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Asked by matty23 to Adam, Catherine, Karen, Leila, Nazim on 15 Mar 2012. This question was also asked by nezza.
Question: How many atoms are there in the world
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Adam Stevens answered on 14 Mar 2012:
Squintillions.
12 grams of Carbon contains 6.0221415 × 10^23.
That’s more than 600000000000000000000000000 atoms.
The earth has a mass of 5.9742 × 10^24 kg
That’s more than 500000000000000000000000000000000 grams.
Multiply them together and you get about
100000000000000000000000000000000000000000000000000000000000000 atoms.Hope that helps!
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Leila Battison answered on 15 Mar 2012:
And that’s not even counting all the plants, animal, and bacteria that live on the surface of the world, and the atoms in the atmosphere!
More than you can even begin to imagine!
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Karen Masters answered on 15 Mar 2012:
Oooh a great question for practising estimating things….
Well. The Earth weighs 6×10^24 kg (that’s 6000000000000000000000000 kg) according to Google. It’s mostly made of rock I think… hmm interesting.
Well this article (http://www.universetoday.com/15048/what-is-the-earth-made-of/) says the Earth is 30% iron, 30% oxygen, 15% silicon and 15% magnesium (roughly).
Now for more Google which says the atomic mass of iron is 55 g (ie. 1 mole of iron atoms weigh 55g), oxygen is 16g, silicon is 28g and magnesium 24g.
Do you know what a mole is I wonder – it’s just a definition of a weighable amount of atoms. 1 mole of atoms is 6×10^23 atoms.
2×10^24 kg of iron, or 4×10^25 moles (mass/mass of a mole) or 2×10^49 atoms of iron
2×10^24 kg of oxygen, or 1×10^26 moles, or 6×10^49 atoms of oxygen
1×10^24 kg of silicon, or 2×10^49 atoms
1×10^24 kg of magnesium, or 2×10^49 atoms.Add it together and it’s 1×10^50 atoms by my estimate. That’s
1 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 atoms.
That’s a lot!
Did you know that in some sense a neutron star is just once single massive city sized atom (made of just neutrons).
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Nazim Bharmal answered on 18 Mar 2012:
Look at a beach and see the grains of sand: there are a lot more atoms in your body, than there are grains of sand on that beach.
I can’t even begin to imagine how many atoms there are in the world!
Comments
Karen commented on :
Leila – I think compared to the planet all the plants and animals on the surface would hold a negligible amount of atoms – be interesting to estimate that too….
Adam commented on :
Surely all the living things are made up of carbon etc. originally taken from the Earth (or is that opening a whole new can of worms?!) so they wouldn’t make too much difference?
It’s interesting that both are estimates are only out by (I think) an order of magnitude! I wonder what would happen if you took the fact that most of the atoms aren’t in atomic form into account? I assume the molecular binding energies are very small, but with that number of atoms it could make a difference to the total mass!
Karen commented on :
I couldn’t be bothered to count all the zeros in your answer Adam! I guess there’s a reason for the use of scientific notation. Still it’s fun to write them out long hand sometimes.
Order of magnitude I doubt it’d change much because of molecular binding energy. I could be wrong there though.
Adam commented on :
10^23 atoms/gram x 10^24 grams -> 10^50atoms
BAM. Science.
Adam commented on :
I reckon molecular bonding would be a decimal point at about 10^10atoms so not significant on an order of magnitude, but not small!
(Apparently mass of a proton ~10^7 times chemical binding energy.)