• 9-12: 3A/H4. Engineers use knowledge of science and technology, together with strategies of design, to solve practical problems. Scientific knowledge provides a means of estimating what the behavior of things will be even before they are made. Moreover, science often suggests new kinds of behavior that had not even been imagined before, and so leads to new technologies.

• 9-12: 4E/H1. Although the various forms of energy appear very different, each can be measured in a way that makes it possible to keep track of how much of one form is converted into another. Whenever the amount of energy in one place diminishes, the amount in other places or forms increases by the same amount.

• 9-12: 4F/H6c. The energy of waves (like any form of energy) can be changed into other forms of energy.

• 9-12: 4G/H4d. Semiconducting materials differ greatly in how well they conduct electrons, depending on the exact composition of the material.
• 9-12: 4G/H8. The motion of electrons is far more affected by electrical forces than protons are because electrons are much less massive and are outside of the nucleus.

• 6-8: 8C/M5. Energy from the sun (and the wind and water energy derived from it) is available indefinitely. Because the transfer of energy from these resources is weak and variable, systems are needed to collect and concentrate the energy.
• 9-12: 8C/H8. Sunlight is the ultimate source of most of the energy we use. The energy in fossil fuels such as oil and coal comes from energy that plants captured from the sun long ago.

• 9-12: 11A/H2. Understanding how things work and designing solutions to problems of almost any kind can be facilitated by systems analysis. In defining a system, it is important to specify its boundaries and subsystems, indicate its relation to other systems, and identify what its input and output are expected to be.

• 6-8: 11B/M4. Simulations are often useful in modeling events and processes.

• 9-12: 11C/H12. Even though a system may appear to be unchanging when viewed macroscopically, there is continual activity of the molecules in the system.

• 6-8: 11D/M3. Natural phenomena often involve sizes, durations, and speeds that are extremely small or extremely large. These phenomena may be difficult to appreciate because they involve magnitudes far outside human experience.

For teachers doing a unit on photovoltaics, this Flash animation will help students visualize what happens at the atomic scale as captured photons are converted to electric current in the solar cell. Toggle between two types of solar cells: the traditional silicon semiconductor and the newer dye-sensitized cell. Kids will see that there's more than one way to excite an electron.

• Physics First Energy Transformation Unit
• Conceptual Physics Energy Transformation Unit
• Algebra-Based Physics Energy Transformation Unit
• AP/Calculus-Based Physics Energy Transformation Unit