Two Ditches

Where things come from · Page 1 of 2

Name Date
DIRECTIONS: Most things arrive by ship, and twice people changed the shape of the water. Work out the distances.
Distances are measured on the globe, not a flat map.
Shanghai to RotterdamHow far
through the Suez Canal17,505 km
the other way, round the bottom of Africa23,119 km
what the canal saves5,614 km  (24%)
New York to San FranciscoHow far
through the Panama Canal8,917 km
the other way, round the bottom of South America22,404 km
what the canal saves13,487 km  (60%)
Now the number that ought to stop you. New York and San Francisco are 4,127 km apart across the land. A ship going between them through the canal travels 8,917 km — more than twice as far as the country is wide — and that is the short way.

Both canals are roughly a hundred miles long. Neither is impressive to look at. Each one is worth thousands of kilometers to every ship that uses it, for ever.
  1. Work out roughly how many days each canal saves, if a ship does about 700 km a day. Both answers.

Two Ditches — One Point of Failure

Where things come from · Page 2 of 2

A shortcut everybody uses is a place everybody can be stopped: one stuck ship closes a canal.
  1. The Panama Canal saves a much bigger share of the journey than Suez does. Look at where each one is and say why.
  2. A ship gets stuck sideways and blocks the Suez Canal for a week. Using sheet 10, say what that does to a factory four thousand miles away — and why it is not simply "things arrive late".
  3. Somebody says a canal is just a convenience. Using your day counts, say what you would tell them.