Grade 4, term 4, Natural Science, Planet Earth

The Earth is round like a ball (sphere) and is made of rock. Earth is a mixture of various eco-systems that supports life for many creatures, because the Earth has many different habitats for living things.

So, the rocks on the surface of the Earth, could be underwater, covered with vegetation or exposed (mountain). The land we can see out of the water is made up of continents and islands. Continents are large land masses, and islands are small pieces of land surrounded by ocean.

Most of the surface of the Earth is covered with water (oceans and seas). Water is the most precious resource on Earth. Earth is known as the Blue planet, because from space, the Earth looks blue. Without water, life would not exist. 97 % of the Earths water is in the ocean which is salty. 2 % of the water is frozen up in glaciers and ice caps, 1 % is fresh water.

Saltwater cannot be used as drinking water or water for irrigation. Because the saltwater will kill most plants, and cause dehydration in animals and humans.

Oxygen makes up one fifth of the atmosphere and is an important element for life, because most living things need it to survive.