW due!
Prep Urine Lab