Category: 7th Grade

Meaning of Satellite A satellite is an object that revolves round another object (which is known as its primary). Satellites can be man-made or may be naturally occurring such as moons, comets, asteroids, planets, stars and even galaxies. An orbit is the path that an object makes around another object while under the influence of a source of centripetal force, such as gravity. Orbits were first analyzed mathematically by Johannes Kepler who formulated his results in his three laws of planetary motion. Isaac Newton demonstrated that Kepler’s laws were derivable from his theory of gravitation and that, in general, the orbits of bodies responding to the force of gravity were conic sections....

The interest of man in space has existed from ancient times when man employed the naked eyes to study and speculate on the moon, the stars, the sun, and other things which were imagined to be there in space. As time went by, man began to carry out more systematic studies of space. By the second century AD, a Greek mathematician called Ptolemy proposed that the earth moved in space. By the 16th century AD, some other scientists such as Tycho Brahe and Kepler had deducted the relationships between the motion of the earth round the sun and the motion of the moon round the earth. In the year 1686, Isaac Newton deduced and published the laws of mechanics. These...

Gravitation is a science concept that lead had been known and understood from Newton’s time. It was he who propounded the laws of universal gravitation from mathematical theory. Since that time, the theory has been used by other scientists in computing various constants and quantities that relate to objects on earth and in space. Gravitational pull is a force of attraction which everybody exerts on every other body. The earth has a large gravitational pull on objects because of its large size. Meaning of Gravitation...

The age we live in is sometimes called the Space Age. It is in this age that the longing of man to reach out beyond the earth changed from wishing to reality. The Universe The Universe is a very expansive space which includes all the stars and our solar system. Our solar system consists of the sun and nine planets which include Mercury, Venus, Earth, Mars, Jupiter, Saturn, and Uranus, Neptune and Pluto and their moons. The light, which reaches the earth, comes from the sun and the stars. The stars are themselves suns with their own solar systems. Light travels at a very high speed. The sky on a bright night seems to be filled with stars. Though each...

This is a force with which the earth attracts objects towards its centre. If you throw a coin up, what do you expect? You will notice that the coin will go up and at a certain point stop before beginning to come down. Is there anything pulling the coin down? Yes, although you may not see anything pulling it. The force due to gravity is pulling the coin to the centre of the earth. Assuming you are holding a mass of 20g in your hand climbing a tree or a high object. Release the mass, what do you notice? You will notice that the weight did not go horizontally but vertically....