Speed and Direction Higher_01

“Set a course for the Canary Islands,” the captain states in a commanding voice. The ship’s navigator feverishly checks the charts and plots a course. The ship is currently off the coast of Liberia, a small country in West Africa. To get to the Canary Islands, the ship must first travel west and then north. The captain checks the navigator’s course and gives the command, “Travel due west at 20 knots.”

The highly trained crew knows precisely what to do. The helmsman, a person who drives the ship, slowly turns the large wheel. The wheel controls the ship’s direction, similar to a steering wheel in a car. He grabs for his sunglasses as the ship turns toward the westerly setting Sun. He shoves the throttle forward to increase the speed of the ship. The engines roar as the ship accelerates or changes speed.

It’s not long until the ship is up to the captain’s requested speed of 20 knots. A knot is a term used for speed, similar to miles per hour in a car. Speed is a term used to describe how fast something is moving. Speed can be determined by taking the distance traveled and dividing that number by the time it takes to get somewhere.

Using his knowledge of mathematics, the ship’s navigator can calculate out how long the trip will take. He knows if they average 20 knots, this journey will take many days. It’s about 1,500 miles from their current location to their destination. Long trips are nothing new to these sailors though.

The navigator is responsible for setting the best course possible. In order to do his job well, the navigator uses a lot of Math and Science. He must ensure the ship avoids danger, such as shallow water or other ships. That means his course may not be a straight line to the destination. He uses his Math skills to plot the course for each segment, or leg, of the journey. Each of the legs may be different in terms of speed and direction.

For this trip, the ship must travel in a westerly direction and then head north from their current position. Currently, the ship is over 100 miles off the coast, so they can’t see any land. How do they determine where they are?