Mercury is very hot during the day and very cold at night. It is also the fastest planet in the Solar system. Venus is the hottest planet in the solar system. One of its volcanoes, Mat and
Olympia's Mons, is named after the Egyptian god of truth and justice. The beautiful blue color
of Earth comes from the oceans which cover 70 per cent of the planet. More than seven billion
people live there. The fourth planet, Mars, is named for the Roman god of war. Until 1976
scientists believed there could be life on Mars. Jupiter is the largest planet that we know of. It is
a very stormy planet because it spins so fast. Saturn is 100 times the size of Earth, but it is even
lighter than water, so it would float in a gigantic swimming pool? Uranus is strange because it
spins at an angle. Each pole of Uranus, north and south, has 42 years of sunlight, then 42 years of
darkness. Neptune takes more than 160 years to go round the sun. It has the strongest winds in
the solar system - up to 2 400 kph. Pluto is not considered as planet anymore because of its
strange orbit.
True or False
1. People believe there is life on the planet Mars.
2. Earth is much lighter than Saturn.
3. The planet nearest to the sun is very hot at night.
4. Neptune is usually farther from the sun than Pluto.
5. After every 84 years the north pole of Uranus has light.
6. Pluto is a planet with very strange orbit.
In 1869 the great Russian scientist Dmitri Mendeleyev announced the discovery of the Periodic Law of elements. So science received the key to the secrets of matter.
All the greatest discoveries which have been made since then in the fields of chemistry and physics have been based on this law.
The elements in Mendeleyevs Periodic Table follow one another in the order of their atomic weights. They are arranged in periods and groups.
Mendeleyev s discovery made it possible for the scientists to find 38 new chemical elements to fill the empty spaces left in the Periodic Table.
At the same time they tried to find elements heavier than the last element in the Periodic Table.
In 1955 the American scientist Dr. Glenn Seabord obtained element No 101 and named it Mendelevium in honour of the creator of the Periodic Law.