COntents 4-5 LAYER ON LAYER Layers Pangaea Tectonic plates 6-7 A GIANT MAGNET Metal at the center Magnetic field Gravity Magnetic poles 8-9 DIFFERENT ROCKS Sedimentary rock Strata you can see Rock time 10-11 VOLCANOES Igneous rock Metamorphic rock 12-13 WEARING AWAY Weathering The rock cycle 14-15 THE ERODERS The power of wind The power of ice The power of water 16-17 ROCKS IN SPACE Rocky planets The Milky Way The Kuiper Belt The Oort Cloud 18-19 CRASH LANDING Meteors and meteorites Comets 22-23 CAVES Prehistoric shelters Painted walls Troglodytes Petra cave city 24-25 ROCK DEEP Stalactites and stalagmites Rock shelters 20-21 FOSSILS Ammonites Fossils Animal skeletons Huge fossils Plant fossils
26-27 EARTHQUAKES Shaking rocks Help at hand Measuring the quake Seismology 28-29 MOUNTAINS Mountain ranges The highest mountain 30-31 UP AND DOWN Mountains and valleys Tree and snow lines Mountaineering Sherpa guides 32-33 ROCKY ROADS Alpine roads Blasting the rock Road tunnels Cobblestones 34-35 TINY PIECES Gravel pits Sand Soil 36-37 BUILDING MATERIALS Cement Slates on the roof Concrete Marble Limestone Foundations Bricks 38-39 ROCKS TELL HISTORY Pictures in stone Ancient inscriptions 40-41 STONE MEMORIALS Obelisks Faces in the cliff 42-43 OLD BUILDINGS Pyramids Ziggurats Pyramids of Mexico Mycenae Roman theaters The Parthenon Roman arches 44-45 UNDERGROUND FUEL Starting with carbon Oil Refining Natural gas 46-47 GEOTHERMAL ENERGY Geothermal energy Geysers 48-49 MINING Mining Mining ore Ores Making steel 50-51 PRECIOUS ROCKS Cutting and polishing Precious stones Semi precious stones Making jewellery Working diamonds 52-53 ROCKS AND ART Pavement art Graffiti Pencil art Pigments Chalk 54-55 ROCK SCULPTURE The terracotta army Lifelike in stone Giants 56-57 ROCKS IN THE HOME Pestle and mortar Sharpening stone Emery smooth Pumice stone A rock on a string Mud bath 58-59 GAMES WITH ROCKS Jacks Hopscotch Seven stones Mankala Go Skimming GLOSSARY and INDEX
4 Layer On layer The crust is up to 40,3 miles thick The upper mantle is 447 3 miles thick The lower mantle is 1348,9 miles thick The inner core is 758,6 miles thick The outer core is 1403,6 miles thick Our Earth is the rock on which we live It may seem pretty stable when we’re standing on it but it’s not a solid piece of rock In fact some of it is a churning boiling mass of red hot liquid rock that is constantly on the move We may only see the rocky crust but there’s lots going on inside Layers When you stand on hard ground you might think that the planet youTre standing on is one solid ball But it isnTt ItTs made up of layers The hard bit you stand on is the outer layer called the crust Underneath is the upper mantle a plastic-like solid that is actually close to melting point Below that is the lower mantle of dense mostly solid rock Scientists think the core is made of solidly-packed metals The liquid outer core is mainly iron and nickel while the solid inner core is mainly iron The temperature here is around 10,832ºF at the core but the weight of the layers above presses the material together so hard that it has become solid
Pangaea WeTre used to seeing the continents on maps in a fixed position But the continents arenTt fixed at all At one time 225 million years ago the continents made up just one great landmass Scientists call this landmass Pangaea or all EarthT Around 100 million years ago the continents began to split apart Forty million years ago they looked pretty much as they do today 5 KEY WORDS crust core mantle iron nickel tectonic plate continent 225 million years ago the Earth’s continents were starting to break away from the single landmass known as Pangaea Over millions of years the continents split apart Today the continents form the familiar shapes we see in atlases TectOnic plates The continents split apart because they are part of the ever-moving jigsaw of plates that make up the EarthTs crust These plates known as tectonic plates can collide into one another move apart from one another or slide past each other At one of its edges where plates are moving apart a plate can grow as magma rises up out of the mantle below At the same time another edge is destroyed either by sinking down under its neighbour plate or by being pushed up to make mountain chains 8 to 12 large plates and about 20 smaller ones make up the EarthTs crust
