Real Pirates and How to Make a Compass

 - by KitchenPantryScientist

Last week at the Real Pirates exhibit at the Science Museum of Minnesota, I walked below deck on a mock pirate ship, hoisted a pirate flag (Jolly Roger), touched real pirate treasure and played dice with pirates.  The bell of the Whydah, a 300-ton pirate ship greeted us, illuminated by lighting and suspended in a huge tank of water. I could almost imagine it spinning and tumbling to the bottom of  the sea off the Massachusetts coast. 146 people aboard the ship drowned when The Wyhdah went down.

I was lucky enought to meet the treasure hunter-turned-historian Barry Cifford who discovered the wreck of the Whydah. He explained to us that pirate ships were true democracies, where crew mates were equal, no matter their background, age, race or religion. As a result ,many rushed to be pirates- whether they had escaped slavery, unjust society, or were just trying to make their fortune. The captain of the Whydah, Sam Bellamy, needed money to marry the woman he loved.  There was even a 10-year old boy named John King aboard the Whydah when she went down…he left his mother to join the pirates. (My 11-year old claims he’d never do that.)

How did pirates navigate their way around the deep blue ocean well enough to ever utter the words “Land Ahoy?” In addition to maps and the stars, they used tools like the ones I saw from the Whydah: sounding weights to determine sea depth and ring dials to tell time. They also used compasses, simple tools for determining which direction North was, even in thick fog. A compass is an instrument containing a magnetized pointer that shows the direction of magnetic north, and you can easily make one with a needle, a magnet  and a piece of cork or Styrofoam and a  glass bowl (or pie plate) containing a few inches of water.Cut a slice of cork, maybe 1/2 inch thick) with a bread knife (see photo.) Then, magnify the metal in your needle by stroking it from one end to another with a magnet about ten times. (Go the same direction each time.) Push your needle through the cork or Styrofoam and gently set it in the bowl of water.  The needle, which you have turned into a magnet, will line up with Earth’s magnetic field, which runs from the South Pole to the North Pole. It should point North and South if you magnetized it correctly!

Scientists believe that because Earth’s core, or center, is made mostly of molten (melted) iron, that it generates an magnetic field.

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