Internal%20energy:%20total%20amount%20of%20the%20energy%20of%20the%20particles%20that%20compose%20matter

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• Internal energy total amount of the energy of
  the particles that compose matter

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What is the difference between heat, temperature
and thermal energy?

• Temperature the measure of the average kinetic
  energy of the vibrating particles that compose an
  object
• Heat the quantity of thermal energy transferred
  from a hotter to a colder object
• Internal Energy the total amount of internal
  energy possessed by the particles that compose
  matter

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• When matter gets warmer, the atoms or molecules
  in the matter move faster.

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• All mattersolid, liquid, and gasis composed of
  continually jiggling atoms or molecules, which
  have KE.

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21.1 Temperature

• The higher the temperature of a substance, the
  faster the motion of its molecules.
• This is also referred to as the Kinetic Theory
• all matter is made of atoms and molecules that
  are moving.
• The higher the temperature, the faster the
  particles move.
• Given the same temperature, heavier particles
  move slower than lighter particles.

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21.1 Temperature

• Measure temperature by showing expansion and
  contraction of a liquid in a glass tube.
• Three Scales (, Fahrenheit, Celsius and Kelvin)
• Fahrenheit (32-212 F)
• Celsius (0-100 C)
• Kelvin is a universal scale with no upper limit.
  (0 K or absolute zero to )

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21.1 Temperature
This thermometer measures temperature on both
Fahrenheit and Celsius scales.
Puzzler K C 273 Which is hotter, 500 K or
500 C? 500 C, because 500 C is 773 K
273 K
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21.1 Temperature

• Which has more thermal energy, a cup of boiling
  water or Lake Michigan in winter?

Lake Michigan! The water molecules are moving
faster in the boiling cup of water, but there are
vastly more water molecules in Lake Michigan.
Are the water molecules in an ice cube moving?
Yes. Motion of molecules stops at absolute zero.
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21.1 Temperature
What is the relationship between the temperature
of a substance and the speed of its molecules?
The higher the temperature of a substance, the
faster is the motion of its molecules and the
greater their average KE.
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Physics and Particles

• Particle is a general term used to describe
  molecules, atoms and sub-atomic particles

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Starter Questions

• 1. How does a thermometer work

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Matter is changing state
solid
Increasing Avg. KE Increasing Temp.
Particle speed is increasing
melting
freezing
liquid
evaporation
condensation
gas
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21.1 Temperature

• Temperature and Kinetic Energy

Temperature is related to the average kinetic
energy of the atoms and molecules in a
substance. The faster the molecules move, the
______________ the temperature and the
_____________ the average kinetic energy and the
__________ the particle speed.
greater
greater
greater
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21.2 Heat

• Heat is the quantity of thermal energy
  transferred from a hotter to a colder substance.
• Heat always flows from a substance with a higher
  temperature to a substance with a lower
  temperature.
• Heat flows only when there is a difference in
  temperature.
• Heat units are calories or joules.

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hotter
21.2 Heat
Entropy! Flow from higher to lower energy state.
Just as water will not flow uphill by itself,
regardless of the relative amounts of water in
the reservoirs, heat will not flow from a cooler
substance into a hotter substance by itself.
colder
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21.2 Heat
What causes heat to flow?
A difference in temperature between objects in
thermal contact.
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21.4 Internal Energy

• When a substance takes in or gives off heat, its
  internal energy changes.

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21.3 Thermal Equilibrium
What happens when a warmer substance comes in
contact with a cooler substance?

• Heat flows between two objects of different
  temperature until they have the same temperature.
  (2nd law of thermodyamics)
• The loss of thermal energy from the warmer object
  equals the gain of thermal energy for the cooler
  object

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21.8 Thermal Expansion

• Most forms of mattersolids, liquids, and
  gasesexpand when they are heated and contract
  when they are cooled.

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21.8 Thermal Expansion

• When the temperature of a substance is increased,
  its molecules jiggle faster and normally tend to
  move farther apart.
• This results in an expansion of the substance.
• Gases generally expand or contract much more than
  liquids.
• Liquids generally expand or contract more than
  solids.

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Starter Question 2How does a thermometer work?

• The kinetic theory be used to explain expansion
  and contraction of materials when the temperature
  of the material changes.
• As the temperature rises, heat is transferred
  from the surroundings to the liquid inside the
  thermometer and the molecules that compose the
  liquid vibrate faster. This causes the liquid to
  expand and rise.
• As the temperature falls, heat is transferred
  away from the liquid inside to the surroundings
  and the molecules that compose this liquid slow
  down. This causes the liquid to contract.

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• The liquid in the thermometer stops rising or
  falling when thermal equilibrium is reached (no
  more heat flow!)

Air temperature Liquid temperature
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21.6 Specific Heat Capacity

• Do copper, clay and water have the same chemical
  composition?
• No. Copper is composed of Cu atoms and water is
  composed of H2O molecules. Clay is a complex
  silicate.
• The difference in chemical composition influences
  how copper, clay and water respond when heat is
  transferred.

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21.6 Specific Heat Capacity
The specific heat capacity of a substance is the
quantity of heat required to raise 1 g of a
substance by 1 degree Celsius.
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21.6 Specific Heat Capacity
A substance with a high specific heat capacity
can absorb a large quantity of heat before it
will raise in temperature (water has a high
specific heat). A substance with a low specific
heat requires relatively little heat to raise its
temperature (copper has a low specific heat).
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21.6 Specific Heat Capacity
highest
lowest
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21.6 Specific Heat Capacity

• think!
• Which has a higher specific heat capacitywater
  or sand? Explain.

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21.6 Specific Heat Capacity

• think!
• Which has a higher specific heat capacitywater
  or sand? Explain.
• Answer
• Water has a greater heat capacity than sand.
  Water is much slower to warm in the hot sun and
  slower to cool at night. Sands low heat
  capacity, shown by how quickly it warms in the
  morning and how quickly it cools at night,
  affects local climates.

Good conductors have a low specific heat capacity!
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21.6 Specific Heat Capacity
A gram of water requires 1 calorie of energy to
raise the temperature 1C. It takes only about
one eighth as much energy to raise the
temperature of a gram of iron by the same amount.
The capacity of a substance to store heat depends
on its chemical composition.
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21.6 Specific Heat Capacity
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• 6. What is the difference between a substance
  with a high specific heat and a low specific heat
  capacity?

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• Substances with a low specific heat (e.g.,
  metals) need very little heat to raise
  temperature
• Good conductors, not good absorbers, do not hold
  onto heat well
• Substances with a high specific heat need a large
  quantity of heat to raise temperature.
• Poor conductors, good absorbers, store and hold
  onto heat well

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• 7. How does the specific heat of water help to
  moderate climate?

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Friday

• Heat Flow ExamplesHome Heating and Cooling
• a) Summer time flow
• b) Winter time flow
• Water and Specific Heat
• a) Sea Breezes
• b) Moderating effect of water (Edmonton vs. Cork)
• Reason for the seasons
• Tilt of Earths Rotational Axis (23.5o)
• Insolation Angle (same radiation, different area)
• c) Absorption vs. Reflection

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Winter Vs. Summer Heat Flow

• In winter
• -Heat loss from inside (warmer) to outside
  (colder)
• -Heating system must operate to transfer thermal
  energy from fuel to fluid to room to keep house
  warm

• In summer
• -Heat gain from outside (warmer) to inside
  (cooler)
• - Cooling system must operate to transfer
  incoming heat entering the house back to the
  outside

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Why do we need heating systems?

• What do the green arrows represent?
• How does this heat flow affect the temperature of
  the air inside the home?
• Where does the energy come from that increases
  the temperature of the air inside the home?

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Explain why the heat flow for a home is different
in the winter vs. the summer.
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22.2 Convection

• Convection currents are produced by uneven
  heating.
• During the day, the land is warmer than the air,
  and a sea breeze results.

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22.2 Convection

• Convection currents are produced by uneven
  heating.
• During the day, the land is warmer than the air,
  and a sea breeze results.
• At night, the land is cooler than the water, so
  the air flows in the other direction.

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Generation of Sea Breezes
Day
Convection
Air above the sea remains cooler and moves on
land to replace the land air that rose
Air above the land heats more rapidly and rises
Sea breeze

• Land
• low specific heat
• heat and cools rapidly
• less resistant to temperature change

• Sea
• high specific heat
• heats and cools slowly
• more resistant to temperature change

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Generation of Sea Breezes
Night
Air above the ground is cooler than the air
above the water and moves over the sea to replace
the sea air that rose
Air above the water is warmer than the air above
the land and rises
Land Breeze

• Land
• low specific heat
• heat and cools rapidly
• less resistant to temperature change

• Sea
• high specific heat
• heats and cools slowly
• more resistant to temperature change

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Generation of Sea Breezes
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21.7 The High Specific Heat Capacity of Water

• The property of water to resist changes in
  temperature improves the climate in many places.

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21.7 The High Specific Heat Capacity of Water
Water has a high specific heat and is
transparent, so it takes more energy to heat up
than land does.
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Moderating Effect of Water

• During the summer, surrounding air is cooled by
  the water and keeps the coast cooler than the
  intercontinental locations.
• During the winter, the surrounding air is warmed
  by the water and keeps the coast warmer than the
  intercontinental locations.

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21.7 The High Specific Heat Capacity of Water
Waters capacity to store heat affects the global
climate. Water stores and hold heat well because
of its high specific heat.
Gulf Stream brings warm water northeast from the
Caribbean.
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Thermal Front

• The Gulf Stream (warm water from equator)
• meets
• The Labrador Current (cold water from polar
  region)

Labrador Current
Gulf Stream
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21.7 The High Specific Heat Capacity of Water

• Climate of Europe

Look at a world globe and notice the high
latitude of Europe. Both Europe and Canada get
about the same amount of the suns energy per
square kilometer.
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Marine Climate
Continental Climate
Cork
Edmonton
Same insolation angle, different climate due to
proximity to water and the warming effect from
the Gulf Stream
http//www.sampleireland.com/weather-in-ireland-ye
ar-round.html
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The Gulf Stream brings warm winters to Ireland
and the prevailing winds off the Atlantic carry
with them rain. It means grass can grow almost
all year round creating the lush sweeping
pastures of the Emerald Isle. Today they make up
93 percent of all farmland. No other country in
Europe has quite as much grass as Ireland.
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21.7 The High Specific Heat Capacity of Water

• Climate of America

• On the west coast, air moves from the Pacific
  Ocean to the land.
• In winter, the water warms the air that moves
  over it and warms the western coastal regions of
  North America.
• In summer, the water cools the air and the
  western coastal regions are cooled.

The central interior of a large continent usually
experiences extremes of temperature. Land, with
a lower specific heat capacity, gets hot in
summer but cools rapidly in winter.
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Reason for the Seasons
2
Changing Angle of Sunlight

• The hemisphere tilted toward the Sun receives
  sunlight at higher angles than the hemisphere
  tilted away from the Sun.
• Higher insolation angle means greater intensity
  of radiant energy (the sun shines more directly
  on a smaller area).

Summer in Northern Hemisphere
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Identify the Seasons and the Equinox or Solstice,
and comment about the number of daylight vs.
night hours
Season _________ Equinox or Solstice
_________
Season _________ Equinox or Solstice
Season _________ Equinox or Solstice
Season ________ Equinox or Solstice
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Identify the Seasons and the Equinox or Solstice
Equal day and night12hr and 12 hr
Season _________ Equinox or Solstice
spring
Less daylight hours, more night hours
Less night hours, more daylight hours
winter
Season _________ Equinox or Solstice
summer
Season _________ Equinox or Solstice
fall
Season _________ Equinox or Solstice
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• Heat can be transferred by conduction, by
  convection, and by radiation.

http//www.nd.edu/ysun/Yang/PhysicsAnimation/coll
ection/transportP.swf
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22.1 Conduction

• In conduction, collisions between particles
  transfer thermal energy, without any overall
  transfer of matter.

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22.1 Conduction
Heat from the flame causes atoms and free
electrons in the end of the metal to move faster
and jostle against others. The energy of
vibrating atoms increases along the length of the
rod.
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22.2 Convection

• In convection, heat is transferred by movement of
  the hotter substance from one place to another.

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22.2 Convection

• Convection occurs in all fluids.
• Convection currents transfer heat in air.

Hot, less dense fluid rises in the presence of
cooler, more dense fluid.
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22.2 Convection

• Convection occurs in all fluids.
• Convection currents transfer heat in air.
• Convection currents transfer heat in liquid.

When fluid particles at the bottom of the pan
begin to vibrate faster, they expand and decrease
in density, making the hotter fluid more buoyant.
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22.3 Radiation

• In radiation, heat is transmitted in the form of
  radiant energy, or electromagnetic waves.

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22.3 Radiation
Most of the heat from a fireplace goes up the
chimney by convection. The heat that warms us
comes to us by radiation.
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Heat Transfer 1

• Which heat transfer occurs from particle to
  particle during direct contact of substances?

• a) Conduction
• b) Convection
• c) Radiation
• Conduction and Convection
• Conduction, convection and radiation

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Heat Transfer 1

• Which heat transfer occurs from particle to
  particle during direct contact of substances?

• a) Conduction
• b) Convection
• c) Radiation
• Conduction and Convection
• Conduction, convection and radiation

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Heat Transfer 2

• Which heat transfer can occur through a vacuum or
  through matter?

• a) Conduction
• b) Convection
• c) Radiation
• Conduction and Convection
• Conduction, convection and radiation

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Heat Transfer 2

• Which heat transfer can occur through a vacuum or
  through matter?

• a) Conduction
• b) Convection
• c) Radiation
• Conduction and Convection
• Conduction, convection and radiation

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Heat Transfer 3

• Which heat transfer is based on density
  differences in a substance and gravity?

• a) Conduction
• b) Convection
• c) Radiation
• Conduction and Convection
• Conduction, convection and radiation

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Heat Transfer 3

• Which heat transfer is based on density
  differences in a substance and gravity?

• a) Conduction
• b) Convection
• c) Radiation
• Conduction and Convection
• Conduction, convection and radiation

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Heat Transfer 4

• Which heat transfer occurs through the movement
  of the heated substance?

• a) Conduction
• b) Convection
• c) Radiation
• Conduction and Convection
• Conduction, convection and radiation

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Heat Transfer 4

• Which heat transfer occurs through the movement
  of the heated substance?

• a) Conduction
• b) Convection
• c) Radiation
• Conduction and Convection
• Conduction, convection and radiation

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Heat Transfer 5

• Which heat transfer is characterized by
  transmission by electromagnetic waves?

• a) Conduction
• b) Convection
• c) Radiation
• Conduction and Convection
• Conduction, convection and radiation

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Heat Transfer 5

• Which heat transfer is characterized by
  transmission by electromagnetic waves?

• a) Conduction
• b) Convection
• c) Radiation
• Conduction and Convection
• Conduction, convection and radiation

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Heat Transfer 6

• Which heat transfer processes can only occur
  through matter?

• a) Conduction
• b) Convection
• c) Radiation
• Conduction and Convection
• Conduction, convection and radiation

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Heat Transfer 6

• Which heat transfer processes can only occur
  through matter?

• a) Conduction
• b) Convection
• c) Radiation
• Conduction and Convection
• Conduction, convection and radiation

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• Radiation is caused by moving electrons or
  charged particles in matter. The faster the
  particles move, the higher the frequency of the
  electromagnetic radiation.

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22.3 Radiation

1. Radio waves send signals through the air.

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22.3 Radiation

1. Radio waves send signals through the air.
2. You feel infrared waves as heat.

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22.3 Radiation

1. Radio waves send signals through the air.
2. You feel infrared waves as heat.
3. A visible form of radiant energy is light waves.

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• 11. What happens to the frequency of radiant
  energy as the temperature of the substance
  increases or decreases?

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• The frequency of radiant energy increases as the
  temperature of the substance increases.

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http//mail.jsd.k12.ca.us/bf/bflibrary/images/elec
tromagnetic-spectrum.jpg