For all their variety and variation, cities are, at their root, physical systems. That means, at some fundamental level, they are also expressions of the laws of physics. In physics size matters (or "scale" as we call it). Physicists learn different things about an object by looking at it from different scales. In our first exploration of physics and cities we stayed at the street level. At that scale we saw cities as machines: cars and elevators, pipes and plumbing. Then we went up to the roof. At that scale we saw cities as engines, vast systems for turning energy into work.
On her 22nd birthday this summer, Sarah Wagner of suburban Wheaton, Ill., who describes herself as a huge fan of the Chicago Cubs, opened an email to find an incredible surprise — a recorded message from her favorite Cubs player:
"Hey, Sarah! Kerry Wood here! Thanks for your message and I hope you're having a great summer!"
"When I heard for the first time, I instantly smiled," says Wagner. "I think my hands probably went over like my mouth, like, 'Oh my gosh, Kerry Wood is talking to me, even though he has no idea who I am!' "
Each week, All Things Considered and Lenore Skenazy, author of the book and blog Free Range Kids, bring you "Another Thing," an on-air puzzle to test your cleverness skills. We take a trend in the news and challenge you to help us satirize it with a song title, a movie name or something else wacky.
This week's challenge: A study out of Norway found that couples who split the chores equally are 50 percent more likely to divorce.
In the five days since Republican presidential nominee Mitt Romney was declared by many the winner of the first presidential debate, political watchers have waited to see if polls would shift in response to his performance. And, they did.