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Author Topic: Does photosynthesis create mass?  (Read 3297 times)

Mel Holloway

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Does photosynthesis create mass?
« on: 13/12/2008 19:42:28 »
Mel Holloway asked the Naked Scientists:

On a recent podcast, a listener proposed that photosynthesis was a source of increased mass of the Earth based on e=mc2.

Until now I thought that photosynthesis reduced carbon dioxide to carbon and oxygen and the carbon bonded with hydrogen to form carbon/hydrogen compounds with no net increase in mass.

What do you think?


 

Offline lightarrow

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Does photosynthesis create mass?
« Reply #1 on: 14/12/2008 14:48:54 »
Mel Holloway asked the Naked Scientists:

On a recent podcast, a listener proposed that photosynthesis was a source of increased mass of the Earth based on e=mc2.

Until now I thought that photosynthesis reduced carbon dioxide to carbon and oxygen and the carbon bonded with hydrogen to form carbon/hydrogen compounds with no net increase in mass.

What do you think?
It does create mass in the sense that light's energy from the sun is absorbed from Earth, so Eart's mass increases. When you burn, e.g. sugar (a photosynthesis product) into CO2 and H2O, energy is released so the total mass of CO2 and H2O is slightly less than the sugar's mass; the opposite when CO2 and H2O are converted into the sugar using sun's light.
The mass difference is so small that you can neglect it, in chemistry.
In a nuclear reaction, instead, the mass difference is much greater, about 1/1000 of the mass (for this reason nuclear reactions are so much powerful than chemical reactions).
« Last Edit: 14/12/2008 14:52:36 by lightarrow »
 

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Does photosynthesis create mass?
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