How many grains of sand are there in the Sahara desert?

Question

SERIOUSLY! And no silly answers!

Answer 1

The Sahara is the world's largest hot desert, over 9,000,000 km² (3,500,000 mi²).

The volume of a grain of quartz sand with a diameter of 0.060 mm (a lower bound) is 1.13 x 10^-13 m^3 with a mass of 3.00 x 10-13 g. As an upper bound, the volume and mass of a grain of sand with a diameter of 2.10 mm are 4.85 x 10-9 m3 and 1.28 x 10-8 g.[1].

The deposits of the modern-day Sahara are generally less than 100 meters thick, though there are some sandy landforms that can reach 450 meters high. (3)

Area of the Sahara: 9 000 000 (km^2) = 9.0 × 10^12 m^2.
Depth of the sand in the Sahara: approx 100m
Volume of sand in the sahara: (9.0*10^12)*(100m) = 9.0*10^14 m^3.
Volume of a grain of sand: 1.13 x 10^-13 m^3

Therefore the # of grains of sand in the Sahara is: (9.0*10^14 m^3)/(1.13 x 10^-13 m^3) = approx 8.0x10^27 grains of sand or 8000000000000000000000000000 grains of sand or 8 octillion grains of sand.

Source(s):
http://en.wikipedia.org/wiki/sahara_dese...

http://en.wikipedia.org/wiki/sand...

Answer 2

The highest of sand I counted was like 20, I believe there are more grains of sand in the Sahara Desert.

Answer 3

This is a question that cannot be answered with any accuracy. However, it is interesting to consider how we can get as close as possible to a satisfactory answer. We would need first to find the volume of sand in the world (by far the biggest stretches of sand being the Sahara and Gobi Deserts), then plot the particle-size distribution at each place, and finally work out the average particle size of the sand.

If the question is taken literally – namely, how many grains of sand there are in the world – we are interested specifically in rock detritus with a particle diameter of 0.06-2 mm. According to standard sedimentological classification, detrital material is called clay if the diameter of the particles, d, is less than 0.002 mm, silt if d is 0.002-0.06 mm, sand if 0.06-2 mm, gravel if 2-64 mm, cobble if 64-256 mm, and boulder if greater than this.



The Sahara Desert.

Let’s assume that all the grains of sand are spherical and of equal size. If so, they will ‘pack together’ with maximal compaction, such that the spheres themselves fill 68% of the total volume. If the diameter of the grains is on average 1 mm, this would give 1.30 × 109 (1,300 million) grains in one cubic metre of sand.

For the sake of argument, say that all the sand in the world forms an even layer, 10 cm thick, over the entire surface of the earth, which covers 510 million km2 (200 million square miles). Then the volume of the sand will be 5.10 × 1013 cubic metres and the number of grains thus
5.10 × 1013 × 1.30 × 109 = 6.63 × 1022
If the layer of sand was only half as thick, the number of grains would be halved, and if the layer was a metre thick there would be ten times as many. As it is, we simply do not know how thick the layer is in reality, nor what the average particle size is. It is perhaps fun to compare our result with Avogadro’s number, which is about 10 times greater.

By way of comparison, consider the famous Indian legend about the invention of chess and the grains of rice. The inventor presents the game to the king and asks for payment in grains of rice – one for the first square, two for the second, four for the third, eight for the fourth, and so on. There are 64 squares. The result comes out at 1.84 × 1019 grains of rice, which is about 4,000 times less than the number of grains of sand in the world on the basis of our calculations above. To bring the number of grains of rice up to our number for the grains of sand, you would need a chessboard with 76 squares instead of 64.

Answer 4

Cant be done because the boundary of the SAHARA is undefined but its possible if you had the correct area and don't forget depths have to be located, then by elimination how much 1 cwt sliced down to i once x how many grains in that amount x by area and weight to produce volume the answer would go into sexdecillion or better still infinity

Answer 5

Regions of sand dunes (erg) occupy only about 15% of the Sahara; “stone deserts,” consisting of plateaus of denuded rock (hammada) or areas of coarse gravel (reg), cover about 70% of the region; mountains, oases, and transition zones account for the remainder. Sparse vegetation is found in most parts of the Sahara, with the exception of the sand dune regions.

So, not as many as you would think!

Answer 6

I haven't checked it all myself, but I think you'll find that most of the Sahara desert is rock not sand

Answer 7

That's really not a stupid question. I'm sure there is a logical way to get an estimate using mathematics and physical concepts combined with meteorological and geological field work. However, since there is no practical reason for obtaining such information, no lab would be able to get funding for such a project. Sorry!

Answer 8

Re: Old man of Coniston - there are around 200000000000 stars in our milky way, far less than the number of grains in the esties above.

Answer 9

I bet there's more stars in the Milky Way!.
I will put £1,000,000 on winning at odds of 1/9 on!.

Answer 10

Terracotta