As William Shatner can attest, depositing a partially frozen turkey into a vat of hot oil is a very bad—very explosive—proposition. But why do they do that? Don't blame the bird, blame its water content.
The technical term for what happens is a boiling liquid expanding vapor explosion (BLEVE, pronounced "blevey"). This occurs when an sealed container surrounding pressurized liquid or gas is ruptured, causing an explosive decompression. This is what happens when gas tanks explode (the heat from the external fire causes the gas in the tank to combust and rupture) or when you shoot a fire extinguisher (puncturing the canister again results in decompression).
The problem arises in part because water and oil will not mix with oil being lighter. See, if water is added to the top of a pool of oil, it will immediately sink through to the bottom of the container. This normally isn't a problem unless the oil has been heated above 100 degrees C—beyond the vaporization point of water. As the water sinks—ensconced in its little oily prison—it will vaporize, exponentially expanding in volume and splattering oil all over the place. With the introduction of enough water, the oil can also boil over the fryer and onto the burner below. [Life Goes Strong - The Energy Library - Wikipedia - top image: SunnyS / Shutterstock]
You can keep up with Andrew Tarantola, the author of this post, on Twitter or Google+.