NSES Content Standard B 
Physical Science: Conservation of energy and the increase in disorder
Grades 9-12, 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.
 

 
Benchmark 4E The Physical Setting: Energy Transformations
Grades 6-8, page 85
Energy cannot be created or destroyed, but only changed from one form into another.

Benchmark 4E The Physical Setting: Energy Transformations
Grades 6-8, page 85
Heat can be transferred through materials by the collisions of atoms or across space by radiation. If the material is fluid, currents will be set up in it that aid the transfer of heat.

Benchmark 4E The Physical Setting: Energy Transformations
Grades 9-12, page 86
Whenever the amount of energy in one place or form diminishes, the amount in other places or forms increases by the same amount.