Measuring Altitude

Measuring Altitude with Your Hand

The North Star is an extremely valuable tool for explorers, because it is straight up from the north pole of the Earth and always shows us where north is.

If this way is north, which way is south? East? West? [Point out those directions.] If the North Star is directly over the North Pole, where in the sky would you find the North Star if you were standing at the North Pole? [Straight up.]

As you move southward from the North Pole, the North Star is seen lower and lower in the sky. If we take a journey south for several days, we see the North Star get lower and lower in the sky.

Turn daylight up and down rapidly to simulate days going by, and move the latitude south by a few degrees so that its movement is noticeable.

Where would the North Star appear in the sky if you were at the equator? [On the horizon.]

If we travel northward, will Polaris appear to get higher or lower in the sky? [Higher.] You can use your hands to measure the height of Polaris. Try it.

Demonstrate how to hold hands or fists to make a measurement of the altitude of Polaris. Any way of doing this is fine, as long as you do it the same way every time.

Let’s make a journey of many days. See if you can tell if we have traveled north toward Canada or south toward Mexico.

Turn daylight up and down rapidly to simulate days going by. Move latitude south to about 30° N.

Measure Polaris again with your hand.

Have we gone toward Canada or Mexico? [Mexico.]

Just by using their hands, explorers can tell roughly how far north or south they have traveled.