Category Archives: Just for Fun

More Math on NPR: Babbage’s Difference Engine

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This 5 minute segment was a part of yesterday’s All Things Considered, on NPR. Go listen to it! Charles Babbage invented the computer in the 19th century, long before vacuum tubes or transistors were even invented. He called it the “Difference Engine.” He drew plans for an intricate machine — a large and powerful (but purely mechanical) computer but his plans were never fully executed.

This was also the subject of a WIRED magazine interview in 2008:

So next time you want to evaluate a 7th degree polynomial, why not give Babbage’s difference engine a spin? 🙂

Derivative Books

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Allow me to introduce you to my Calculus class! Here, they show you a few of their “Derivative Books.” As a fun reference guide, students made small origami books and wrote derivative rules on each page. On the front, they made enticing covers, a few of which you see here:

I encourage you to keep a book like this in your back pocket, or in your wallet. You never know when you might need to take a derivative!

RadioLab is Speaking our Language

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Here’s a great episode on Numbers, produced by NPR’s RadioLab. It’s an hour long, but you can download a podcast, or listen to it as you work. I learned some interesting stuff!

One new mathematical fact I learned was that the locus of points 1 unit away from an elipse is not an elipse. I’m going to work on the proof. Fascinating!

(Thanks, Drew, for pointing this out to me!)

 

Einstein’s Puzzle (Answer)

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Okay, don’t read any further unless you’ve already tried the puzzle. It’s a classic logic puzzle and can be solved by the standard grid-technique, like commentors suggested. I did the same thing, and I got this answer:

The German owns the fish.

Did you get that too? Here’s the thing: It’s technically not correct, according to a few sources I found. Some people say the correct answer to this problem is “there’s not enough information; the fish isn’t even mentioned in the listed facts.” I’m not sure what I think, but it gives some food for thought. Consider the following new problem and you’ll see why:
Who is the American?
(Fact 1) Winston and Paul are of two different nationalities
(Fact 2) Paul is Canadian.
What do you think? Would you say “Winston” or would you say “Winston could be anything (except Canadian) given the facts”? If you say “Winston” then you’re actually assuming a third fact: One of them is an American.
In the case of Einstein’s Puzzle, we technically need a 16th fact: One of them owns a fish.
So what do you think? Those of us who solved the puzzle in the classic logic-problem grid-solution way simply assumed that fact and got on with our lives. But what do you think? Do you think we can assume that someone owns the fish even though it’s technically not a “fact?” It’s an interesting issue–perhaps just a linguistic one. Let me know what you think.