So Hubby and I are huge fans of the show “The Big Bang Theory”. Even though it pokes fun of scientists (well, physicists really…although the one microbiologist on the show did have some interesting quirks!), I can’t help but find it exceedingly clever…and hilarious. Not to mention the plots are limited to single episodes, so we’re not completely Lost if we miss one episode. Well Hubby recently found this NY Times Science article about the show, which then referenced a blog that has gone unnoticed by both of us – The Big Blog Theory.
Now I wouldn’t be reviewing this blog if it was just about a TV show, no matter how much I love said TV show. This is actually a pretty interesting science blog (although I’m willing to bet it’s a bit more entertaining if you watch TBBT). It’s written by Dr. David Saltzberg, a particle physicist at UCLA and the scientific consultant for the writers of the show. In this past week’s blog, he reviews the “square-cube law”, which dictates proportion with regards to an object’s size and mass. This, of course, is discussed in relation to a conversation that took place on a recent episode, wherein two of the show’s characters were discussing the possible benefits of giant ants. But the ever-so-wise Sheldon Cooper points out that physics prevents giant ants from existence, explained by Dr. Saltzberg:
The evolutionary biologist, J.B.S. Haldane, won this argument already in his 1926 essay “On Being the Right Size“. In his essay, Handane did more than observe elephants are larger than mice but explained, using physics, how changes in size demand changes in form.
A typical ant we know and love is about 5mm long and has a mass of about 5 milligrams. The giant ants you might like to have around would be 1000 times longer. Not just longer, but 1000 times wider. Not just wider, but 1000 times taller. To calculate the new mass of the giant ant we have to multiply these all togher–a billion times the volume. At the same density, a giant ant would weigh about 5 tons. But its legs would only be wider in two dimensions. They are a million times stronger, but that is not enough–for a creature a billion times heavier. Before taking their first step they would break all their legs, leaving them immoblile and harmless. While mass increases as the cube of size, the function of its structure improves only as the square, hence the name “square-cube law”.
I daresay I understood this explanation of the square-cube law, which is a considerable feat in light of my ineptitude at physics. While this was already fascinating enough for me, Dr. Saltzberg expands the application of this law to the relative sizes of mammals, and how this may dictate the environment they live in:
If our bodies shrunk to the size of an ant, we would be just as hopeless as the giant ant. As warm-blooded creatures, we humans lose body heat with our surface area, which goes as the square of our linear size. Meanwhile our total body mass decreases much faster, as the cube. Even at such a miniscule size, you would never be able to eat enough to stay warm. Whales, warm-blooded mammals of the sea, benefit from growing so large in keeping warm, especially since water conducts heat away faster than air. But they have no legs to stand on, being able to rely on their buoyancy in water. So physicists could have predicted the largest mammals would live in the sea.
Quite an interesting relation of physics to biology! In former posts, Dr. Saltzberg relates Euclid’s postulates to living on a curved planet, shows how Maxwell’s Equations can help create invisibility (in reference to The Lord of the Rings), and discusses why finding a magnetic monopole could prove string theory. And he does it all in a somewhat easy-to-understand and humorous fashion. (I’d be willing to bet that Dr. Saltzberg is quite the sought-after physics lecturer in the UCLA physics department.) Be fore-warned, Dr. Saltzberg only posts once every couple of weeks…I’m sure teaching, research, and consulting for a big-time sitcom take up quite a bit of time on their own. But if you’re a math geek wanna-be, like to watch TBBT, or just enjoy a good science blog, be sure to check this one out.