When a pin is placed vertically in the surface of water, it will surely sink because it pierces the water. The pressure on the small surface of the water is not big enough to enable the pin to float. But if the pin is placed horizontally, a bigger area of water surrounding the pin is covered enabling the pin to float.
This is because the forces between the water molecules underwater and around the straight pin are wide enough to balance the pin on the water holding it to float. Even in this modern day, many people still consider the science of magnetism as mysterious.
The magnetosphere of the earth explains the interaction of the earth’s magnetism to the solar wind and magnetic phenomenon on the sun’s surface. In ancient history, the Greeks and Chinese were aware about the existence of natural magnets coming from iron-rich mineral called lodestones.
The Chinese people were aware that if you rub a metal pin with a lodestone in one direction, the metal pin will also become a magnet. It was also later discovered that if a magnet or lodestone is put on a small boat floating in a container of water as an experiment, the magnet will always point in one direction which is either the North or the South.
If you rotate the container in any direction, the magnet will still point in one direction. A wire coil wrapped in iron bar which has current becomes a magnet. If you use a magnet to attract a group of nails, all the nails will stick to the magnet and each nail will stick to each other afterwards.
Soft iron tends to become a magnet when rubbed in a magnet and its polarity is fixed in one direction which enables it to adhere to another nail. As we all know, the earth is the largest magnetic sphere and it is the great source of magnetic compass.
If you come to think of it, if the power of lodestones was not discovered, it would be impossible to discover the magnetic compass. In this connection, Columbus would not have succeeded in his expedition in foreign lands without the small and simple equipment known as compass.
Going back to the floating pin, if you try to experiment it in a container of water, you must use the thinnest size of a pin measuring about 3 cm; heavier than this can cause the pin to sink. The pin should be dry and holding it adds up to its floating ability as it gets some grease from your fingers.
Strike it with a magnet in one direction and you will notice that when you place it on the surface horizontally, it will float but points to one direction either to the North or the South as you verify in your compass.
Why does it float then? Floating is possible for the pin because the thin skin of the layers of water molecules above the water surface will adhere together to form a blockade that prevents the pin from sinking.