Temperature Scales &
Temperature Conversions
There are 3 ways to measure temperature:
 Fahrenheit
 Centigrade (or Celsius)
 Kelvin
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What temperatures we measure
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Measuring
temperature comes up
all the time.
Is my child sick?
Should I wear a coat?
Are we going
swimming after lunch?
We use 3 basic scales to
measure the temperature.
Fahrenheit is the most common, the weather reporter
gives us air temperature in Fahrenheit degrees, although
they hardly ever mention the UNITS.
Centigrade or Celsius is more common in science and in
Europe, but most bank clocks that give a temperature
reading do so in both F and C degrees.
Kelvin is not used much outside of science, and is
named after LORD KELVIN who sounds like he might have been in
STAR WARS but was in fact not in any movies that I am aware of. (Use the
FORCE Luke!)
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Compare and Contrast the scales
what numbers can we put into the boxes?
SCALE
Water
Boils
F°
212 °
C°
K
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Water Freezes
Room
Temperature
72 °
Absolute
Zero
Compare and Contrast the scales
keep thinking
SCALE
Water Boils
Water
Freezes
Room Temp.
F°
212 °
32 °
72 °
C°
K
5
Absolute
Zero
0°
0
Compare and Contrast the scales
almost done…
SCALE
Water Boils
Water
Freezes
Room Temp.
F°
212 °
32 °
72 °
C°
100 °
0°
22 °
K
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273
Absolute
Zero
- 273 °
0
Compare and Contrast the scales
look at all the boxes once more please
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SCALE
Water Boils
Water
Freezes
Room Temp.
Absolute
Zero
F°
212 °
32 °
72 °
- 460 °
C°
100 °
0°
22 °
- 273 °
K
373
273
295
0
Compare and Contrast the scales
make a mental note of the rules below…
Temp.
Scale
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Water
Boils
Water
Freezes
Room
Temp.
Absolute
Zero
F°
Fahrenheit is always expressed in
degrees, with the symbol °
C°
Centigrade is always expressed in
degrees, with the symbol °
K
Kelvin is always expressed in KELVINS
and we do not use the symbol °
Converting F ° to C °
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It’s time to think. Let’s
convert the temperature
of 212 ° F to C °.
Using the chart you can
see that the answer is
100 ° C.
How can we figure that
out?
Converting 212 °F into C °
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IN REGENTS CHEM YOU DO
NOT HAVE TO BE ABLE TO GO
FROM CENTIGRADE TO
FAHRENHEIT TEMPERATURES.
THIS SLIDE HAS BEEN
CHANGED FROM THE PAST TO
THIS WORK FREE DIAGRAM
SLIDE.
ENJOY THIS LITTLE BREAK
FROM THOUGHT.
Converting F ° to C ° more practice
REST
NOW.
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The KELVIN SCALE
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This time the chart at
right has the Kelvin
Scale as well
Kelvin is used mostly
in science and not in
“regular life”
Kelvin conversions are
easy to make from
Centigrade
Converting to Kelvin from °C
Convert 100° C to Kelvin
The chart shows us
that the correct answer
is 373 K.
NOTE: We do not use
the ° symbol with Kelvin
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Converting to Kelvin from °C
The Rule to Remember
is this:
K = C + 273
so…
Water freezes at 0°C,
which equates to how
many Kelvin?
K = 0 + 273
14K = 273
Converting to Kelvin from °C
The Rule to Remember
is this:
K = C + 273
More Practice
Convert 72°C to Kelvin
K = 72 + 273
K = 345
(Kelvin is easy)
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Temperature Scales
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Three Temperature scales in science:
Fahrenheit, centigrade, and Kelvin
We can convert from one to another if we
use the right formulas
Kelvin does not use the ° symbol
Chemistry is very cool and we are getting
smarter every day