EnviroKids October 2018 Issue

Our Beautiful Earth Earth is the third “rock” from the Sun (one of four rocky planets in our solar system), and is the only known planet with life. Scientists estimate Earth to be about 4.5 billion years old. But how does Earth work? Read below and find out more about our beautiful planet.

A Slice of Our Planet

Quick Facts How many countries are there on Earth? 195

The Earth has three main layers: the crust, the mantle and the core . The crust forms the surface and is covered by either soil or water. It is the thin- nest layer (about 30km thick), consisting mainly of solid rock. The mantle is about 2900km thick, while the outer core is about 2254km thick and the inner core is about 1288km thick. The crust is made of rock, soil and

Earth’s Rotation on its Axis Rotation refers the movement the Earth makes on its own axis. This is the imaginary line through the cen- tre of a planet. Earth's axis is tilted at 23.5 degrees. It spins in a clock- wise direction if you look at it di- rectly from the South Pole. It takes our planet 24 hours to rotate, cre- ating one full day for life on Earth.

How many oceans are on Earth? 5

seabed. It is divided into continental plates that drift a few centimeters each year. The mantle makes up 84% of the total weight of the Earth’s mass, and is made up of hard rock, molten rock and solid rock. The outer core is responsi- ble for Earth’s magnetic field, and is made up of molten lava. At the centre of Earth is the inner core. The inner core is hotter than the surface of the Sun.

How many seas are on Earth? 7

What is Earth's atmosphere made of? 78% nitrogen, 21% ox- ygen, 0.9% argon, and 0.03% carbon dioxide with very small per- centages of other ele- ments. A combination of water, oxygen and minerals makes Earth a favourable place for life to grow and evolve. Soil covers much of the land area and provides an anchor for trees, a source of food for plants, and a home for many animals. Water covers about 70% of Earth’s surface, which is why it is called the Blue Planet. About 3% of the water is fresh and the rest is salted.

Earth’s Revolution Around the Sun Every planet revolves (orbits) around the Sun. When Earth orbits around the Sun once, it completes one rev- olution, which is equal to one year (365¼ days). Every four years, these quarters add up to make an extra day which we include as the 29 of February. So how long do the other planets take to revolve around the Sun (in Earth time)? Mercury = 88 days. Venus = 225 days. Mars = 687 days. Jupiter = 12 years. Saturn = 29,5 years. Uranus = 84 years. Nep- tune = 165 years.

What is Earth's radius? 6 371 km

We Used To Be Close... All the continents on Earth used to be joined together, and this “super-continent” was called Pangea. Pangea only started breaking apart around 200-million years ago, to form the separate continents and countries we know today.

What is the population on Earth? 7,6 Billion

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