A Million Pennies

Like my earlier post on the Robinson’s Land Regeneration Scheme, this one is about an Ahaa! moment when a nice bit of mathematics hits you and you think: “That would make a great teaching idea.”

While browsing through an old magazine recently I came across a short article that had a link to a website that explored what a million pennies might look like. I typed the link into my browser, half expecting to see that the website had been closed down sometime in the 1990′s, but – to my surprise – there it was in all it’s glory. A little old-fashioned, but still, a great starting point for a bit of meaningful maths. The website is The MegaPenny Project and it was designed to help people visualise large numbers.

There is no arguing with the fact that visualizing large numbers can be very difficult. People often talk about thousands of miles, millions of pounds (GBP) or Dollars, for example, yet it’s still hard to conceive exactly how much a “million” really is.

The MegaPenny Project takes an everyday item, the U.S. penny, and uses cartoon images to help demonstrate: “What a billion (or a trillion) pennies look like?”

Here are three of those images together with the information as given on the MegaPenny website (click the tabs):

• 1 cent
• 1000 cents
• 1 million cents

• 1 cent

  

   

  width     0.75 inches, (3/4 of an inch)
  height     0.75 inches, (3/4 of an inch)
  thickness     0.0625 inches, (1/16 of an inch)
  weight     0.1 ounces, (1/10 of an ounce)
  area     0.5625 square inches

• 

   

  width      3.75 inches
  height      3.75 inches
  thickness      2.5 inches
  weight      100 ounces, (6.25 pounds)
  height stacked      62.4 inches, (5.2 feet)
  area (laid flat)      562.5 square inches (3.9 square feet)

• 

  width      Four feet
  height      Five feet
  thickness      12 inches, (one foot)
  weight      6273.6 pounds (3.14 tons)
  height stacked      5,228 feet ( 0.99 Miles )
  area (laid flat)      3,921 square feet

   

Now, I loved the concept. I also liked the idea that it used American currency and non-metric measures. Since this meant that I could show it to my class here in the UK and ask them if they could do something similar with our own currency.

As a starting point we would need to accurately measure and weigh a UK 1p. Then we could start calculating!

My children estimated, weighed and measured. Since it was tricky to accurately measure one penny we weighed 10 and divided. The we checked online!

1 UK Penny (sterling) weighs 3.56 grams and is 20.3 mm in diameter.

10 pennies would weigh 35.6 grams and if placed in a line would measure 203 mm.

All of which led to more questions:

My thanks to the MegaPenny website for offering the original inspiration for this idea: www.kokogiak.com/megapenny/