How many atoms are there in the world?

The quick answer is: more than you can count! But we can get an estimate of the number of atoms in the earth by first knowing what its mass is. The mass of an object is a measure of how much material the object has. The mass of the earth is 5.98*1027 grams. That's the scientific way to write a large number that has a lot of zeros. We can write the mass of the earth with all the zeros like this:

5,980,000,000,000,000,000,000,000,000 grams

Below is a table that shows the breakdown of the fractional amount of the earth for the most abundant types of atoms (also called the element). Some of these values are estimates since we really don't know exactly what the center of the earth is made of but scientists have pretty good theories about it. In the table is also a list of how many grams a mole of an element weighs. The bottom line is that there are about 1.33*1050 atoms in the world. If you want to write it with all the zeros it would be:

133,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000

 Element Gramsper mole Fractionof the Earth Amount in theEarth in grams Numberof atoms Iron 55.8 0.35 2.09*1027 2.26*1049 Oxygen 16.0 0.30 1.79*1027 6.75*1049 Silicon 28.1 0.15 8.97*1026 1.92*1049 Magnesium 24.3 0.13 7.77*1026 1.93*1049 Sulfur 32.1 0.02 1.20*1026 2.24*1048 Calcium 40.1 0.01 5.98*1025 8.98*1047 Aluminum 27.0 0.01 5.98*1025 1.33*1048 SUM 1.33*1050

Author:

Drew Weisenberger, Detector Scientist