# When I get a text message on my mobile phone does it become slightly heavier?
**URL:** https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115
**Category:** Factual Questions
**Created:** [June 13, 2004, 1:58pm UTC](https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115 "2004-06-13T13:58:59Z")
**Posts on this page:** 15
**Page:** 1
### Author:  [@gcoochy](https://boards.straightdope.com/u/gcoochy)
#### Post date: [June 13, 2004, 1:58pm UTC](https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115/1 "2004-06-13T13:58:59Z")
When I get a text message on my mobile phone does it become slightly heavier?
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### Author:  [@Aeschines](https://boards.straightdope.com/u/Aeschines)
#### Post date: [June 13, 2004, 2:15pm UTC](https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115/2 "2004-06-13T14:15:03Z")
No, it doesn’t.
Your message will be stored on a memory chip. The mass of this chip will not change appreciably whether electricity is running through it or not.
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### Author:  [@Dr.Lao](https://boards.straightdope.com/u/Dr.Lao)
#### Post date: [June 13, 2004, 2:22pm UTC](https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115/3 "2004-06-13T14:22:40Z")
The same idea was addressed by the Straight Dope Science Advisory Board: [If I remove data from my hard drive, why doesn’t it weigh less?](http://www.straightdope.com/mailbag/mmemory.html)
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### Author:  [@scr4](https://boards.straightdope.com/u/scr4)
#### Post date: [June 13, 2004, 4:24pm UTC](https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115/4 "2004-06-13T16:24:39Z")
It becomes slightly lighter. It takes energy to receive and process the message, which comes out of the battery. Mass is energy, so less energy = less mass. Unless there is some gas exchange with the atmosphere - but cell phone batteries are sealed, I believe.
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### Author:  [@Aeschines](https://boards.straightdope.com/u/Aeschines)
#### Post date: [June 13, 2004, 4:37pm UTC](https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115/5 "2004-06-13T16:37:00Z")
> [@scr4](#):
>
> It becomes slightly lighter.
Oh come now. There will not be even a picogram of mass difference between a phone loaded with electricity and one that is completely dead.
An electron is, what? 1/1800 the mass of a proton, right? A spec of dust on the phone would weigh more than the difference in electrons.
Correct me if I’m wrong.
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### Author:  [@Dog80](https://boards.straightdope.com/u/Dog80)
#### Post date: [June 13, 2004, 4:48pm UTC](https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115/6 "2004-06-13T16:48:11Z")
> [@scr4](#):
>
> It becomes slightly lighter. It takes energy to receive and process the message, which comes out of the battery. Mass is energy, so less energy = less mass. Unless there is some gas exchange with the atmosphere - but cell phone batteries are sealed, I believe.
No! The battery’s mass remains the same.
A good analogy for the battery is a spring. If you put a spring under a heavy object so it is compressed, then the spring has energy stored in it. But the spring’s mass is always the same.
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### Author:  [@Dog80](https://boards.straightdope.com/u/Dog80)
#### Post date: [June 13, 2004, 4:50pm UTC](https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115/7 "2004-06-13T16:50:56Z")
> [@Aeschines](#):
>
> Oh come now. There will not be even a picogram of mass difference between a phone loaded with electricity and one that is completely dead.
>
> An electron is, what? 1/1800 the mass of a proton, right? A spec of dust on the phone would weigh more than the difference in electrons.
>
> Correct me if I’m wrong.
No, I believe that the number of electrons remains more-or-less the same. The difference is that they have gone from the negative part of the battery to the positive. When you recharge a battery you move those electrons back to the negative part, much like loading a spring.
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### Author:  [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)
#### Post date: [June 13, 2004, 4:51pm UTC](https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115/8 "2004-06-13T16:51:43Z")
> [@Dog80](#):
>
> But the spring’s mass is always the same.
No, it isn’t. You and **Aeschines** are both forgetting about e=mc[sup]2[/sup]. This equation does not just apply to nuclear reactions, but to anything where energy is stored and released, including batteries and springs. The difference may not be measurable with current technology, but it is real and calculable.
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### Author:  [@Aeschines](https://boards.straightdope.com/u/Aeschines)
#### Post date: [June 13, 2004, 4:59pm UTC](https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115/9 "2004-06-13T16:59:54Z")
> [@Q.E.D.](#):
>
> No, it isn’t. You and **Aeschines** are both forgetting about e=mc[sup]2[/sup]. This equation does not just apply to nuclear reactions, but to anything where energy is stored and released, including batteries and springs. The difference may not be measurable with current technology, but it is real and calculable.
Not I. I recognize that the phone’s using electricity causes it to lose mass.
But, assuming the OP is _really_ serious about the question, the mass is so infintessimally small that it is irrelevent.
E=mc[sup]2[/sup] also tells us that even a single atom converted 100% into energy would result in a very large quantity of energy. Contrariwise, you can use enormous amounts of energy without even removing an atom’s worth of mass.
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### Author:  [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)
#### Post date: [June 13, 2004, 5:14pm UTC](https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115/10 "2004-06-13T17:14:01Z")
> [@Aeschines](#):
>
> E=mc[sup]2[/sup] also tells us that even a single atom converted 100% into energy would result in a very large quantity of energy.
Not really. Let’s tak a carbon-12 atom, for instance. The 12 means that one mole of C-12 will mass 12 grams, or .012 kg. Since there are 6.022 x 10[sup]23[/sup] atoms per mole, one atom masses 1.99 x 10[sup]-26[/sup] kg. If we plug that into e=mc[sup]2[/sup], we get e=1.99 x 10[sup]-26[/sup] [sup].[/sup] (3.00 x 10[sup]9[/sup])[sup]2[/sup] = 1.79 x 10[sup]-9[/sup] joules. That’s pretty small. But then, so is an atom.
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### Author:  [@MrFantsyPants](https://boards.straightdope.com/u/MrFantsyPants)
#### Post date: [June 13, 2004, 5:16pm UTC](https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115/11 "2004-06-13T17:16:32Z")
> [@Q.E.D.](#):
>
> No, it isn’t. You and **Aeschines** are both forgetting about e=mc[sup]2[/sup]. This equation does not just apply to nuclear reactions, but to anything where energy is stored and released, including batteries and springs. The difference may not be measurable with current technology, but it is real and calculable.
I think you’re wrong here. Admittedly, I dropped out two years into my physics degree, so maybe they hadn’t gotten to that part.
Mass is not energy and energy is not mass. They are interchangeable according to the equation e=mc[sup]2[/sup], but only in nuclear reactions. Energy released from a battery is a conversion from chemical energy to electrical, then to mechanical or heat or light energy. No electrons are gained or lost.
This is my understanding, but if anyone’s got a cite, I’ll admit defeat.
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### Author:  [@scr4](https://boards.straightdope.com/u/scr4)
#### Post date: [June 13, 2004, 5:17pm UTC](https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115/12 "2004-06-13T17:17:24Z")
> [@Aeschines](#):
>
> Oh come now. There will not be even a picogram of mass difference between a phone loaded with electricity and one that is completely dead.
Hey, I never said there would be a _measurable_ difference. But according to my calculation, a 6V 1200 mAh battery gains about 300 picograms when fully charged.
> [@](#):
>
> E=mc[sup]2[/sup] also tells us that even a single atom converted 100% into energy would result in a very large quantity of energy. Contrariwise, you can use enormous amounts of energy without even removing an atom’s worth of mass.
Even a uranium atom converts to less than 4x10[sup]-8[/sup] Joule of energy. I wouldn’t call that “enormous amounts of energy.” Atoms are _tiny_.
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### Author:  [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)
#### Post date: [June 13, 2004, 5:26pm UTC](https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115/13 "2004-06-13T17:26:32Z")
> [@MrFantsyPants](#):
>
> Mass is not energy and energy is not mass.
Yes they are. [The Equivalence of Mass and Energy](http://www.impcas.ac.cn/usr/wjx/zhonglz/jiangzuo/prc/energy_mass_equivalence.html):
> [@](#):
>
> In 1905, Albert Einstein showed that, as a consequence of his special theory of relativity, mass can be considered to be another form of energy. Thus the law of conservation of energy is really the law of conservation of mass-energy. In normal everyday interactions, the amount of mass that is transferred into other forms of energy (or vice versa) is such a tiny fraction of the total mass that it is beyond our sensory perceptions and measurement techniques. Thus, in a chemical reaction, for example, mass and energy truly seem to be separately conserved.
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### Author:  [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)
#### Post date: [June 13, 2004, 5:27pm UTC](https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115/14 "2004-06-13T17:27:48Z")
From the Master
> [@](#):
>
> 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.
from [http://www.straightdope.com/classics/a3\_144.html](http://www.straightdope.com/classics/a3_144.html)
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### Author:  [@MrFantsyPants](https://boards.straightdope.com/u/MrFantsyPants)
#### Post date: [June 13, 2004, 8:41pm UTC](https://boards.straightdope.com/t/when-i-get-a-text-message-on-my-mobile-phone-does-it-become-slightly-heavier/250115/15 "2004-06-13T20:41:53Z")
> [@Qadgop the Mercotan](#):
>
> From the Master
>
> from [http://www.straightdope.com/classics/a3\_144.html](http://www.straightdope.com/classics/a3_144.html)
Well, I stand corrected.