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Create a Compass
Walk 10 blocks north. Drive three miles east. Fly two hours south. We rely on directions every day to get where we need to go. Without knowing north, south, east, and west, we would be lost!
But what do these directions mean? North is the direction that points from where you are to the Earth's North Pole. We can find north by looking at stars and constellations. We can also find north with a compass. From any place on Earth, a compass will always point north. And once you find north, you can figure out which way is south, east, and west.
Why does a compass point north? That's because a compass is a small magnet. And a compass works because the Earth also acts like one giant magnet! Deep below the Earth's surface is the Earth's core, made of iron and nickel. The outer part of the core is liquid metal that moves around the solid inner core. This motion creates a magnetic field around the Earth. Like all magnets, the Earth has two poles. The magnetic needle on a compass will always point toward the North Pole.
The Chinese invented the first compass more than 2,000 years ago.
A modern-day compass.
See if you can find north by making your own compass.
The Materials
- Sewing needle (about 1 inch long)
- Small bar magnet (refrigerator magnets will also work)
- Piece of foam (from an arts and crafts store)
- Scissors
- Small bowl of water
- Real compass
What to Do
Cut out a small cube of foam, about 1/2 inch long on each side.
Lay the needle flat against the magnet. Then rub the magnet one way against the needle. Do this 20 times, making sure you always run the magnet in the same direction. This will make your needle magnetic.
Stick the needle all the way through your piece of foam. Have an adult help you and be careful not to prick yourself!
Float the foam and needle in your glass of water. The needle should lie parallel to the surface of the water. The glass, water, foam, and needle all together make up your compass!
Place your compass on a flat surface and watch what happens. The needle should turn until one end points north and the other end points south. (Your needle is pointing toward the North Pole!)
Now place the bar magnet close to you compass. What happens? Try moving it closer and farther away. How close does the magnet have to be to have an effect on your compass?
Try this!
Here are some ways to try out your compass:
- Find a map showing the streets of your neighborhood. Go outside and turn your map so it matches the streets. What direction is north? Now look at your compass. Is that the direction your compass is pointing?
- After the sun sets in the evening, use your compass to find the star called Polaris. This bright star is also called the North Star because it is always directly north in the night sky. If you need help, look for the Big Dipper. The two stars at the end of the dipper point to the North Star. In the picture below, the Big Dipper is circled in blue and the North Star is circled in red.
Image Credits:
Big Dipper and Polaris, courtesy of Jim Thomas, CC BY-SA 3.0, via Wikimedia Commons; all other images, © AMNH.