16
At
16. 2 ppt
Heat in the
Atmosphere
CH 15 Prentice Hall
p.509-514
Egg Demonstration
• Problem:
– What will happen when the egg
is placed on the bottle once the
paper is lit?
• Hypothesis:
• Observations:
Egg Demonstration
• Observations:
• Identify:
– Where the pressure was low
and high.
– What was the wall?
Soda Can
• Problem:
– What will happen to the
heated can when the opening
is sealed with water.
• Hypothesis:
– The can will….
• Observations:
1,2,3 Candle
• Problem: How will placing a drinking glass
over lit candles sitting in a pie pan filled with
water affect the water in the pan?
• Hypothesis (one for each picture)
1,2,3 Candle Diagram
1,2,3 Candle Diagram
• Explain what
happened?
– Where was the
pressure high and
low?
– What was the
wall in this
situation?
– Why was the
pressure low?
Heat Transfer
Chapter 16 Section 2
Pages 532-535
Thermal Energy
•
Is the total energy of motion in the
molecules of a substance.
•
Gases are made of molecules that are
constantly moving. The faster they are moving
the more energy they have.
Fast
More
Energy
Slow
Less
Energy
Temperature
•
•
The average amount of energy of motion in
the molecules of a substance.
It is a measure of how hot or cold
something is.
More
Energy
Warmer
Less
Energy
Cooler
Measuring Temperature
•
Thermometer- An instrument used to
measure the temperature, consisting
of a thin, glass tube with a bulb on
one end that contains a liquid, usually
mercury or alcohol.
– Liquids expand when heated or contract
when cooled.
– It is measured in degrees Celsius or
Fahrenheit.
•
•
Freezing 0°C = 32°F
Boiling 100°C = 212°F
Speed of Molecules & Temp
•
What happens
to the speed of
the molecules
when
temperature is
increased?
•
What happens
to the amount
of times the
walls are hit?
Temperature and Volume
•
What happens to
the volume of a
gas when it is
heated?
Air Molecule Model Situation 3
Faster
Molecules
Slower
Molecules
• Heating air molecules increases their energy
making them move faster.
• As a result, they will hit the wall more often,
moving the wall to the right.
– Lowers the pressure on the warmer side
– Increases pressure on the cooler side.
Air Molecule Model Situation 4
Slower
Molecules
Faster
Molecules
• Cooling air molecules decreases their energy
making them move slower.
• As a result, they will hit the wall less often,
moving the wall back to the left.
– Pressure on the right side is higher, pushes back
towards the left side which has a lower pressure.
Heat
•
The energy transferred from a hotter object
to a cooler one.
• Three ways it is transferred.
–
–
–
Radiation
Conduction
Convection
Radiation
Climate
• The direct transfer of energy
over long distances of empty
space.
• Moves in waves.
(Electromagnetic Waves)
• No direct contact
• Can not see it, but feel it a
heat (Infrared)
– Sunlight
– Open fire
Conduction
• Heat transfer by direct
contact of particles of
matter. (Transfer by
Touching)
• Particles bump into each
other and transfer their
energy heating them up.
– Putting your hand on a hot
stove.
Convection
• Heat transfer by the circular movement of a
fluid (liquids and gasses).
• Particles flow transferring heat energy.
• Caused by differences in density.
How Convection Works
• Density: the amount of mass in a given
volume. D=M/V
• Heated Fluids:
– Move faster and bump into other particles.
– They spread out increasing the volume.
– Density decreases
• Cooling Fluids
– Move slower
– They come together decreasing the volume.
– Density increases
Heat Transfer in the Troposphere
• Radiation, conduction and convection work
together to heat the troposphere.
• The surface absorbs solar energy.
• Air near the surface is warmed by radiation
and conduction of heat from the surface to
the air.
Heat Transfer in the Troposphere
• Convection causes most of the heating of the
troposphere.
• Convection Current–
–
–
–
–
Heated molecules have more energy.
They move faster and spread further apart.
Air becomes less dense and rises.
Cooler air is more dense and sinks.
Moves into the place of the rising air.
Heat Transfer in the Troposphere
1,2,3 Candle Diagram
Egg Demonstration
• Diagram Explanation:
• Written Explanation:
Can Demonstration
• Diagram Explanation:
• Written Explanation: