A Scientific Discussion

The term destroyed or created in this case is the process of creating something from nothing or turning something into nothing. The Laws of Conservation are basically stating that there is a constant sum of matter and energy in our Universe. It is impossible to add to this sum or subtract from this sum.

The entire discipline of Chemistry is built around and depends on the Law of Conservation of Matter and Energy. I sure hope there aren't professors out there telling their students it is an old and disproven law.

Jam it back in, in the dark.

Originally Posted by YeOldeButchere

Matter can be created or destroyed, matter/anti-matter annihilation gives a fairly definite answer.

Nope, matter/anti-matter annihilation is just the process of turning all matter of a system into energy. Nothing is being removed from existence. It's just a transfer of a matter state to an energy state.

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But there are cases where it's slightly more difficult to answer. Nuclear fission/fusion is one example. Assume you were to take 2 protons and 2 neutrons, and mesure their mass, for this example let's say each particle weighs 1 (no unit), so the total mass is 4. Now, fuse them together to form an helium nucleus. Surely you'd expect that the nucleus would weigh 4, but it won't be the case. The nucleus will weigh slightly less than 4, with the difference between 4 and the actual mass being tranformed in energy in accordance to E=mc^2. But the number of particles is still the same! The only thing that has changed is the mass. Can we say that matter was destroyed in this case?

Nope, some of the matter was converted into energy. It wasn't lost. Under the right conditions that energy can be reclaimed into matter again thus that matter hasn't been destroyed. Its state has only been changed. This is the Law of Conservation of Matter and Energy. I think some of you are reading way too far into what the law states. The sum of energy and matter of what you put into something results in a equal matter and energy sum.

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The answer is essentially a matter (pun intended) of what definition of matter you use, and it's pretty much the same for a number of other problems. Creation of particle/antiparticle pairs? Well, it depends on whether or not you consider said particles to be matter or not. Creation then destruction of particles through the Heisenberg uncertainty principle when applied to time and energy? Same thing, it depends of what you consider matter to be.

If it is not matter, its energy. If it is not energy it is matter. These are the only two states of existence in our Universe. There are no in between or ambiguous states. There is only one single definition of matter. If your 'object' doesn't fall under the matter category, then it is in an energy state.

Heisenberg uncertainty principle also deals with the wave/matter duality of electrons and the fact that we have no measurable way to detect the moment of electrons. We can only guess their probable position based on observable/measurable events. It has nothing to do with the creation and destruction of particles.

There's nowhere I can't reach.

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Depends on if you consider things like photons, W bosons, and Z bosons (mediate EM, weak nuclear, and strong nuclear respectively) to be matter.

Photons exist in a dual state which exhibits matter or energy properties depending on their current interaction state. They are either or the other at any given time thus they can be either matter or energy.

As for the rests mentioned, those are carrier particles. In simple terms they do not exist, rather they are representations of a concept much like our number system.

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And for that matter, what the hell are matter and mass, anyway?

Isn't this first year science? Matter is anything that takes up space. Mass is the quantified measurement of matter.

This thing is sticky, and I don't like it. I don't appreciate it.

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True, and I never said such wasn't the case. I said that matter was destroyed. Whatever it becomes afterwards doesn't make it any less true; that matter has stopped to exist as matter.

Ah I think I understand the underlying problem here. It's like saying when ice metals and becomes water, the ice no longer exists. But we know this isn't true. Rather the ice exists just in a different matter state. Matter and energy share a similar concept. The problem is the Law of Conservation of Matter and Energy isn't exactly saying matter cannot be created or destroyed. The definition we get in most text books is just a simplification of the concept.

A better way to express the Law is to say something like "The sum of what you put in will always equal the sum of what you get." It's saying that in a perfectly closed reaction nothing is ever gained or lost, eg. created or destroyed.

Does that make sense?

I am a dolphin, do you want me on your body?