Distracted Walking

Bob, distracted by a big exam he was about to take, walked out of his residence hall on a mission to make it to class on time. He wanted to get an A on this test. He was listening to his iPod to pump himself up. A friend texted him "good luck." While texting back he failed to notice the ice patch on the sidewalk ahead of him. He hit the ice and his feet flew out in front of him. Not only did he fall, he slid into a group of people and knocked them over.

Why is ice slippery? There's a lot of science behind walking on a warm sunny day, but add some winter into the mix and we have some difficulties. Ice is the solid state of water. Many solids retain their shape, but with ice it's not quite like that. The top layer isn't "packed in" like the rest of the layers, so it can move a bit. This is called a quasi-liquid layer and this thin layer of water causes us to slip. Slips and falls on low-friction surfaces cause many injuries a year and tribologists continue to study sliding surfaces and the role of friction.

What could Bob have done to prevent a fall?

1. Paid closer attention to his surroundings.
2. Taken smaller steps to maintain his balance when he encountered the ice patch.
3. Chosen appropriate footwear for the weather conditions.

Sources:
www.purdue.edu/newsroom/research/2009/091207KneppSnowflake.html
www.newscientist.com/article/mg20427392.000