Ekadvitricatuhpancasarvatomukhameva tat |
Meaning: Magnets are of 5 varities – Bhramakam, Chumbakam, Karshakam, Dravakam and Romakantam. They again are single faced, double faced, three faced, four faced, five faced and multi faced. Each is again in three colours – yellow, black and red.
Source: Rasarnavam, Patalah 6, Adhyayah 40, Slokah 21 (12th century AD)
It was in the eighteenth century that magnets and its principle was better understood by the world. Our Ancient Indians used magnets extensively in many fields. They divided magnets into five categories namely Bhramakam, Chumbakam, Karshakam, Dravakam and Romakantam. This classification was made based on the variety of the magnet. They were further sub classified based on the structure as single faced, double faced, three faced, four faced, five faced and multi-faced. These magnets had three predominant colours i.e. yellow, black and red.
Magnets have excellent properties, thus they were broadly used in medical treatments, construction of monuments, vehicles etc. It is really amazing how the ancient people recognized such wonderful phenomena in those early days.
The ancient vedas and ancient scientists considered polarity to be present in every human being. Bhattacharya also worked on magnets and effects of magnetism on human beings. After Bhattacharya, it was his son A.K.Bhattacharya, who took forward his father’s work and extended it widely to the medical field.
Medical therapy involved usage of magnets since they had a lot of earthly forces which could calm down the body temperatures. And the famous Ancient Indian physicist, Sushrutha, used magnets for surgeries because of its antiseptic properties. It was also used for spinal treatments and for healing wounds.
According to the modern theory, materials are classified into three categories based on the strength of magnetic field. They are: Para-magnetic substances, Ferro-magnetic substances and Diamagnetic substances. Para-magnetic substances have medium magnetism, Ferromagnetic substances have strong magnetic field and diamagnetic substances have zero magnetic field.
Some of the examples for each are:-
Ferro-magnetic substance– Iron (Fe), Nickel (Ni), cobalt (Co)
Para-magnetic substance– Aluminium (Al), Copper (Cu), Manganese (Mn)
The Domain theory is used to explain the internal structure of magnets wherein magnets are divided into domains. Domains are nothing but small regions inside the magnets which have atoms in the direction of the magnetic field. So one domain may have a particular direction which may be different in the other domain.
Properties of magnets
- Magnets have two poles i.e. North Pole and South Pole. Even if the magnets are further broken into pieces, each tiny piece will have a North and a South Pole.
- Like poles always repel and unlike poles attract.
- Magnetic field is not visible but it can just be felt. And the field between North and South Poles is circular or elliptical, which is again imaginary.
- Magnets expand laterally and contract longitudinally.