Deconstructing April Fool’s Day

Okay, I admit it – my previous blog post was published on April 1. The foundations of mathematics are not really under attack, not now. But they were once!

Here’s a famous puzzle: imagine a village barber, who cuts the hair of everyone who doesn’t cut their own hair. Sounds simple enough, but who cuts the barber’s hair?

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What Is Counting?

My son asked me a riddle this afternoon – “What goes up but never down?”

I said “An elevator!”

He seemed surprised by my answer, so I said “Voyager I!”

Then he complained that the riddle was so generic, there were millions of possible answers. I asked him if there was some traditional answer I was supposed to give, and he said that he didn’t know of one.

Do you?

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Solar Powered Saffron

My solar panels have generated 1500 kWh of energy since they were installed 6 months ago.

Now, Einstein tells us that energy has mass. How heavy is 1500 kWh? We can use E = mc2 to find out.

Here, E is 1500 kWh, the speed of light c is 186000 miles/second. Unfortunately, we can’t just divide 1500 by the square of 186000. Sure, that would give the mass, but not in any unit I’m familiar with – when you tell me how much something weighs, I want to hear it in pounds, or kilograms, or ounces… even centiweight would do, if I have Google handy.
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