Floating Magnetic Compass | English

A Floating Magnetic Compass

Dear friends, today we are making a floating magnetic compass by using very simple materials. First, let’s understand what a magnetic compass is. A magnetic compass is a device that indicates the directions. It is one of the most important instruments for navigation that responds in the presence of magnetic fields. You can make your own magnetic compass that can float in the water and also show the north and south directions. For this, we need very simple materials like strong magnets, needles, Styrofoam balls, a bowl of water, and a magnetic compass.

Take a strong magnet and rub it on the needle several times using the single touch method. First, let us understand what the single touch method of magnetization is. The single-touch method is one of several methods of making a magnetic material like soft iron into a magnet. In this method, one end of the magnet, say, the North Pole, is placed at one end of the needle, which is then rubbed over the needle from the end to another end, and then lifted and brought back to the first end.

After rubbing a strong magnet several times on the needle, it gets magnetized. As you know, the needle is made from iron. Let's understand how an iron needle gets converted into a magnet. A magnetic material like iron doesn't behave like a magnet because the domains don't have a preferred direction of alignment. On the other hand, the domains of a magnet (or a magnetized iron) are all aligned in a specific direction. In our activity, initially, the domain of the needle was not aligned. When you rubbed the magnet on the needle, the domain of the needle got aligned and the needle was converted into a magnet.

After converting the regular needle into the magnet, take two Styrofoam balls and insert the needle into them so that the needle can easily float on the surface of the water. Here we are using the Styrofoam balls as floaters. If you don’t have Styrofoam balls, then you can use any lighter material that can float in the water. Now place the needle in the water bowl and observe the direction of the magnetic needle. After some time, the needle moves in such a way that it always points in the north and south directions.

Then the question will come to your mind: why does the magnetic needle show the north and south directions? As we know, all magnets have two poles, a north pole and a south pole, and the north pole of one magnet is attracted to the south pole of another magnet and vice-versa. Our earth also has magnetic poles that are closer to the geographic poles of the earth, so the magnetic poles of the compass needle are always attracted towards the magnetic poles of the earth. Hence, the magnetic needle always shows the north and south directions. Here you can check the actual direction of our floating magnetic needle with a magnetic compass.

I hope everyone will like this experiment, and you can make your own floating compass.

Thank you very much.

Team: Prof. Harinath Chakrapani, Dr Sourabh Dube, Dr Aparna Deshpande, Shubhangi Wankhede, Ashok Rupner, Dr Neeraja Dashaputre, Dr Chaitanya Mungi, Ankish Tirpude, Shraddha Bhurkunde, Dinesh Turkar, Pradnya Pujari, Sakhee Bhure, Dr Apurva Barve, Dr Asim Auti, Shanti Pise, Rohit Piwal and Science media centre team of IISER Pune.