Energy Exercise B1
The goal of this exercise is for you to be able to indentify types of energy and energy
transformations associated with movement and/or change of matter. To accomplish this
goal we are going to draw analogies between energy flow and transformation in two realworld situations.
The Flood
Water that evaporated from the oceans was carried high into the atmosphere by wind
currents. As the air rose over the Rocky Mountains, it cooled and the water condensed
to form dark clouds. By late afternoon, lightening flashed and along with the roar of
thunder came a heavy down pour. Water rushed over bare rock and thin soil to small
stream leading to a high mountain lake. The lake formed behind a pile of rocks from a
landslide that blocked the valley hundreds of years ago.
The high mountain lake, 12,000 feet above sea level, is accessible only by a steep trail
18 miles away from the nearest trailhead. Few people are willing to make the trek, so
the cutthroat fish population was thriving until a bear, hunting for fish, kick loose one
large rock in the pile of rocks holding the water in the lake. Water came rushing through
the hole where the rock was lodged and soon the rocks and water that had been
captured behind it were rushing down the mountain slope toward the village below.
People heard the roar in time to climb up the sides of the valley. They managed to
escape without harm but all the buildings in the village were destroyed.
Mary’s Morning Coffee
Tree rings show the annual growth of trees. During the warm months, trees draw water
from the ground and carbon dioxide from the atmosphere to grow by the process of
photosynthesis. Plants release energy during respiration and use the released energy,
in part, to build more complex molecules and grow. Some trees in the Rocky Mountain
National Forest grew to enormous heights before the infestation of bark beetles
destroyed it and most of the surrounding trees. Pete had a permit to cut down the dead
pines, haul them away and sell the wood for firewood. Mary, who lived in a cabin high
in the mountains, bought ten cords of the wood from Pete for $1000.00. Pete drove his
truck up and down the mountain several times to get all the wood to Mary’s cabin. Mary
used the wood to heat her cabin and for cooking on a wood burning stove.
Mary enjoyed her quiet existence and liked to muse about connections as she struck a
match to start her wood-burning stove, made her morning coffee and watched the
sunrise.
Part 1. Alignment and inference
There are aspects of energy flow and transformation described in the story about the
flood that correspond to aspects of the story about Mary’s coffee. For each component
listed below about the flood (Table 1), please list a corresponding component about
Mary’s coffee. If a component of the flood has no corresponding component in Mary’s
coffee, write NC (no correspondence) in the Mary’s Morning Coffee column. Note that
you can use components more than once. In other words, a component in either column
may have more than one correspondence with a component in the other column.
In addition to listing the corresponding components, in the third column list the
Relationship between the components. The first row in the table has been competed
for you as an example.
Table 1. Relationships between The Flood and Mary’s Morning Coffee
The Flood
Mary’s Morning Coffee
Relationship
Evaporation by solar
Photosynthesis using solar
Solar energy is a cause
radiation
radiation
of the reaction
Wind currents driven by heat
from solar radiation
Water in a mountain lake
Bear kicked loose a rock to
start the flood
Stream carries water and
rock to village
Destroying buildings
Table 1. Relationships between The Flood and Mary’s Morning Coffee –KEY
The Flood
Mary’s Morning Coffee
Relationship
Evaporation by solar
Photosynthesis using solar
Solar energy is a cause
radiation
radiation
of the reaction
Wind currents driven by heat
from solar radiation
Water in a mountain lake
Trees
Both contain stored
energy, water has
gravitational potential
energy and Trees have
chemical potential
energy.
Bear kicked loose a rock to
Mary lights the match
Flood converts
start the flood
gravitational potential
into kinetic; match
converts chemical
potential into heat and
chemical products
Stream carries water and
Pete drives the wood up the
Stream moves water
rock to village
mountain
and rock through
gravitational kinetic
energy; pete drives
wood up the mountain
by converting chemical
potential into kinetic
energy
Destroying buildings
Beetle destroying trees?
Influx of one thing that
makes another thing
unusable?
Part 2. Finding the Limits of an Analogy & Inference Evaluation
While analogies are very useful, they all have their limits. In this case, we want to
highlight some components that are different between the Flood and Mary’s Morning
Coffee.
There are components of the Flood that do not properly correspond to components of
the Mary’s Morning Coffee. Note that there can be aspects of components that both
match and mismatch. For example, chemical potential and gravitational potential match
in the sense that they are both forms of potential energy and they mismatch in the sense
that one is chemical and the other is gravitational. Each pair listed in Table 2 mismatch
in one or more ways. Complete the table by describing the differences
Table 2. Differences between The Flood and Mary’s Morning Coffee
The Flood
Mary’s Morning Coffee
Why are they different
Condensation
Photosynthesis
Condensation releases
energy, photosynthesis
stores energy.
Rain falls on the mountain
Trees grow
The flood flows down hill
Mary strikes a match to light
the fire
Table 2. Differences between The Flood and Mary’s Morning Coffee - KEY
The Flood
Mary’s Morning Coffee
Why are they different
Condensation
Photosynthesis
Condensation releases
energy, photosynthesis
stores energy.
Rain falls on the mountain
Trees grow
Rainfall is converting
energy (gravitational
potential energy into
kinetic); trees growing
are converting matter
(gas and liquid, into
solid)
The flood flows down hill
Mary strikes a match to light
the fire
Water flowing is
converting gravitational
potential energy;
lighting a fire converts
chemical potential
energy
We often use analogies to draw inferences. Can we infer that the same amount of
energy used by the flood to flatten a village would be used during a fire to burn it to the
ground?
Part 3: Abstraction & Redescription of the domains
When components of two domains are analogous a common principle can be used to
describe both. Note that some of these common principles may have been described in
Table 1.
For every corresponding pair of components in Table 3, use a single word or phrase that
can be used to describe the common relation, role or principle. If there is no
correspondence, write NP in the right- hand column.
Table 3. Describing the Common Relation/Principle
Flood
Mary’s coffee
Common principle
Water evaporates
Trees photosynthesize
Solar energy is used
Water condenses
Tress respire
Water in lake
Chemical bonds in wood
Water flows down hill
Wood burns
Village is destroyed
Mary makes coffee
Table 3. Describing the Common Relation/Principle - KEY
Flood
Mary’s coffee
Common principle
Water evaporates
Trees photosynthesize
Solar energy is used
Water condenses
Tress respire
Energy is released or
used
Water in lake
Chemical bonds in wood
Energy is stored.
Water flows down hill
Wood burns
Energy is released.
Village is destroyed
Mary makes coffee
??
4. Assessment – Below are two possible questions. We would probably use only one.
1. How, if at all, would higher global temperatures change the chemical and/or gravitational
energy in the water cycle?
If temperatures were higher there would be a direct impact on chemical energy because chemical
potential energy is directly related to the temperature of a system. With higher temperatures,
more water would evaporate so the size of the atmosphere reservoir would increase. Also, more
glaciers would melt, so the size of that reservoir would decrease.
There would also be an increase in gravitational potential energy because warmer air could rise
higher. Therefore, water droplets would have higher gravitational potential energy.
2. Complete the box and arrow diagram below by writing chemical, gravitational or both in the
empty boxes. These boxes represent the energy that causes movement or change from one
reservoir to another.
Answer