Love it or hate it, the freedom to say obnoxious and subversive things is the quintessence of what makes America America. But our say-almost-anything approach to free speech is actually relatively recent, and you can trace it back to one guy: a Supreme Court justice named Oliver Wendell Holmes....

Scientists took about 300 years to lay out the Periodic Table into neat rows and columns. In one hour, we’re going to mess it all up.  This episode, we enlist journalists, poets, musicians, and even a physicist to help us tell stories of matter that matters. You’ll never look at that chart the...