Basic Physics Question

[MSU_1978]

QED, please explain how any matter is converted to energy. I thought this only happened in nuclear reactions, not chemical reactions.

[Q.E.D]

It happens any time energy is reased. The amount is very, very small, but there is a mass different after the reaction. I’m trying to locate a cite.

[Cheesesteak]

MSU 1978, The Master Speaks

Dear Cecil:

Regarding your recent column, in which you applied the equation E=mc^2 to the digestive process: not many of us have nuclear stomachs. We get our energy from chemical reactions, not nuclear reactions–that is, unless airline food is even worse than I thought. It seems you’re a beanbrain, too! --Rob Bonney, Lanham, Maryland

PS: I really enjoy your column!

Dear Rob:

Don’t bandy words with me, you slime. Despite what many of the Teeming Millions apparently believe, E=mc^2 applies to all reactions, not just nuclear ones. Permit me to quote from Space and Time in Special Relativity by N. David Mermin, a book I read myself to sleep with every night: “A loss of mass occurs whenever internal energy (nuclear, electrical, chemical, etc.) is converted into energy of motion. Only in the nuclear case is the amount of energy so large that [it results] in an observable change in mass, but in principle E=mc^2 is as descriptive of a chemical explosive, a gasoline engine, or a flying bird [or, I might add, a flying human] as it is of a nuclear explosion.” Case closed.

[scr4]

But if the released energy (heat) stays inside the box, the weight of the box wouldn’t change. The box will get lighter only after the heat has escaped from the box to the outside environment.

[Q.E.D]

Mass interchangeability with energy stems from Einstein’s Special Relativity. This is incorporated into quantum mechanics. Simply, whereever an emission of energy takes place no matter what format, some mass must be lost. A chemical exothermic reaction emits such a tiny amount of energy, the mass loss is negligible but for nuclear reactions, it certainly is not.

From this page.

[MSU_1978]

Well, I’ll be darned. Thank you for the information, I learned something today.

[Jinx]

It’s funny how even engineers find themselves puzzled by a question about the weight of fish swimming in a fish tank, or an airplane flying in the sky. In layman’s terms, it’s action-reaction. The weight of the fish, or plane, (respectively) is supported by the water, or air (respectively)…they are not weightless…like the flour particles floating (or suspended) in the OP’s example.

Those in the physical sciences puzzled by this should first think to draw a free body diagram which might help to prove it to themselves. - Jinx