MadSci Network: Physics |
Hello, That's a tough one, but I'm up for the challenge. I'm assuming that you are looking for the number of particles, in the sense of "atoms", which make up our world. This calls for us to first throw out some facts about the planet so that we can go about calculating a number which is reasonable. The earth is made up of five parts, or layers so to speak. 1) The Atmosphere, which is gaseous. 2) The Hydrosphere, which represents that part of the earth which is liquid water, such as the lakes, seas, and oceans. 3) The Lithosphere, which is the uppermost crust of the earth, which is the layer that you are standing on. 4) The Mantle, which is the layer of rock and metal beneath the Lithosphere. 5) The Core, which is the very hot center of the planet made of iron and crystals. I performed several calculations for each layer based on the materials in them, their thickness, volume, and density, which I will explain as we go. So, let's take it in parts and see what we get for our final number of "particles". The atmosphere is the gaseous envelope which surrounds the solid and liquid body of the planet. The atmosphere is about 700 miles thick and most of all the air is concentrated in the bottom 3.5 mile thickness. The gases within it are mostly Nitrogen and Oxygen, which we breathe. I calculated the volume of the air and then approximately how many atoms that turns out to be. The number of atoms comes out to : 1.112 x10^46 atoms The Lithosphere is made mostly of the cold, rocky crust of the earth which goes down below your feet to a depth of 60 miles. This layer is made up of mostly 11 elements : oxygen, silicon, aluminum, iron, calcium, sodium, potassium, magnesium, titanium, hydrogen, and phosphorous. These 11 elements are all mixed up within different compounds in a crystal form, so that we can call them minerals. Taking all of this and some other factors into consideration, we get : 3.406 x10^42 atoms The Hydrosphere is the layer of water which covers about 71% of the earth's surface. This layer is the combination of rivers, seas, lakes, underground water, and all the world's oceans. The average depth of the oceans is 12,447 feet and their combined mass is 1.35 quintillion tons. From this and other data we calculate : 4.517 x10^46 atoms The Mantle is just below the Crust and is much more dense. The Mantle is 1800 miles thick and is mostly solid, made up of iron and other minerals. For this layer we calculate a value of : 4.434 x10^43 atoms The Core is the center part of the earth and is actually divided into an outer core and inner core. The outer core is 1380 miles thick and is 3 times more dense than the mantle above it. This layer is made mostly of iron and a little bit of nickel. From this we can calculate the number of atoms to be : 1.672 x10^43 atoms The inner core is even more dense and is lies at the very center. This last layer is 800 miles thick and is solid iron. The temperature is very high there and may be as hot as 12,000 degrees Fahrenheit. Phew!!! The number of atoms that I get for this last section is : 9.003 x10^46 atoms So, now that we figured out all the pieces we can add them all up to get the total number of atoms or "particles", which make up the earth from the center all the way out to the edge of the atmosphere. The total number of atoms which make up the earth is : 1.1185 x10^46 atoms That is another way of saying 11,185 billion, billion, billion, billion, million atoms! That's quite alot don't you think?! The entire earth weighs 6 thousand, billion, billion tons!!! As a comparison, you could also look at the earth in terms of the number of nucleons instead of atoms. Nucleons are the "particles" which make up the nuclei of atoms and most often are called either protons or neutrons. They weigh pretty much the same as each other and are what make up the nucleus, which is where most of the mass of the atom sits. Since, for every atom, there are at least 2 or more nucleons, our number should be much bigger. If you could look at atoms with your eye you would see that they all have different numbers of nucleons (just look at a periodic table to see...). A hydrogen atom has 2 of them, an iron atom has 56 of them, and something heavy like uranium, has about 238 of them. The earth's center is where alot of the mass is, and it has all kinds of heavy elements like these. So, if we take all of these differences under consideration, we can calculate the number of "particles" in terms of nucleons. The number that we calculate is : 3.5847 x10^51 nucleons That is another way of saying 3.6 million, billion, billion, billion, billion, billion nucleons! The smaller we go in size of our particles, the bigger the number gets. I hope this helped you out...
Try the links in the MadSci Library for more information on Physics.