Most globes and maps
of Earth are marked with latitude lines, imaginary lines that circle the
globe, running parallel with the equator. Geographers use latitude to
say how far north or south of the equator a place is.
On a clear night,
people can figure out their latitude by using their inclinometers. First,
they need to find the North Star (also known as Polaris). The easiest
way to find the North Star is to find the Big Dipper. An arrow drawn through
the two stars that form the end of the Big Dipper's bowl points to the
North Star, which is at the end of the handle of the Little Dipper. The
North Star is always located between the Big Dipper and the constellation
Cassiopeia. In the Northern Hemisphere, these constellations never set.
Like the North Star, they are always in the sky on a clear night.
To figure out their
latitude, people need to sight on the North Star with their inclinometers.
The height of the North Star, in degrees, is their latitude. The North
Pole is at 90 degrees north latitude. Someone standing at the North Pole
would have to look straight up to see the North Star.
You might consider having people take their inclinometers home and measure the height of the North Star. Their answers should all be about the same. Check your latitude on a globe or a map to confirm their measurements. The latitude of San Francisco, California, is about 38 degrees north.