String us along
Mr Morley, thanks for the larf, but there’s no way the string would be only 628 mm longer going around the Earth.
Try a little experiment: Get a piece of string, then wrap it ‘round your waist, like it was holding up your King Gees. Take note of how many centimetres of string are needed. Now, remove the string and go on a spree of burgers, beer, pizzas, ice cream... whatever you want to scoff down for one month.
Now, get that string out again and wrap it around your belly like you did a month prior and check how many cm you need. How many? Five or six centimetres extra? If you need that much extra string just to go round your expanded waistline, imagine how many extra cm you would need to go around the expanded Earthline.
Peter,
Narwee, NSW
Morley Says
HAVE YOU been watching me through my kitchen window or something, Pete? How do you know so much about my dietary habits? This is spooky. Actually, The Speaker of the House won’t let me get away with any culinary terrorism, so expansion in my girth is largely down to our old friend Mr Beery-Pop. But I digress. Anyway, bud, I’m sorry to tell you that you’re wrong and I’m right: The extra 628mm is, in fact, precisely the amount of extra string you’d need to circumnavigate the planet after a 20mm expansion of its diameter. I know, it still does my head in too. Apparently, it’s all down to the circumference of a circle (or sphere) being locked in a non-negotiable relationship with its radius (and, therefore, its diameter) and our other old mate Pi. (Beer and Pi(e)s. Mmmmmm.) And here’s where it gets really trippy: It doesn’t matter whether you add 20mm to the diameter of a bowling ball, the sun, or something half-way in between (like, Kanye West’s head) the extra string required to circumnavigate it will always be 628mm.
“THE EXTRA STRING REQUIRED WILL ALWAYS BE 628MM. WEIRD, HUH?”
Weird, huh? But don’t tear yourself up over this, Pete. You’re definitely not the only bloke contacting me to take issue with this brain-teaser. But I’m sticking with my statement. I reckon the real magic of this whole thing is that it’s so anti-intuitive. Experience has taught us that big things need big amounts of stuff to cover or wrap them. As we already know that walking around the planet would not be completed before lunchtime, it’s safe to assume that adding anything to that diameter would blow the circumference out of the water. Big mistake. Remember the old popquiz at school: What weighs more, a ton of feathers or a ton of bricks? Of course, the answer is: Neither – they both weigh a ton. Or, remember: A plane crashes into a hill. On which side of the hill do they bury the survivors? Um, it’s not the survivors they bury, right? We can take this a step further, too. Say you’re trying to track down a mis-fire in your Sunday car. You’ve changed the plugs but it’s still running on five. So you start changing more and more things until you’ve rebuilt the damn thing and it still won’t rev out cleanly. What made you so certain you really knew what you knew? Is it not possible that you got sold a dud spark plug? Did you swap the plugs around and see if the dead cylinder moved with the plug? Nope, you assumed it was stale fuel, carby, fuel filter, points, condenser, leads and, finally, a blown head gasket. And now you’re standing in a shed with your engine pulled apart and tears running down your grimy little cheeks. I know I’ve been there. The point is that we shouldn’t be too quick to jump to a conclusion that seems right, even if the theory has proven correct in the past. Because, this time, it might not be. As a wise old mechanic told me: When we assume, we make an ASS of U and ME.