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Lesson Plan 2 – Day 1

Earth’s Energy Budget

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Earth’s Energy

Energy is the ability to change the surroundings

Examples: fuel for a car, ball falling from a window, electricity to turn on a light

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Budget

Budget is the amount of incoming or outgoing energy allocated to a system

Money
Time

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Equilibrium

Equilibrium is the state of balance between things

Emotional
Chemical reactions
Forces

Equilibrium means that the total amount may change over time, but the proportion in the budget parts stay fairly the same.

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Follow the Energy . . . .

SUN – EARTH Model

What in the model is the Sun?
What in the model is the Earth?

Where is the equator?
Where is the north pole?
Where are you?

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Sun emits radiation

Earth intercepts

sunlight

Input = Sunlight on one side of Earth

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Sunlight is Energy

Sunlight comes in a range of SHORT wavelengths called visible light

Use this slide to introduce the idea that light can be divided into wave lengths.

Goal: Students will see that the rope can move in different wave lengths. This demo will be repeated on day 2 of lesson 2.

Demonstration:

With a 5’ long rope, have one student hold one end while the teacher holds the other end. Rotate the rope to get a wave pattern. Have students count the number of waves. Make sure everyone is counting the same thing. Now increase the amount of energy and there should be more waves. Ask students to compare the amount of energy that is put into the rope if there are are more waves (shorter) or less waves (longer). They should see that you have to put in more energy to create more shorter waves. Explain that with sunlight the waves are short and in the visible range so that we can see sunlight.

This demonstration could be done in small groups, with shorter ropes.

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Once the sunlight reaches the Earth’s surface, what happens?

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Reflected or Absorbed

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Follow the Energy

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Albedo = Reflection

How much is reflected?
Scale is 0-1

White =1,

High reflectivity

Black = 0

Low reflectivity

What do you think? High or low albedo?

Grass
Ice
Rocks
Asphalt
Concrete

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Albedo = Reflection

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Optional Video

http://www.youtube.com/watch?v=9UJKVa2ClCU&feature=related
Begin at 1:50. Researcher out on the ice, measuring albedo.

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CLOUDS

Clouds reflect sunlight and need to be included in the energy budget

Low thick clouds = high reflection, cools the surface
High thin clouds = lower reflection and other things (next class), warms the surface

Clouds are part of the energy budget. They are important in both incoming radiation because they reflect some incoming radiation. And as will be discussed on day 2 of this lesson, clouds also absorb the long wave radiation emitted by Earth.

The goal of this slide is for students to include clouds in their understanding of what impacts the energy budget.

Because a cloud usually has a higher albedo than the surface beneath it, the cloud reflects more shortwave radiation back to space than the surface would in the absence of the cloud, thus leaving less solar energy available to heat the surface and atmosphere. Hence, this "cloud albedo forcing," taken by itself, tends to cause a cooling or "negative forcing" of the Earth's climate.

The study of clouds, where they occur, and their characteristics, play a key role in the understanding of climate change. Low, thick clouds primarily reflect solar radiation and cool the surface of the Earth. High, thin clouds primarily transmit incoming solar radiation; at the same time, they trap some of the outgoing infrared radiation emitted by the Earth and radiate it back downward, thereby warming the surface of the Earth. Whether a given cloud will heat or cool the surface depends on several factors, including the cloud's altitude, its size, and the make-up of the particles that form the cloud. The balance between the cooling and warming actions of clouds is very close although, overall, averaging the effects of all the clouds around the globe, cooling predominates. http://earthobservatory.nasa.gov/Features/Clouds/

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Sun emits radiation

Earth intercepts

sunlight

Input = Sunlight on one side of Earth

30% is reflected

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What happens to the energy that enters the Earth system?

Concept Map – additions

Sun or Sunlight
Earth
Energy Budget
Albedo

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End of Day

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What types of areas of Earth have �- a high albedo? �- a low albedo?��(think urban, farmland, desert, etc.)

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Earth’s albedo

Collected by NASA satellite and averaged. Does not include the ocean and no data for white areas.

Optional Slide:

The colors in this image emphasize the albedo over the Earth’s land surfaces, ranging from 0.0 to 0.4. Areas colored red show the brightest, most reflective regions; yellows and greens are intermediate values; and blues and violets show relatively dark surfaces. White indicates where no data were available, and no albedo data are provided over the oceans.

Remind student of what they learned about the distribution of sunlight with the Sun-Earth model. Sunlight does not reach everywhere equally.

This image was produced using data composited over a 16-day period, from April 7-22, 2002.

A new sensor aboard NASA’s TerraA new sensor aboard NASA’s Terra satellite is now collecting the most detailed and accurate measurements ever made of how much sunlight the Earth’s surface reflects back up into the atmosphere. By quantifying precisely our planet’s reflectivity, or albedo, the Moderate Resolution Imaging Spectroradiometer (MODIS) is helping scientists better understand and predict how various surface features influence both short-term weather patterns as well as longer-term climate trends.

A low albedo mean that lots of energy is absorbed and only some is reflected. A high albedo like snow and ice means little absorption and lots of reflection. The most northern and southern areas are shown in white which means no data were available.

Ask student - What would you predict for Antarctica? What would you predict about the temperature from this data? Does this give us the whole picture of climate? What about weather? What might cause a change in albedo in one location?