SCIENCE LESSON NOTES
SLIDE ONE-STRUCTURE OF THE EARTH
The inner core is in the centre and is the hottest part of the Earth. It’s solid and made up of iron and nickel with temperatures of up to 5,500°C. With its immense heat energy.
The outer core is the layer surrounding the inner core. It’s a liquid layer, made up of iron and nickel and it’s extremely hot similar to the inner core.
The mantle is the widest section of the Earth. It has a thickness of approximately 2,900 km. The mantle is made up of semi-molten rock called magma. In the upper parts of the mantle the rock is hard, but lower down the rock is soft and beginning to melt.
The crust is the outer layer of the earth. It’s very thin and the solid rock layer upon which we live.
SLIDE TWO-LITHOSPHERE
The Earth's lithosphere is a rigid outside layer that’s made up of the crust and mantle and it’s made up of a mixture of minerals. The rocks in the lithosphere are made up of mostly silicates. These are compounds that contain silicon, oxygen and smaller amounts of other elements.
SLIDE THREE-TECTONIC PLATES The Earth's crust is broken up into pieces called plates. Heat rising and falling inside the mantle creates convection currents generated by radioactive decay in the core. The convection currents move the plates. And where convection currents diverge near the Earth's crust, plates move apart.
Where convection currents converge, plates move towards each other. The movement of the plates, and the activity inside the Earth, is called plate tectonics. Plate tectonics cause earthquakes and volcanoes. The point where two plates meet is called a plate boundary.
Earthquakes and volcanoes are most likely to occur either on or near plate boundaries.
SLIDE FOUR-VOLCANOS AND EARTHQUAKES
At a tensional or constructive boundary, the plates are moving apart because of convection currents inside the earth.
As the plates move