Can we convert energy to mass?

[hanii]

Can we convert energy to mass??

hi guys...,
I'm new to this site. so please just spare me if I've done something wrong..coming to the topic we all know that mass can be converted to energy..but can we convert energy to mass according to the equation e=m*(c^2)..??

 

[daveb]

I'm not a particle physicist, but I imagine the man-made synthesis of transuranic elements via particle accelerators is technically turning energy into mass.

 

[Nikitin]

Scientists are creating new elements all the time. These new elements have more mass per nucleon than the "older" ones (like element nr. 133 has more mass per nucleon than nr. 132). Argh, please somebody who knows English properly explain this?

Anyway, this means that scientists are turning energy into mass.

EDIT: Heck, wouldn't making chemical reactions where the enthalpy change is positive mean the same thing? I.e. for example 2H2 and O2 have more mass than 2H2O? I seem to recall the reason, at least partially, that energy is released when H2 and O2 react being mass is liberated into energy?

 

[Drakkith]

Yes! When we collide two electrons together at very high energies the resulting mass of created particles are far beyond the original rest masses of the two electrons! The same thing happens for other particles too.

Edit:As Dalespam points out below, it is more correct to say that MATTER can be converted to energy and vice versa, as energy always has mass.

 

[Dale]

We don't convert energy to mass, energy already has mass without any conversion needed. However, we can convert energy to matter which is probably what you were really asking.

 

[Silverhill]

Scientists are creating new elements all the time. These new elements have more mass per nucleon than the "older" ones (like element nr. 133 has more mass per nucleon than nr. 132). Argh, please somebody who knows English properly explain this?

Your English, and your explanation, are fine.

Heck, wouldn't making chemical reactions where the enthalpy change is positive mean the same thing? I.e. for example 2H₂ and O₂ have more mass than 2H₂O? I seem to recall the reason, at least partially, that energy is released when H₂ and O₂ react being mass is liberated into energy?

Indeed. H₂ and O₂ have a tiny bit more mass than they do when combined. The energy release is about 285 kJ/mol, or about 3 ng/mol.

 

[Drakkith]

We don't convert energy to mass, energy already has mass without any conversion needed. However, we can convert energy to matter which is probably what you were really asking.

Exactly. E=MC^2 is NOT saying that mass can be converted to energy and vice versa, it is saying that all energy has an accompanying amount of mass. When you add or remove energy from a system you also add or remove mass as well.

 

[hanii]

Exactly. E=MC^2 is NOT saying that mass can be converted to energy and vice versa, it is saying that all energy has an accompanying amount of mass. When you add or remove energy from a system you also add or remove mass as well.

you meant to say that when i push an object there is an energy imparted to it..and this energy alters its mass...as energy has an accompanying amount of mass

 

[Dadface]

I'm surprised that nobody has mentioned "pair production" yet.Try googling.

 

[Nikitin]

you meant to say that when i push an object there is an energy imparted to it..and this energy alters its mass...as energy has an accompanying amount of mass

no, energy is not transformed into mass in your scenario. You get energy to push the object from chemical reactions inside your muscles. After a while due to friction the object which you had pushed will have transformed all its kinetic energy into heat

 

[Dale]

you meant to say that when i push an object there is an energy imparted to it..and this energy alters its mass...as energy has an accompanying amount of mass

Yes, exactly.

no, energy is not transformed into mass in your scenario. You get energy to push the object from chemical reactions inside your muscles. After a while due to friction the object which you had pushed will have transformed all its kinetic energy into heat

And heat has mass. Energy has mass, it does not need to be "transformed into" mass.

 

[treehouse]

Earlier today I was wondering if it were possible to generate protons from electrons, positrons, neutrinos and/or anti-neutrinos using a particle accelerator.

 

[Drakkith]

Earlier today I was wondering if it were possible to generate protons from electrons, positrons, neutrinos and/or anti-neutrinos using a particle accelerator.

I believe this is all possible and regularly occurs at most modern accelerators/colliders. It isn't controlled, as we cannot simply say "I want 3 protons and that's it from this collision". An assortment of different particles are created.

 

[Nikitin]

dalsespam, I learned from my teacher that energy and mass are two sides of the same coin, so to speak. I'm not sure what you mean? Energy and mass regularly change forms, don't they?

 

[Dale]

dalsespam, I learned from my teacher that energy and mass are two sides of the same coin, so to speak. I'm not sure what you mean? Energy and mass regularly change forms, don't they?

Energy certainly regularly changes to other forms of energy (e.g. kinetic energy to electrical energy). I don't know of any "forms" of mass.

Energy is the capacity of a system to do work. Mass is a measure of the amount of inertia of a system. They are both properties of systems, they are not things in and of themselves. A system can have more than one property, for example it can be blue and hot. Similarly, a system can have both inertia (mass) and the capacity to do work (energy). E=mc² is not about "changing" energy into mass. It is about the fact that a system with energy has a certain amount of inertia, and a system with mass can do a certain amount of work.

 

[Nikitin]

I meant that energy can change form into mass and vice versa.

Well, to be hyper-formal: energy/mass can change its appearance

:P

 

[Dale]

I think I have said this 3 times now in this one thread. Energy does not change form into mass, it already has mass to begin with even without changing form.

Mass is not a form of energy.

You can, however, produce matter given sufficient energy in a particle collider. In such a case you would get a transformation of energy from e.g. kinetic energy to rest energy. But the mass would be unchanged.

 

[Drakkith]

I meant that energy can change form into mass and vice versa.

Well, to be hyper-formal: energy/mass can change its appearance

:P

This is a very widespread misconception. Mass and Energy NEVER change into one another. It isn't possible. As Dalespam said, Mass and Energy aren't "things" in themselves. Energy is the capacity to do work. It describes the interactions between objects. Adding energy into a system increases its mass. In a chemical or nuclear reaction the released energy has mass and removes that mass from the reaction products in the form of heat and light.

 

[cragar]

What kind of mass would we say a photon has. Aren't there like 3 different types of masses.

 

[Drakkith]

Photons don't have rest mass, they have momentum. According to GR the effect is identical concerning the effects of gravity, as photons are affected by gravity and also generate their own gravitational field. When the photon is absorbed the momentum is transferred to the object, which increases its mass. In effect the mass has been transferred from the object emitting the photon to the object absorbing it.

 

[cragar]

so a photon has an effective mass .

 

[Drakkith]

so a photon has an effective mass .

I think it is more accurate to say that a photon has no mass, but has momentum which can transfer mass.
Edit: I think it really depends on your definition of mass.

 

[cragar]

ok , I was just reading Dalespams post and he said the mass would be unchanged but we could transform energy into matter.

 

[Drakkith]

ok , I was just reading Dalespams post and he said the mass would be unchanged but we could transform energy into matter.

That is correct.

 

[cragar]

ok thanks, just making sure

 

[Dale]

What kind of mass would we say a photon has. Aren't there like 3 different types of masses.

A photon has "relativistic mass", but not "invariant mass". Most physicists don't use relativistic mass any more, but it is still found in a lot of textbooks and many historical papers, so it is good to know what it is.

ok , I was just reading Dalespams post and he said the mass would be unchanged but we could transform energy into matter.

I was actually referring to the invariant mass of the system. This can be much higher than the rest masses of the individual particles that make up the system, actually that is the whole purpose of a particle collider. As an example, a 1 MeV photon moving to the right it has 0 invariant mass, and a 1 MeV photon moving to the left also has 0 invariant mass, but a system of a 1 MeV photon moving to the right and a 1 MeV photon moving to the left has an invariant mass of 2 MeV/c². The invariant mass is given by m²c² = E²/c² - p². For a system with no overall momentum this reduces to the familiar E = mc².

 

[hanii]

Yes, exactly.

And heat has mass. Energy has mass, it does not need to be "transformed into" mass.

hey hey...heat has mass??

 

[hanii]

if energy has mass ...can we measure it practically without imparting to any mass??

 

[Dadface]

hey hey...heat has mass??

It was one of Einsteins favourite illustrations to state that an object when hot is more massive than the same object when cold.

 

[Drakkith]

if energy has mass ...can we measure it practically without imparting to any mass??

No, any measurement requires an interaction of forces, which will alter the energy of the systems involved in some way. But you can calculate it.

 

[hanii]

It was one of Einsteins favourite illustrations to state that an object when hot is more massive than the same object when cold.

but hot water is lighter than cold water...!

 

[Dadface]

but hot water is lighter than cold water...!

Are you confusing mass with density?

 

[treehouse]

Mass and energy are just metrics applied to systems; unlike Transformers they are not actual objects. E=mc^2 says that the energy in a system is equal to the mass of a system times the speed of light in a vacuum. This implies that adding energy to a system increases its mass; its 'rest mass' is the mass it has when it has no energy. Sometimes rest mass is created by particle accelerators or positron emission; because of the law of conversation of mass, it is assumed that the rest mass created is equal to the mass of the energy that is consumed by its creation.

The nuclear reactions inside stars cause them to emit cosmic rays including protons. Those protons (hydrogen nuclei) can be used as fuel for nuclear fusion. The fused nuclei (or just the protons emitted by stars) can drift into a forming star, becoming fuel for that star's nuclear reactions.

 

[Drakkith]

Mass and energy are just metrics applied to systems; unlike Transformers they are not actual objects. E=mc^2 says that the energy in a system is equal to the mass of a system times the speed of light in a vacuum.

Mass is a fundamental property while energy is a description of the interaction of systems via work. While i agree that mass and energy themselves are not "objects", all objects have mass and energy.

The nuclear reactions inside stars cause them to emit cosmic rays including protons. Those protons (hydrogen nuclei) can be used as fuel for nuclear fusion. The fused nuclei (or just the protons emitted by stars) can drift into a forming star, becoming fuel for that star's nuclear reactions.

This is...kind of correct? The nuclear reactions inside stars release energy and neutrinos, but the reactions themselves do not release "cosmic rays" in the form of protons or electrons. The solor wind is composed of charged particles such as electrons and protons, but these are ejected from the outer atmosphere of the sun, not the core where the fusion is taking place. Also, the unused Hydrogen can indeed form other stars, and it is our current view that the Sun was created when a nebula, composed of hydrogen and other elements from previous stars, collapsed in on itself.