The first two elementary benchmarks were combined. This is also true for the original high school benchmark about conservation of energy. The idea that energy is conserved is contained in several other benchmarks, where it is used to understand energy transformations. The high school benchmark about density was moved to middle school. A benchmark about simple circuits has been added to the elementary level, while the benchmark on static electricity was deleted.
Static electricity is addressed in one of the middle school force and motion benchmarks.
Other electricity benchmarks have been reworded to make them more consistent with national standards and more developmentally appropriate. Benchmarks about magnetism were moved to the force and motion benchmarks, since they are more about moving objects than about energy. The high school benchmark about heat transfer was moved to PCM, because it is more about explaining the changes in matter brought about by heat transfer than simply differentiating between conduction, convection, and radiation. However, it should be part of the technology education curriculum at the elementary level. Einstein's equation has always been in the essay that accompanies this benchmark, but it had been left out of the original Key Concepts.