-Did you know that your hair is not actually alive? Only the follicle is alive.
-Cells start in the follicle and mature as they move upwards and out of the scalp. As this happens the nucleus dies and the keratinized cells form the hair strands.
-At least 80% of your hair is made up of keratin. 10-15% is water, and the rest is pigments, minerals, and lipids. 
-On an even smaller scale, there exists both physical and chemical bonds that hold together the polypeptide chains of said keratin. These bonds account for your hair's strength.
-Hydrogen bonds are physical, and are temporarily broken down by water or heat
-Salt bonds are also physical, and are broken down with strong acidic or alkaline solutions
-Disulfide bonds are chemical, and are only broken down by chemical relaxing, perming, and bleaching.
-Most people can grow their hair to a maximum length of 16-32 inches...I say most because I have seen hair that can nearly sweep the floor on individuals who have clearly chosen hair growth as a superpower; let's hope they use it for good and not evil.
-Back in the follicle, there is something called the matrix. This is where hair is born. The matrix contains keratinocytes and melanocytes (both of which are also found in the cortex).
-Melanocytes inject hair with pigments that will last an entire growth cycle. 
-On an atomic level, your hair is largely made up of carbon, oxygen, hydrogen, nitrogen, and sulfur. These are the elements that make up the amino acids that are keratinized protein. 
-Since I don't think I can do better than answering the question on atomic level, this concludes the blog...let me know if you are interested in reading more about the growth cycle and phases. 

Stay classy, Saskatoon.