We have the right to calculate the variety of atoms in your head if we recognize the density and also a consistent called Avogadro"s number. This is really just an estimate, yet it"s walk to it is in a good one. The equation is fairly simple. The variety of atoms of any type of substance in a volume is:

# of atoms = N * (density) * volume / (Molecular Weight).

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N is a continuous called Avogadro"s number and also its equal to 6.022*1023 atoms/mole. That can additionally be molecules every mole. In the over formula thickness times volume is simply the mass. If you know how hefty something is or what the volume and density space you can quickly do this.

Lets begin with a straightforward problem. A liter the water is 1000 cubic centimeters. Water is easy because each cubic centimeter has actually 1 gram that mass. Water is consisted of of 2 hydrogen atoms and also one oxygen atom. Hydrogen has an atomic load of 1 and oxygen has actually an atomic weight of 16. The water has a molecular weight of 18. The liter the water has actually 1000 grams. The variety of moles is 1000/18=55.556moles. The variety of molecules is because of this 6.022*1023*55.556=3.346*1025 molecules. The variety of atoms is 3 time larger because each molecule has three atoms, so there are 1.0038*1026 atoms in a liter the water.

Now us know sufficient to answer your question. A usual human head weighs around 10 - 12 pounds. We room mostly comprised of water. As soon as you go swimming you most likely noticed that virtually everybody floats with just component of your head the end of water. This observation will command you to conclude that our thickness is an extremely close to the density of water. Equipped with every this we have the right to estimate the number of atoms in your head. A lb is 454 grams therefore a 10 pound person head is 4,540 grams. If ns assume that us are mainly water top top the average because our average thickness is roughly that the water climate I have the right to use the above information on water to acquire the answer.

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Moles every head = (4,540 grams) / (18 grams/mole) = 252.22 molesMolecules per mole = 6.022*1023 * 252.22 mole = 1.519*1026 moleculesAtoms every head = 3 * molecules = 4.56*1026

This is 456 trillion trillion atoms!

I"ll conclude on a historical note. Avogadro was an Italian Physicist who very first described the Avogadro continuous as a hypothesis in 1811. He to be trying to recognize why in chemistry reactions including gases the observation that equal quantities of various gases had the same number of moles. This was discovered true also when the masses were very different. The idea that a mole of any substance has specifically the same number of atoms (or molecules) no issue what the problem is made of was explained by Avogadro and his name has stuck come his number ever before since.