Alaska Science Performance Standard L4/A8c

	Alaska Science Key Element A8c A student who meets the content standard should understand the scientific principles and models that state that whenever there is a transformation of energy, some energy is spent in ways that make it unavailable for use (Energy Transformations).

Performance Standard Level 4, Ages 15–18

Students explain entropy and its affect on energy availability.

Sample Assessment Ideas

“It is easier to mess things up than to put them in order.” This is often used as a way to show the idea of entropy as something happening in all the environment. Choose three examples from your home or community that seem to demonstrate this quote and explain why they do so.
Students draw posters or diagrams and use them to explain all the energy and entropy changes happening in a snowmobile, including within the engine, and why all the energy from burning the fuel in the engine doesn’t go into driving the snowmobile forward. What is becoming less ordered as the snowmobile operates?

Expanded Sample Assessment Idea

Expanded Sample Assessment Idea

Students observe the following changes themselves or as demonstrations, and explain why they happen with special reference to energy and entropy changes.

Procedure Students will: Observe systems before and after a change has occurred. Suggested systems include: Leave a saturated sugar solution on the window ledge; sugar crystals appear in a while Stir solid ammonium thiocyanate crystals with barium hydroxide crystals Hit a small rubber ball many times against a wall causes the ball to heat up. Mix ammonium sulfate crystals and water. Activate a drug store or athletic department “cold pack” or “hot pack”. Carefully record observations. Measure heat effects using a thermometer (before and after); record and tabulate results. Build models to demonstrate what happens in the change. Use the model as part of an oral presentation on what happens. Reflection and Revision Find one clear example of a similar change that demonstrates an entropy effect in the community/environment and create a poster to explain this to a parent group.	Levels of Performance
	Stage 4	Student work is complete, and shows clear understanding of kinetic and positional energy (entropy) and how these relate to processes and change. Measurements, data, observations, and inferences are detailed and accurate. An accurate model and poster are created, and used to effectively explain energy and entropy interactions.
	Stage 3	Student work is mostly complete, and shows understanding of kinetic and positional energy (entropy) and how these relate to processes and change. Measurements, data, observations, and inferences are appropriate, although they may contain minor errors or omissions. A reasonable model and poster are created, and used to describe energy and entropy interactions.
	Stage 2	Student work may be incomplete, and shows limited understanding of kinetic or positional energy (entropy) or how they relate to processes and change. Measurements, data, observations, and inferences are incomplete, incorrect or lack detail and logical reasoning. Model and poster may show evidence of skilled craftsmanship but cannot be used to describe energy interactions.
	Stage 1	Student work is mostly incomplete, and shows little or no understanding of energy or entropy. Data and observations are incomplete or incorrectly recorded. Model and poster may show evidence of skilled craftsmanship but are inaccurate and do not support explanations.

Standards Cross-References
( Alaska Department of Education & Early Development Standards)

National Science Education Standards

Heat consists of random motion and the vibrations of atoms, molecules, and ions. The higher the temperature, the greater the atomic or molecular motion. (Page 180)

The total energy of the Universe is constant. Energy can be transferred by collisions in chemical and nuclear reactions, by light waves and other radiations, and in many other ways. However, it can never be destroyed. As these transfers occur, the matter involved becomes steadily less ordered. (Page 180)

Everything tends to become less organized and less orderly over time. Thus, in all energy transfers, the overall effect is that the energy is spread out uniformly. Examples are the transfer of energy from hotter to cooler objects by conduction, radiation, or convection and the warming of our surroundings when we burn fuels. (Page 180)

Benchmarks

Heat energy in a material consists of the disordered motions of its atoms or molecules. In any interactions of atoms or molecules, the statistical odds are that they will end up with less order than they began—that is, with the heat energy spread out more evenly. With large numbers of atoms and molecules, the greater disorder is almost certain. (Page 86)

Transformations of energy usually produce some energy in the form of heat, which spreads around by radiation or conduction into cooler places. Although just as much total energy remains, its being spread out more evenly means less can be done with it. (Page 86)

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