Download Specific Heat!

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GOALS
Explain molecular
motion as it relates to
thermal energy
changes in terms of
conduction,
convection, and
radiation.
Intro Clip
Differentiate
between
conduction,
convection, and
radiation.
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Temperature and Heat
• Temperature is the
measurement of the avg.
KE of the molecules in a
material.
• Heat is the transfer of
KE from one material to
another.
Clip
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THERMAL ENERGY TRANSFER
CONDUCTION CONVECTION RADIATION
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Conduction
•The transfer of thermal
energy in solids.
•Materials must be in
direct contact with each
other!
• Ex: Heating of the
bottom of a pot on stove.
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Convection
•clip
• Transfer of thermal energy
in liquids and gases.
• The matter
actually
moves from
one place
to another.
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Radiation
•Transfer of
thermal
energy by
electromagnetic waves (we’ll
discuses these more later)
• Transferring energy through
space...NO MATTER IS
REQUIRED!
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Clip
How does heat effect
temperature?
• Adding Energy (heat) TO a
substance causes its
– Temperature to go UP!
• Taking energy (heat) AWAY from a
substance causes its
- Temperature to go DOWN!
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How does heat effect
temperature?
Box A : Has more energy (heat) – Has a higher temperature
Box B : Has less energy (heat) – Has a lower temperature
When they are combined
- Box A loses (releases) heat – temperature goes down (= to B)
- Box B gains (absorbs) heat – temperature goes up ( = to A)
Have you ever noticed that on
a hot summer day the ocean is
cooler than the hot sand?
Why? The sun has been beating down on both of them for the
same amount of time...........
Heat (radiation)
Heat (radiation)
Why aren't they the same temperature?
cool
hot
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It takes MORE thermal
energy to raise the
temperature of water than
the sand!
Water has a higher
SPECIFIC HEAT that sand!
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Specific Heat
• The amount of energy required
to raise the temperature of a
material (substance).
• It takes different amounts of
energy to make the same temp
change in different substances.
• We call the amount required:
Specific Heat!
Water needs a lot of
heat energy before its
temperature changes
Sand/ cement need a
little heat energy
before its temperature
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increases.
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Specific Heat Table
• The lower the specific heat
– the easier (faster) it is to
heat up and cool down.
• The higher the specific heat
– the harder (slower) it is to
heat up and cool down.
• Which substance would
lose its heat fastest?
• Which substance would
take longer to heat up?
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Calculating Specific Heat
The Greek letter Δ means “change in”
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Calorimeter
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Conduction can BEST be described as the transfer of
energy
A
B
C
D
by
by
by
by
traveling through space as waves
the movement of fluids
the expansion of gases
contact between particles
A copper ornament
has a mass of
0.0693 kg and
changes from a
temperature of
20.0°C to 27.4ºC.
How much heat
energy did it gain?
A 200 J
C 540 J
B 460 J
D 740 J
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