Everyone saw the compass. This device, which looks like a regular watch. However, there is one feature. The compass needle always points north. Why? You will find the answer in the article.
Attraction - repulsion
All compasses are devices with a magnet. They work on the principle of attraction of magnetic poles. The light compass needle is a magnet. Our Earth is also a magnet, only very large and not very strong with maximum magnetic field at the poles - North and South. As you know, the opposite magnetic poles are attracted to each other. In this case, the same, on the contrary, are repelled. This is why the compass needle always points north. Briefly, this can be described as follows: a magnetized needle is attracted to the North magnetic pole of the planet.
And more precisely
There is such a thing - magnetic declination. What it is? This is the angle that is formed between the axis of rotation of the planet and its magnetic axis. After all, they do not match. Why does the compass needle always point north? It is difficult to give a short answer, since the question itself is not entirely correct. It is correct to say that the arrow points to a point located north of the pole, namely to Sommerset Island, which is located in the Arctic archipelago of Canada. And from it to the North Pole 2100 km.
First compass
It looked like a bucket with a handle located on a copper plate, in order to find out the cardinal directions, it was necessary to rotate the bucket, and at the moment of its stop the handle pointed to the south. This miracle was invented in ancient China. And the bucket was not chosen by chance. After all, he was copied from the "Heavenly Bucket". That is what the Chinese called the Ursa Major constellation. But then people still did not know why the compass needle always points north. Several centuries passed, and in 1600, Hilbert William, an English physicist and researcher, wrote a book about magnets, magnetic bodies and a large magnet - the Earth. It is he who holds the primacy in the reasoned explanation of why the compass needle always points to the north.
Inaccuracies
But it happens that the compass needle does not always point north. Why? There may be several reasons:
- If other magnets are nearby, they will deflect the compass needle.
- Do not use the compass near electronic devices, as they create electromagnetic fields that distort the readings of the compass.
- During periods of activity on the Sun, magnetic storms (“solar wind”) occur on the planet and they violate the Earth’s magnetic field, and the compass may show the wrong direction.
Zero indicator
Scientists have proven that every two millennia our planet loses its magnetic field. Every 10 years the Earth’s field becomes weaker by 0.5%. When it is gone, the planet will be reversed and the magnetic field will grow again, and the poles will change places. Studying lava deposits, it is proved that this has already happened to our planet more than once.
Compass at home
Make it very simple. To do this, you need a needle, a magnet, a cup of water and oil. The needle should be put for a couple of days near the magnet. Then grease it with oil and carefully lower it into the water in the cup. A magnetized needle in oil will not sink and turn around, indicating the cardinal points.
Bio compass
It turned out that migratory birds have their own compass. Near their eyes there is a small field of sensitive cells in which magnetite is located - a substance that can be magnetized. It is this “compass” that prevents migratory birds from straying from their path.
GPS compass
With the development of satellite communications technology, a conventional compass is a thing of the past. Today, when the coverage of communication satellites practically did not leave unreached areas on the planet, people are switching to satellite navigation technologies. No one is surprised at the navigator in the car and phone. In addition, ships and planes have long used satellite systems for orientation.