Questions of science.
July 5, 2010 6:54 PM   Subscribe

"You are part of everything you love" is a song lyric that's really captured my imagination. I've got questions on how accurate this sentiment is scientifically.

1. I know that the vast majority of the human body is made out of oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. What are their functions in the body, though? For instance, I know that calcium's part of of teeth and bones...

2. What elements are found in everyday things? What's in an apple? A book? My brick house? In general, what elements are found in all fruits? All buildings? What's plastic made out of?

3. Okay, so this is where that lyric comes in. Is it very likely that stuff from #2 has ended up inside of me? I mean, is it possible that atoms from a book published in the 18th century are hanging out inside my spine right now? Does decomposing allow for that to happen, or do properties of chemical bonding and stuff like that make it unlikely?

4. Atoms make up elements, which make up cells, right? I know that the number of protons in an atom determines what element it is - for instance, 6 protons makes it carbon - but what determines the number of protons in the first place?


(I feel ridiculous for having to ask these things. I mean, I've made an A in every science class I've ever taken, but it seems like I lack even basic knowledge in understanding everyday life.)
posted by estlin to Science & Nature (14 answers total) 10 users marked this as a favorite
 
(I know I'm asking a lot - feel free to answer any or all of the parts of the question. Thanks!)
posted by estlin at 6:55 PM on July 5, 2010


I present you this book:


A Short History of Nearly Everything

It shall answer the questions, between the things you know.
posted by alex_skazat at 7:13 PM on July 5, 2010


alex_skazat , I actually just checked that out of the library yesterday! I'm glad to hear that it'll help clear things up.
posted by estlin at 7:21 PM on July 5, 2010


2. What elements are found in everyday things? What's in an apple? A book? My brick house? In general, what elements are found in all fruits? All buildings? What's plastic made out of?

3. Okay, so this is where that lyric comes in. Is it very likely that stuff from #2 has ended up inside of me?


Do you ever eat apples? 'Cause, yeah, that's how that works.
posted by Sys Rq at 7:23 PM on July 5, 2010


1. [What are the elements' functions in the human body]

This list seems to be pretty good. I haven't vetted it (nor am I qualified to do so), and the writer seems to be a mineral education non-profit, so I guess it's legit? Alternatively, wiki.

The list should also cover a lot of #2, it lists some sources for certain elements, and the knowledge about the function might imply its existence in (organic) material.

#3: Certainly it's possible. I remember when applying for university, there was a Fermi Problem about that topic - #12 in that set. Also see #6 on the set.
posted by Lemurrhea at 7:54 PM on July 5, 2010


estlin: "Is it very likely that stuff from #2 has ended up inside of me? I mean, is it possible that atoms from a book published in the 18th century are hanging out inside my spine right now?"

I think you might like this anecdote:

I decided to challenge the class to consider a related but simpler question: "If I took one liter (about one deep breath) of an inert gas and released it into the outside air, then waited until it completely mixed with the entire atmosphere of the Earth, what would be the average number of molecules of that substance that I would breathe in each breath?"

All of the students felt intuitively that the volume of the atmosphere must certainly be so large that a single liter of air would be "negligible" in comparison. so that we are not likely to be breathing air once breathed by Julius Caesar—much less the air in his last breath.

[...]

As the students worked their computations using the spreadsheets, a few got bogged down in the early stages and some were unable to complete the final solution. Several of them, however, not only finished, but arrived at answers that substantially agreed. Four students determined that, on the average, there would be about 8 molecules of the original gas per liter of atmosphere, so the probability of breathing at least one molecule of the gas per breath is excellent. (They estimated the volume of the atmosphere to be 2.5x1021 liters, and found that the ratio of 2x1022 molecules to 2.5x1021 liters is 8 molecules/liter.) Thus, we could literally be breathing some of the molecules in Caesar’s last breath! During a discussion of the results on the next day of class, we were all amazed at the result, which seemed counter-intuitive to everyone, including myself.


posted by Rhaomi at 8:03 PM on July 5, 2010 [4 favorites]


Long time lurker -- I had to make an account specifically to respond to this question!

In response to 4:

The number of protons does, indeed, determine the type of element of any atom. As you're aware, electrons can be shared or donated between atoms, but protons don't change. The only way that you *can* change the number of protons is through nuclear fusion or nuclear fission. This always means that you're changing that atom to a new element/type of atom -- or perhaps more accurately, that you are destroying that first atom and creating a new one in its place.

Hydrogen was formed when the universe first cooled down enough to allow it. Hydrogen eventually pulled itself together into stars, due to gravity, and because the stars were hot enough and dense enough, nuclear fusion began to occur. Two hydrogen atoms became a helium atom, a helium atom and a hydrogen atom became a lithium atom, and so on and so forth. The process is called nucleosynthesis, and all the atoms in the universe of elements lighter than say Iron were originally formed in the heart of a star. Anything heavier had to form during a supernova.

I love that a song lyric prompted you to ponder these things! What's the lyric from? This sense of material entanglement with the universe also fascinates me. Here's another song lyric that really "does it" for me:
We are stardust
We are golden
We are billion-year-old carbon
And we got to get ourselves
Back to the garden

- CSN, "Stardust"
posted by Made of Star Stuff at 10:12 PM on July 5, 2010 [5 favorites]


Great question. Just had to pop in to say:
Made of Star Stuff, the song title is "Woodstock," and it was written by Joni Mitchell.
posted by Paris Elk at 11:02 PM on July 5, 2010


It seems to me that your main question is this:

Is it very likely that stuff from #2 has ended up inside of me?

I think that will come down to each thing. An apple will, unsurprisingly, become part of you when you eat it (I'd be quite fascinated to read an intelligent breakdown of how long and where each component of the apple remains in your system). Your bricks? You've certainly breathed in some clay from them. Dust from the Parthenon? It's quite possible that a molecule or two has found its way to you. The book? If it's locked up in a vault, possibly not. If you're read it, then almost certainly.

All this being said, it suggest that the things you love are parts of you. For you to be a part of everything you love, as the lyric suggests, then your best bet would be to rub up against them when you see them next. This may or may not be a good idea.
posted by twirlypen at 3:13 AM on July 6, 2010 [1 favorite]


Rhaomi's example (dispersing a litre of gas) reminded me that when I was a kid, my father did similar calculations to demonstrate similar findings regarding peeing in the ocean.
posted by carmicha at 5:47 AM on July 6, 2010


CSN, "Stardust"

Actually, the song is called "Woodstock," it was written by Joni Mitchell, and her original version is infinitely superior.

posted by Sys Rq at 5:58 AM on July 6, 2010


1. I know that the vast majority of the human body is made out of oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. What are their functions in the body, though? For instance, I know that calcium's part of of teeth and bones...

Proteins are polymers composed of amino acids linked together through amide bonds. Amino acids are made primarily of nitrogen, carbon, hydrogen, oxygen with small amounts of sulfur, phosphorous, or copper depending on the amino acid. Proteins are very important in the body - they are structural as well as fulfilling numerous other roles from "molecular messenger" to "garbage truck". Proteins are distinguished from one another by the content and order of their amino acids as well as their overall shape and flexibility. They often help catalyze other chemical reactions critical to the body's function by acting as enzymes.

Carbohydrates, the basic fuel for animal bodies, is comprised mainly of carbon, hydrogen and oxygen. They are broken down and oxidized by the body and converted in to heat and forms of chemical energy that cells use to keep all their many processes running smoothly. They can appear as single molecules (like glucose, which has the well-known formula C6H12O6) or as long chains of single molecules linked up together, which are known as starches. There are many different combinations of sugar molecules that can form starches. In addition to being fuel, carbohydrates also function in other more complicated ways in the body - in biology, everything is multi-purpose!

Lipids, which are hydrophobic (greasy) substances, are also very important. They are composed of carbon and hydrogen with varying degrees of oxygen. They are capable of storing energy very effectively (as fat) due to the nature of their chemical bonds. Like everything else, lipids also have lots of complex "evening jobs" in addition to their energy storage role.

Nucleic acids, the molecules that form DNA and RNA polymers, are of course supremely important as they carry the genetic blueprint for everything that happens within a cell, tissue and organism. The nucleic acids, as well as the sugar backbone that they bind to in DNA and RNA, contain carbon, nitrogen, hydrogen, and phosphorus.

Other elements in addition to the ones listed above are also very important in the body. For example, iron allows hemoglobin within red blood cells to bind oxygen and carry it throughout the body, releasing it wherever oxygen saturation is low, which is the reason why our circulatory system keeps all our tissues alive. Magnesium or copper are sometimes required for protein enzymes to do their jobs. And of course, in addition to the nucleic acids, lipds, carbohydrates and proteins, the body is chock full of other, smaller molecules that serve hundreds of purposes - many of which contain rarer elements.

2. What elements are found in everyday things? What's in an apple? A book? My brick house? In general, what elements are found in all fruits? All buildings? What's plastic made out of?

Maybe this will help give an idea: wood (trees) are made mainly of celluluse, which is a carbohydrate starch. An apple isn't all that different, but it has less cellulose and therefore a less "woody" structure; both are made of cells fairly similar to our own. A brick is a ceramic material, which can be made of many things, but when it is made of clay, it is comprised mainly of aluminum, silicon and oxygen with traces of other metals. Plastic is a huge category and it can be made of many things, from chains of carbon and hydrogen similar to carbohydrates to very complicated ring structures containing other elements like nitrogen. However, all plastics are polymers, meaning they contain long chains of repeating units.

3. Okay, so this is where that lyric comes in. Is it very likely that stuff from #2 has ended up inside of me? I mean, is it possible that atoms from a book published in the 18th century are hanging out inside my spine right now? Does decomposing allow for that to happen, or do properties of chemical bonding and stuff like that make it unlikely?

It's absolutely possible that pretty much anything that hasn't been hermetically sealed is inside of you. The idea that our bodies are fixed and stable is really an illusion - for example, nearly 100% of the cells in your gut (intestinal tract) will be die and be replaced with newly built cells (built from the food you eat) in about 10 days. Although some neurons in your brain can live an extremely long time (as long as your lifetime), almost everything else in the body is completely discarded and replaced pretty frequently. Except for a few cells up in your scull, you're quite literally not the same person you were last year. Isn't that amazing??? And yes - it's the incredibly complex interaction between the different species on earth - those that build and break things down, those that consume and excrete, from bacteria to people - that allows this all to happen.

4. Atoms make up elements, which make up cells, right? I know that the number of protons in an atom determines what element it is - for instance, 6 protons makes it carbon - but what determines the number of protons in the first place?

This is an interesting question that can't quite be answered. There's no "blueprint" anywhere that tells an atom to have 6 carbons - 6 carbons just happened to come together to form an atom which happens to have the unique chemical properties that make it carbon in the course of the interaction of basic elements of matter that exist in the universe. HOW exactly that works is a question for a physicist, not me :)

(Apologies for any typos I may find later - I really ought to get back to work!!)
posted by Cygnet at 8:44 AM on July 6, 2010 [2 favorites]


Um, talk about typos -- that should read "6 protons just happened to come together to form..."
posted by Cygnet at 12:42 PM on July 6, 2010


Thanks much, guys! After a lengthy estrangement from science - aided by joyless textbooks - I feel like this question is a start at reconciliation, of realizing just how fantastic our universe is.

A Short History of Nearly Everything did not disappoint in helping to answer my question (nor did it disappoint in anything else, for that matter - what an fascinating, accessible book! ) From pg 134:

[Atoms] are also fantastically durable. Because they are so long lived, atoms really get around. Every atom you possess has almost certainly passed through several stars and been part of millions of organisms on its way to becoming you. We are each so atomically numerous and so vigorously recycled at death that a significant number of our atoms - up to a billion for each of us, it has been suggested - probably once belonged to Shakespeare. A billion more each came from Buddha and Genghis Khan and Beethoven and any other historical figure you care to name.

He goes on to talk about how atoms are thought to exist for 10^35 years. Wow.

Also, Rhaomi, your link reminded me of another interesting page I've read: Shakespeare's Atoms (previously on the Blue)
posted by estlin at 9:57 PM on July 8, 2010 [1 favorite]


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