NSES Content Standard B 
Physical Science: Transfer of energy
Grades 5-8, page 155

Electrical circuits provide a means of transferring electrical energy when heat, light, sound, and chemical changes are produced.

Benchmark 4E The Physical Setting: Energy Transformations
Grades 6-8, page 85
Most of what goes on in the universe--from exploding stars and biological growth to the operation of machines and the motion of people--involves some form of energy being transformed into another. Energy in the form of heat is almost always one of the products of an energy transformation.

Benchmark 8C The Designed World: Energy Sources and Use
Grades 6-8, page 194
Electrical energy can be produced from a variety of energy sources and can be transformed into almost any other form of energy. Moreover, electricity is used to distribute energy quickly and conveniently to distant locations.