The CBS sitcom The Big Bang Theory is a nerdtastic comedy about a group of highly intelligent but often clueless physics guys and their wannabe actress gal pal. The later development of a pair of female characters as biologist girlfriends has mitigated some early complaints of too much sausage (though, to be fair, not very much testosterone), but it also added a much needed range of geekery to the ensemble.

One of the greatest unspoken aspects of The Big Bang Theory has been the assorted attire of the group. From Raj’s Cosby sweaters to Howard’s retro belt clips, every element of these characters’ clothing is meticulously chosen and meaningful to their personalities. My favorite clothing choice has been the various tee shirts worn by Sheldon and Leonard. Like the physicist characters that adorn them, many of these tee shirts have a scientific element (albeit mostly carbon).  Here are a few of my faves:

Worn by Sheldon in Season 2 Episode 23: The Monopolar Expedition, this ‘De Oxy Ribo’ tee exhibits panels of colorful DNA (deoxyribonucleic acid) graphics. The shirt also lists some factoids including “60,000-100,000 genes”, “3.2B base pairs”, and “ATGC nucleotide sequences”.  The most recent studies estimate that the human genome only consists of  20,000-25,000 genes, not 60,000+, because it is now clear that most of our genome does not actually code for proteins.  At first, this extra genome was called “junk DNA” because it was hypothesized that it was useless.  However, it now appears that much of our DNA is there to help control the genes that are expressed.

Donned by Leonard in Season 5 Episode 1: The Skank Reflex Analysis and Episode 8: The Isolation Permutation, this tee displays the phases of the moon (aka lunar cycle).  The shape of the moon is determined by the area that is lit up by the sun and visible to us on earth.  The animation below shows these shapes as the moon cycles through the

phases as seen by the northern hemisphere.  When the sun and the moon are on the same side of the Earth, the moon is called “new” and the side of the moon visible to us is not illuminated by the sun.  As the moon “waxes”, that is increases its illumination by the sun, the moon progresses from new moon, to cresent moon, to first quarter, gibbous, and finally full moon.

Leonard also wears a variety of graphic tees with various chemical structures on them.  These range from capsaicin (the active chemical in chili peppers that make them hot) to caffeine and adrenaline.  One of the funniest though is his ferrous wheel tee worn on Season 3 Episode 12: The Psychic Vortex.  Ferrous (Fe2+) is a variant of the iron-containing chemical ferric.  It is most commonly associated with rust, which is a chemical reaction between ferric iron and water.  The joke of the tee shirt, is the Fe2+ molecules attached together in a  circle; thus, a ‘ferrous wheel’.

On Season 3 Episode 10: The Gorilla Experiment and Season 4 Episode 4: The Hot Troll Deviation, Sheldon wears this atmospheric CO2 tee shirt.  CO2 is carbon dioxide, which is a potent greenhouse gas.  Since the industrial revolution in the 1800’s, the levels of CO2 in Earth’s atmosphere has been steadily increasing.  This increase is more commonly known as climate change or global warming and is likely involved in the shifting climate and melting ice at Earth’s poles.  Sheldon’s tee shirt shows cartoon CO2 molecules as well as some data graphs depicting changes in atmospheric CO2.

In addition to the many superhero tees, these science-related shirts worn by Sheldon and Leonard play an important role in the personalities of these characters.  They are undoubtedly as intelligent and witty as the men that wear them.  If you are interested, many can be purchased from online vendors including www.thinkerclothing.com and www.tvstoreonline.com.

I’d like to thank the (c) Sheldon Shirts website for listings and graphics.