Energy Transfer and Phase Change
NS 696 V: Weather and Climate for Educators
Colorado Standard 4.2 Students know and understand the general characteristics of the
atmosphere and fundamental processes of weather.
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Analyzing the structure of, changes in, the atmosphere, and its significance for life on
earth;
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Explaining and analyzing general weather patterns by collecting, plotting, and
interpreting data;
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Describing how energy transfer within the atmosphere influences weather (the role of
conduction, radiation, convection, and heat of condensation in clouds, precipitation,
winds, and storms);
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Investigating and explaining the occurrence and effects of storms on human populations
and the environment;
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Describing and explaining factors that may influence weather and climate.
Part I
Engage: Class time 15 minutes
Utilizing the student prior knowledge of energy cycles (review if necessary)
In this activity, students begin to understand how condensation occurs on a cold surface. Place
students in small groups
Materials: on each table Metal pitcher, non-mercury thermometer, crushed ice, long spoon,
paper towels, 100ml beaker
Procedure:
1. Fill the metal pitcher halfway with warm water. Make sure water is heated to 30-40C (if
water is from the tap). Use paper towels to wipe off sides of pitcher. With the
thermometer measure the temperature of the air in the classroom and the temperature of
the water in the pitcher. Record these in your journal.
2. Fill the 100ml beaker with crushed ice, then pour the ice into the pitcher and stir the ice
with the long spoon.
3. Repeat step 2 until the water begins to appear on the outside of the pitcher. When this
occurs, measure and record the temperature of the water in the pitcher.
Explore/Analyze
Students will compare the temperature at which drops of water appeared on the outside of the
pitcher to the temperature of the air in the classroom.
Formulate a hypothesis of how you think the water appeared what kind of energy made this
happen?
Part II
Explain: Using this introduction activity we know can lead the students into the part of
describing the processes by which energy heats the troposphere.
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Objectives: what happens to the energy Earth receives from the sun?
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How is energy transferred within the troposphere?
Instruct: There are three main forms of transfer of energy that can heat our surface (define them)
radiation, convection and conduction. Energy is transferred within the troposphere by Solar (sun)
radiation which heats Earth’s surface, which in turn transfers energy to the troposphere (upward).
Energy is released by Earth’s surface in the form of infrared radiation. (explain the
electromagnetic spectrum briefly) Atmospheric gases such as water vapor, carbon dioxide, and
methane absorb infrared radiation. These greenhouse gases also reradiate some of that energy
back to earth’s surface. This transfer of energy by radiation is very efficient and is the primary
mechanism by which the troposphere is heated. The air in direct contact with Earth’s surface is
heated by conduction. Air is not a good conductor of heat, so conduction is the least significant
way heat is transferred. Warm air near the surface rises and expands and cooler, denser air sinks,
forming convection currents that move heat through the troposphere. Because in convection
some heat energy is converted to kinetic energy, convection is a less efficient way of transferring
heat. Convection cells in the atmosphere exist simultaneously on global, regional, and local
scales. Global convection cells produce high pressure in the region of 30N. Within that region,
different surfaces have different heat capacities which set up temperature and pressure
differences and smaller cells are formed. These small cells can result into local winds and other
weather conditions.
During this lecture you can demonstrate the three methods by using simple tools of a heat lamp
and having students come up to feel the heat; rubbing their hands together to feel the transfer of
energy; having hot water in a beaker and with food coloring to have a convection cell appear, and
different slides of the electromagnetic spectrum.
Part III
Extend: Have students research the specific wavelengths of infrared radiation that are absorbed
by each of the major gases in the atmosphere.
Part IV
Evaluate: Have students construct a concept map connecting the main ideas of energy flow
through the atmosphere and extend this map into how this energy affects the differences in
weather throughout a typical day (the production of storms). This can lead you into the next
lesson on cloud formations, weather patterns, fronts etc.
Lesson generated by Gina Festigitano