Can Matter be converted into Energy?

            In 1995 Albert Einstein established a relationship between mass and energy which is known as the mass-energy relation formula. According to this formula if a mass m is converted into energy, then e=mc2 where E is the energy released and C is the velocity of light. According to this formula the energy available by the conversion of half a pound of matter will be equal to that produced by exploding 7 million tones of dynamite.

Atom Bomb converts Matter into Energy

            Scientists realized the real importance of the mass energy relationship in 1945, when the first atom bomb converting uranium into energy was exploded by U.S.A. on 6 august 1945, the uranium atom bomb was dropped on Hiroshima in Japanese. There days later a plutonium atom bomb killed millions of Nagasaki. These bombs killed millions of people. Scientists realized the true potential of unclear energy. Subsequently on the basis of this formula, more powerful hydrogen bombs were developed.

             After seeing the great destruction in Hiroshima and Nagasaki scientists thought of tapping this energy for peaceful purposes. Nuclear power plants have been developed to generate electricity on the basis of this formula. Heat energy produced in reactors by the fission of uranium is used for converting water into steam to run turbines which in turn run generators. These generators produce millions of megawatts of electric power. Einstein mass energy relationship and its subsequent practical applications have proved to be a great boon to mankind. About 1% energy needs of the world are now met by nuclear energy.

Measure the Mass of the Earth

How do we measure the mass of the earth?

            When we wish to know the mass of an object, we weight it in a balance. The size of the balance varies with the size of the object to be weighed. The earth is a giant body and to think of a balance for weighting it, is almost impossible. Then, what is the way of measuring the mass of the earth?

            Scientists use Newton’s law of gravitation to determine earth’s mass. According to this law, there exists a force of attraction between any two bodies in the universe and this is dependent on the masses of the two bodies as well as on the distance between them. The force of attraction is directly proportional to the product of the masses of the two bodies, and inversely proportional to the square of the distance between them.

            An experiment is performed to determine earth’s mass with the help of the above mentioned law. In this experiment, a small metallic ball is suspended with the help of a thin thread. The position of this ball is accurately determined. Now a big lead ball weighing a ton is brought near this ball. The small ball is attracted towards the big ball due to the gravitational pull and as such it is slightly displaced form its initial position with respect to the big ball. The change in the position of the small ball is even less than one-tenth of an inch. This displacement is very accurately measured with the help of precision instruments. Using with the help of displacement in a formula of physics, the mass of the earth is calculated. The mass of the earth has been found to be 598x10¹⁹ (5980, 000,000,000,000,000,000) tones.