If you need to chill a bunch of warm beer for your Fourth of July party, here's the fastest way to do it. You can also turn this into a summer science lesson for your kid if you want.

The best way to chill a beer super-fast involves salt water. If you're a "Mythbusters" fan, you might know about this. They tested it back in 2005, but Popular Science just did a big article about it too.

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Even without salt, ice water cools down a beer faster than just ice because the water completely surrounds the can. Salt water works even better because it freezes at a lower temperature, especially if you use a ton of salt.

Normal water freezes at 32 degrees, salty water won't freeze until it's about five below zero. Basically, it's because the sodium molecules get in there and prevent the water molecules from forming into crystals.

Now, ice actually melts faster in salt water, don't let that fool you. It's not because the salt is raising the temperature of the ice, it's just converting the ice into salt water that's still the same temperature. Which is right around 32 degrees.

If you add even more ice to the mix, the temperature of the water will keep dropping but won't freeze. You can get it down to something like 25 degrees instead of 35. That extra ten degrees is huge.

In normal ice water, it takes about 15 minutes to get your beer down to a perfect 38 degrees. In really salty ice water, it should only take about five.