I don't know how the weather has been where you live, but here in the Midwest it finally just turned summer time. It's been absolutely frigid almost all year and now it's hot and humid. Right now nothing sounds better than a glass of iced tea or lemonade when I'm out wandering around or catching the latest World Cup match. Have you ever wondered why your ice cubes crack and break in a cold glass of your favorite frosty beverage? One YouTube video attempts to explain the phenomenon.
In YouTube video by Periodic Videos , the team used slow motion technology to help explain why your once perfectly cube-ish ice splits and breaks in your cup. The video starts off with an awesome, very slow video of some ice being dropped in a glass and the ensuing crackling that follows. Turns out, as the narrator Martyn Poliakoff , Professor at University of Nottingham explains, the reason this happens is something called differential expansion.
No matter how cold your beverage is, it's likely that your ice cubes are much colder. In an infographic that makes a lot of sense, they explain that the inner part of the ice cube is even colder than the frosty outside. As the warmer liquid surrounds the ice cube, the outer layers start expanding much faster than the inner bit. The pulling away of the warmer edges faster than the inside can handle causes the cracking an splitting of the cube.
The folks at Periodic Videos then tried using a warmed up ice cube that sat at room temperature to see if the differential expansion occurred or not. Turns out that ice that warms up to its melting point before being dropped into a cup of liquid, it doesn't crack or break. I would think that it wouldn't be quite as good at cooling down my lemonade though. In a final experiment, which was one of the coolest things I've ever seen, an ice cube was dropped into liquid nitrogen. The ice didn't expand, but contracted on itself because the outside was so much colder than its temperature.
So, next time you're pool side or couch side and enjoying a cool drink, it might be worth it to play with your ice cubes a little bit to test out the experiments for yourself. I am definitely going to give this a try and see if I can come up with some more ways to re do this experiment. I may not have a degree in any scientific fields, but I sure do like to pretend.
If you're into more slow motion, scientific videos, check out the Periodic Videos clip above where they pour mercury into liquid nitrogen. While I don't recommend this experiment for anyone at home, its definitely cool to see some professionals playing around with the elements. This particular reaction is called the fuel coolant reaction, but it just looks totally awesome.