Chloe+W

media type="custom" key="6308863" **__What causes natural disasters?__** Some experts have seen an overall increase in the destructiveness of natural disasters, espescially in the last few decades.

Geologists believe this is the cause of natural disasters: Thermonuclear activity on the centre of the earth, and moving of the earths plates. Naural disasters are caused by two main things, The sun, and the earths core.

The earths core heats the earth, which makes the tetonic plates move, it is colliding up these plates causing earthquakes & tsunamis. There is heat and pressure applied to gaps in these plates that causes volcanic eruption.

The sun creates weather, by heating up sections of the earth, it causes water to evaporate to create rain, and creates wind, the pressure systems. Heat from the sun creates high pressure. The high pressure flows to low pressure, and it is that flow that causes wind. Cyclones are caused when two directions of wind flow next to each other causing a spiral.

**__How was the earth formed?__** The earth was formed in the same way as the sun, stars and other planets. First, the earth was a boiling hot, glowing ball of hot white gases being drawn together and compressed. - this happened millions of years ago. When the earth cooled down, the colour changed from white to yellow to red, to not giving off any light at all. The earth contracted, getting smaller. The gases changed to liquid when they cooled. Heavy materials drew to the centre of the earth, including the liquids.

As the crust cooled, it got wrinkled and burst open in spots. Cracks formed, water that was formed under the earths crust escaped through the cracks and water vapor formed above the earth. - This lead to cloud formation, creating rain. Large droplets formed in the clouds, these droplets were pulled to the earth by gravity, making the first ever rainfall. The rain hit the earth and evaporated straight away. As the earth continued to cool, the rain stayed on the surface, forming lakes and oceans. At first the water was freshwater, but it mixed with the chemicals in the earths crust, making it salty.

Pressure and heat pushed up solid portions of the earth which become land forms.

About 3 million years ago, the earth cooled completely and big sheets of ice called glaciers covered its surface. As the ice spread over the land, it gouged valleys, hills, lakes rivers and other dents in the earth.

About 8000 years ago the last glaciers melted, making the earth more like it is today.

**__Why is earth the only planet we can live on?__** ​Earth is just the right distance from the sun, to be able to facilitate water, food, and suitable warmth. Earth has the efficient atmosphere we need to live. Earth also has oxygen, most planets either have little or none of this substance. The other 8 planets are made up of gases.

**__What is at the centre of the earth?__** The earths core starts 4000 miles down, & its diameter is 6800km. It has 2 layers, " the motten iron outer core" and the "solid inner core" - which is made up of nickel and iron and is roughly the size of the moon. What we're standing on, (the crust) is 1,800 miles of rock.

**__Earth From Space.__** This video shows the earth rotate 360 degrees as seen from space. Made with the 3d space simulator Celestia with hires textures, night side lights, clouds and atmosphere rendering.

media type="custom" key="6286933"