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What is the most basic composition of our body?  

Let’s say that we had access to fancy laboratory equipment capable of determining the most fundamental composition of an object. If we used this equipment to assess a man or woman it would spit out some interesting data on our most basic level of composition - elements. Elements are substances that cannot be broken down into other substances. Scientists have determined that there are 100 or so of these elements in nature. Some of the more recognizable elements include carbon, oxygen, hydrogen, nitrogen, iron, zinc, copper, potassium and calcium.

All of the elements known to exist can be found on the Periodic Table of Elements, which we have all come across at one point or another in our schooling.Now, imagine that everything that you can think of is merely a skillful combination of these same elements. This includes cars, boats, buildings, clouds, oceans, trees, and of course our body. In fact, our body employs about twenty-seven of the elements as displayed in the table below (Elements of the Body Table for printable version).  

What is the element composition of our body? 

The late, great Carl Sagan in his personal exploration of the cosmos said that we are made up of “star stuff”. What he meant was that our body is made up of many of the very same elements that make up planets and other celestial bodies in the universe. We humans as well as other life-forms on our planet have simply borrowed these elements. Interestingly, four of these elements, namely oxygen, carbon, hydrogen, and nitrogen, make up greater than 90 percent of our body weight. Since the majority of these elements are found in our body as part of substances such as water, proteins, carbohydrates, fats, and nucleic acids (DNA and RNA), it only makes sense that these substances must be the major chemicals of our body. For example, a lean, young adult male’s body weight may be approximately 62 percent water, 16 percent protein, 16 percent fat, and <1 percent carbohydrate. Most of his remaining weight (about 5 percent) would be attributed to minerals.

What is the relationship between elements and atoms? 

Atoms are the building blocks of everything that exists. From the clothes on your back to the car you drive to the food you eat-everything is comprised of atoms. Each individual atom belongs to only one element. This is to say that even though there are an incomprehensible number of atoms on this planet and the universe making up everything we know and are yet to know, all of these atoms belong to only one of 100 or so elements. This is similar to each one of the billions of people living on this planet being native to only one of a hundred or so countries. 

So, in a world where size is judged relative to the size of humans, the atom is indeed miniscule. It has been said that if we could line up a million atoms end to end they would barely cover the distance across the period at the end of this sentence. However, they do indeed exist even though you cannot see them with the naked eye.  

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