The Dilemma: Either you're a rabid AC/DC fan in search of lyrical meaning or you've got some pressing need to blow something up. Either way, we've got your answer.
People You Can Impress: demolition experts, mustachioed villains from silent movies, and Wile E. Coyote
The Quick Trick: If it's a white powder found in sticks, it's dynamite. If it's a yellow crystal, it's TNT. Use this little mnemonic to remember dynamite's inventor: "Winning a Nobel Prize would be dynamite!" The alternative, that winning would be TNT, just doesn't make any sense.
The Explanation: A lot of people use these two terms interchangeably, and the common misperception is that TNT is the chemical name and dynamite is the colloquial term. But like any good misperception, that's just plain wrong.
We'll start with dynamite. Patented in 1867 by the Swedish chemist Alfred Nobel (as in Nobel Prize), dynamite was discovered when old Alfie was looking for a way to make nitroglycerin more stable and less prone to, well, exploding in your face. By combining nitroglycerine with diatomaceous earth (the ground-up shells of microscopic diatoms, today used as a filtering agent in swimming pools) and sodium carbonate (found in baking soda and soaps), Nobel took explosives in a whole new direction. And because it was stable and wouldn't explode from jiggling, like nitroglycerin, dynamite was initially marketed as Nobel's Safety Blasting Powder. (Well, it wasn't that safe; an explosion at the family factory killed Alfred's brother Emil.) Nobel used the huge profits from his dynamite patent to endow the Nobel prizes—one of which is for peace. He may have been inspired to create the Nobel Prize after a premature obituary in a French newspaper called him a "merchant of death."
As for TNT, it's also a high explosive, but it ain't dynamite. TNT is a yellowish compound with the chemical name trinitrotoluene(try-night-row-TALL-you-een), which is somewhat easier to remember than its chemical formula, CH 3C6H2(NO2)3. TNT was discovered in Germany in 1863 by Joseph Wilbrand. Although not quite as powerful as dynamite (and harder to detonate), the main benefit of TNT is that it's even more stable than dynamite (Wilbrand, for instance, never lost a single brother to an explosion). Also, TNT can be melted down and poured into shell casings. On the downside, however, TNT is extremely toxic.
While TNT packs plenty of bang by itself, it's often mixed with other things. A TNT and ammonium nitrate cocktail will get you amatol, a military explosive. Remix those two and add some powdered aluminum, and you'll get ammonal, a common industrial explosive.
The confusion between TNT and dynamite isn't helped by popular culture. The two are routinely used interchangeably in movies. And in the song "TNT" by AC/DC, deceased lead singer Bonn Scott declares "I'm TNT, I'm dynamite." So which one is it, Bonn?