Setting the record straight: Readers Questions II

This archived article was written by: Nathaniel Woodward

Once again my email inbox is bursting at the seams with emails from my readers, some with follow-up science questions to what I have written and many more with additional questions they have asked me to answer. It has been my interest since my first article to educate my readers on science concepts that get a bad wrap or are misunderstood, so I am more than happy to research and provide answers.
Q1-Devin from Price, Utah, asked, “How small are atoms? I’ve seen the math, but can’t visualize the concept.” That’s a really fun question to visualize once you get ahold of exactly how unbelievably tiny atoms are. I found the answer in a biography I recently read about Albert Einstein who gave the number of atoms you’d find in an average-sized human.
Using his formula, if we made each atom in your body the size of a popcorn kernel, it would bury the entire continental United States…200-miles deep. That’s the distance from your toes at sea level to the International Space Station.
What’s even more amazing is the structure of the atom itself, which, believe it or not, is almost entirely empty space. The atom consists of a nucleus of hadrons (protons and neutrons) and a shell of “orbiting” electrons and to get an idea of how wide of an orbit these electrons have, we’d have to imagine an atom the size of an American football stadium. If a single atom was this size, the electrons would be in the nosebleeds while our nucleus would be at the 50-yard line, only the size of a grape.
This means our nucleus would have to be incredibly dense, on the scale similar to our first analogy. To get an understanding of just how dense a nucleus is, I have to borrow an example from a recent TED talk where we are asked to visualise that our atom’s nucleus is the size of a 1x1x1 box. To get the inside of this box to the density of an atom you would have to fit 6.2 billions cars inside. Wow.
Q2-Karen from Henderson, Nev., asked, “How is it that I can control my breathing but don’t have to, like when I sleep?” Because your brain is awesome Karen and the biology that makes it work is very, very old. Look at the relationships we have with other forms of complex life on Earth. What are the things we have most in common? Hearts and lungs would be great examples not just today, but throughout hundreds of millions of years.
The structure of our brains paints a beautiful biological picture of how we share common ancestry with all other life on the planet, notably what makes humans, well, human or what sets us apart. The forward parts of our brain, above your eyes, contain centers where we developed “higher processing,” things like personality, reasoning, decision making or logic, all attributes that gave us huge advantages on the evolutionary path.
So more basic processes like breathing would naturally be located further down, in our cases, in the brain stem. Our bodies need oxygen to make cells function, simple as that, so in order to maintain a good supply, our brains utilize tiny control centers where the signal to breathe in and stop breathing work together.
Your brain knows when to take a breath by measuring how acidic your blood is becoming. Since you can’t have gas bubbles floating around in your blood, your body binds the spent oxygen atoms to carbon atoms in the form of carbonic acid as it makes the trip back to your lungs to be expelled as carbon dioxide.
Your blood pH is on the basic end of the scale, around 7.4, so when you have excess carbonic acid in your blood the pH begins to drop, causing your blood to become more acidic, something your brain wants to avoid. As your brainstem centers monitor your blood pH it sends the single to breathe in whenever if feels the pH is getting a little low. Remember that the next time you hold your breath and feel that “burn” in your chest.