Welcome to brain Stuff from house stuff works dot com where smart happens. Hi. I'm Marshall Brain with today's question, how does nitroglycerin work? In eighteen forty six, scientists discovered nitroglycerin. It's pretty simple to make. You start with nitric and sulfuric acids in an ice bath and you slowly add glycerin to it. You have to make sure to add the glycerin at a slow enough rate to avoid a temperature rise, because if the temperature rises, you can get
an explosion. The nitroglycerin that gets formed creates a layer on top of the acid. If you extract this layer stay with an eye dropper, you have the desired product. It's pretty remarkable stuff, but not very stable. If you take a drop of it and put it on a piece of paper and put that piece of paper on a countertop and tap it with a hammer, it will explode with a loud pop. Just a few grams of nitroglycerin can create an impressive explosion. Why is it explosive?
Compare a molecule of gasoline to a molecule of nitroglycerin and you can see why. Gasoline contains eight carbon atoms. And eighteen hydrogen atoms. If you light it, it combines with oxygen in the air to burn. A gallon of gas might produce a fireball when you burn it, but it's not really an explosion because it has to suck in oxygen from the air to burn, and that takes time. A nitroglycer molecule has three carbon atoms, five hydrogen atoms,
three nitrogens, and an impressive nine oxygen atoms. In other words, each nitroglycer and molecule contains almost all the oxygen needed for complete combustion, so it can burn much faster explosively. However, the instability of nitroglycerin is a problem. If you drop nitroglycerin or bang it or round, it can explode spontaneously. Alfred Nobel is the first guy to figure out a way to stabilize it. He mixed it with something like
sawdust to create dynamite, which is much more stable. For more on this and thousands of other topics, visit how stuff Works dot com. To learn more about the podcast, click on the podcast icon in the upper right corner of our homepage. The house Stuff Works iPhone app has a ride. Download it today on iTunes.