I am not a physicist, but from doing an internet search, there are approximately 7 x 1027 atoms in the average human body, based on a 70kg adult human male. Generally, a smaller person would contain fewer atoms; a larger person would contain more atoms. So in a foot, there would be fewer atoms, but still an awful lot!
Doing some quick research, the foot makes up about 1.5% of your body weight. And an average adult male weights 70kg, as Hannah said. So the foot is probably about 700-800 grams.
Now, lets assume you are mostly water (oxygen and hydrogen) and carbon. Looking at the periodic table, that gives the atoms in you an average molecular weight of about 10 atomic units. Using this and a constant called the Avagadro constant 6.022e+23 (which is the number of atoms in 1gram), we find an answer of about 10^24 (10 and 23 zeros after it!)
Comments
Oliver commented on :
I’m a physicist – sorry to steal this question!
I answered something really similar here : /nobeliumm19-zone/question/how-many-atoms-are-in-a-a4-piece-of-paper/
Doing some quick research, the foot makes up about 1.5% of your body weight. And an average adult male weights 70kg, as Hannah said. So the foot is probably about 700-800 grams.
Now, lets assume you are mostly water (oxygen and hydrogen) and carbon. Looking at the periodic table, that gives the atoms in you an average molecular weight of about 10 atomic units. Using this and a constant called the Avagadro constant 6.022e+23 (which is the number of atoms in 1gram), we find an answer of about 10^24 (10 and 23 zeros after it!)