Whats the difference....

 

I have two examples where it is used most often.

 

1) The very early universe consisted of Pure Energy.

2) Matter and anti-matter anihilate each other into Pure Energy.

Both of those are false statements, as there is no such thing as "pure energy." It is a property of things, not a thing itself. When matter and antimatter meet, they are "annihilated," and new particles are created, like high-energy photons. If the term "pure energy" is used, electromagnetic radiation is probably what is intended.