N. Sassaman – SAMS
2012-2013
Temperature,
Thermal Energy and Heat

Temperature is a measure of the average
kinetic energy of the individual particles in
matter.
Temperature,
Thermal Energy and Heat

Temperature changes cause the level of the
liquid inside a thermometer to rise and fall.
Temperature,
Thermal Energy and Heat

The three
common scales
for measuring
temperature are
the Fahrenheit,
Celsius, and
Kelvin scales.

The total energy of all the particles of a
substance.

Depends on:
◦ Temperature
◦ Number of particles (amount of substance)
◦ Substance itself

For example:
◦ A large pot of boiling water has more thermal
energy than a small cup of boiling water.
Kinetic energy
(motion)
Temperature
(average)
Thermal energy
(total)







To convert a Fahrenheit temperature to a Celsius
temperature, use the following formula:
ºC = 5/9 (ºF – 32)
For example, if the temperature in your classroom is
68ºF, what is the temperature in degrees Celsius?
ºC = 5/9 (68 – 32)
ºC = 5/9 X 36
ºC = 20
The temperature of your classroom is 20ºC.
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
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Practice Problem
While at the beach, you measure the ocean
temperature as 77ºF. What is the temperature of the
ocean in degrees Celsius?
25ºC
1.
2.
3.
4.
5.
6.
7.
8.
9.
No – thermal energy depends not only on
temperature, but also the amount and type
of material.
A) Celsius B) 0 C) 0° D) 212°
B
E
A
F
D
C
G
- The Transfer of Heat

If two objects have different temperatures,
heat will flow from the warmer object to the
colder one.
Temperature,
Thermal Energy and Heat


http://www.neok12.com/php/watch.php?v=zX615658021a7c56507d7977&t=HeatTemperature
http://www.neok12.com/php/watch.php?v=zX61086240457a69466a7677&t=HeatTemperature
Energy
Measured
Temperature
Thermal Energy
Heat
Average kinetic
energy of particles
Total energy of all
particles in an
object
Usually used when
discussing transfer
Units
Fahrenheit or Celsius
degrees, Kelvins
Joules
Joules
Temperature,
Thermal Energy and Heat
HIGH specific heat = heats up slowly
LOW specific heat = heats up quickly



The amount of energy required to
raise the temperature of 1 kg of a
substance by 1 Kelvin.
A material with a high
specific heat can absorb a
great deal of thermal
energy without a great
change in temperature.
Example: sand gets hotter faster than water
(sand has lower specific heat than water)
http://oceanservice.noaa.gov/education/pd/oceans_weather_climate/me
dia/specific_heat.swf


Specific heat of a substance =
Change in Energy (heat/energy needed in J)
Mass (kg) x Change in temp. (K)
Change in energy (heat/energy needed) =
Mass x Specific heat x Change in temp.
(kg)
J = Joules
(J/(kg·K))
kg = kilograms
(K)
K = Kelvin
- The Transfer of Heat


http://www.teachersdomain.org/asset/lsps07_int_heattra
nsfer/
http://www.nd.edu/~ysun/Yang/PhysicsAnimation/collect
ion/transportP.swf
Main Idea
Heat can be transferred in three ways.
Detail
Detail
Conduction–
transfer of heat
between particles
without the
movement of
matter.
Convection–
transfer of heat
by the movement
of currents in a
fluid.
*direct contact of
materials*
*hot rises, cool
sinks*
Detail
Radiation–
transfer of
energy by
electromagnetic
waves.
*through ‘empty’
space*
1.
2.
3.
4.
5.
6.
Conduction
Radiation
Conduction
Conduction
Convection
Radiation
7.
8.
9.
10.
11.
12.
Conduction
Conductor
Convection current
Insulator
Radiation
Convection
Conductor examples:
Metals (silver, stainless
steel); tile floor.
Insulator examples:
Wood, wool, straw, paper,
cork, gases, rug, clothes,
blankets, feathers, blubber,
fiberglass.
**low specific heat value**
** high specific heat value**
Thermal Energy
and States of Matter

Most matter on Earth can exist in three
states–solid, liquid, and gas.
- The Properties of Water


Ice is solid water, the familiar form of water is a
liquid, and the water vapor in the air is a gas.
http://www.media.pearson.com.au/schools/cw/au_sch_whalley_sf1_1/int/matter.html
- States of Matter

A fixed, closely packed arrangement of
particles causes a solid to have a definite
shape and volume.
- States of Matter

Because its particles are free to move, a liquid
has no definite shape. However, it does have
a definite volume.
- States of Matter

As they move, gas particles spread apart,
filling all the space available. Thus, a gas has
neither definite shape nor definite volume.
- Changes of State

The change in state from a solid to a liquid is
called melting.
- Changes of State

The change of state from liquid to solid is
called freezing.
- The Properties of Water



Water moves between the liquid and gaseous states
by evaporation and condensation. Water moves
between the liquid and solid states by freezing and
melting.
http://www.media.pearson.com.au/schools/cw/au_sch_whalley_sf1_1/int/2_slg.html
http://www.footprints-science.co.uk/flash/states.swf
Thermal Energy
and States of Matter


Matter can change from one state to another when
thermal energy is absorbed or released.
http://www.brainpop.com/science/matterandchemistry/matterchangingstates/
- Changes of State
A beaker of ice at
–10ºC was slowly
heated to 110ºC. The
changes in the
temperature of the
water over time were
recorded. The data
were plotted on the
graph shown here.

Reading Graphs:
◦ What two variables are
plotted on the graph?
◦ Temperature (ºC) on the
y-axis, time (minutes) on
the x-axis

Reading Graphs:
◦ What is happening to the
temperature of the water
during segment C of the
graph?
◦ The temperature is rising
from 0ºC to 100ºC.

Interpreting Data:
◦ What does the
temperature value for
segment B represent? For
segment D?
◦ Segment B: melting point
of ice; segment D:
boiling point of water

Drawing Conclusions:
◦ What change of state is
occurring during
segment B of the graph?
For segment D?
◦ Change from solid to
liquid; change from
liquid to gas

Inferring:
◦ In which segment, A or E,
do the water molecules
have more thermal
energy? Explain your
reasoning.
◦ Water molecules in
segment E have more
thermal energy because
they are at a higher
temperature.
Thermal Energy
and States of Matter

As the thermal energy of matter increases, its
particles spread out and the substance expands. A
bimetallic strip in a thermostat contracts or
expands depending on whether it is cooled or
warmed.
Thermal Energy
and States of Matter

Using a word in a sentence helps you think about how best to
explain the word. After you read the section, reread the
paragraphs that contain definitions of Key Terms. Use the
information you have learned to write a meaningful sentence for
each Key Term.
Key Terms:
state
evaporation
change of state
boiling
melting
condensation
freezing
thermal expansion
Examples:
If vaporization
Water
can existtakes
in three
place
different
at the surface
states, or
of a
forms. it is called evaporation.
liquid,
The physical change from one state of matter to
At
higheristemperatures,
vaporization
another
called a change
of state. can occur
below the surface of a liquid as well. This process
The
change
of state from a solid to a liquid is
is
called
boiling.
called
melting.
A change
from the gas state to the liquid state is
called
condensation.
The change
of state from a liquid to a solid is
The
expanding
called
freezing. of matter when it is heated is
known as thermal expansion.
1.
2.
3.
4.
An increase in
thermal energy
(increases movement
of particles).
All extra energy goes
into breaking solid
bonds instead of
raising temperature.
Thermal expansion!
Ties would
buckle/break in
summer.
Solid, liquid, gas
5.
6.
7.
8.
9.
10.
11.
12.
Melting
States
Condensation
Evaporation
Boiling
Freezing
Thermal expansion
Change of state