ROCKS MINERALS AND FOSSILS crust solid rock Rock is the natural substance that the Earth is made of On the Earth’s surface or crust rocks are mostly solid and hard The inside of the Earth is very hot at around 7,200 F 4,000 C and the rock here called the mantle is partly melted flint mantle partly melted rock outer core liquid iron inner core solid iron chalk basalt sandstone The Earth’s crust is made up of many types of rocks 4
MINERALS Rocks are made up of minerals Some rocks only contain one mineral Others contain mixtures of minerals A mineral is a pure natural substance from the ground This means it’s the same all the way through it’s not a mixture of different things Minerals include some metals such as iron and gold and gemstones such as diamonds and quartz Granite is a rock made up of a mixture of minerals including quartz feldspar and mica THE ROCK CYCLE Rivers and seas wear down rocks creating valleys and coastal cliffs Old rocks wear down crack apart and break up into sand dust and silt New rocks form from sand and mud on the seabed Volcanoes throw out lava melted rock which hardens to make new rock Earthquakes crush move and crack rocks This process of rocks breaking down and forming again is called the rock cycle A rock stone or pebble might seem like a very hard long-lasting object that doesn’t change much But over long periods of time Earth’s rocks change a lot ROCKS AND HUMANS Rocks are incredibly important to humans Besides living our whole lives on the Earth’s rocky crust we dig up all kinds of rocks and minerals to make many of the things we need FINDING FOSSILS Rocks also hold a record of life in the past in the form of fossils Fossils are made when rocks form around the remains or imprints of living things Over time the animal or plant material is replaced by rocks and minerals but the shape of the creature can still be seen This is a fossilized trilobite a type of animal that lived from around 520 million to 250 million years ago 5
THE SCIENCE OF ROCKS AND FOSSILS Besides using rocks we also study them to try to find out more about them This is the science of rocks The word science simply means knowledge so science means trying to learn about things and understand them There are many branches of science to do with rocks minerals and fossils Together they are known as the Earth sciences Studying and understanding these things helps us in all kinds of ways Geology is the science of rocks and the way they form the Earth Studying them reveals how the Earth has changed over time to become what it is now It also helps us to figure out where useful rocks and minerals can be found Volcanology is the science of volcanoes and seismology is the science of earthquakes By studying them and how they work scientists can often predict volcanic eruptions earthquakes and landslides and help to save lives Mineralogy is the study of minerals and how they can be used newest rocks contain the youngest fossils Palaeontology pay-lee-on-tol-ogy is the study of fossils which helps us to understand the history of life on Earth time oldest rocks contain the oldest fossils 6
WORKING SCIENTIFICALLY This book contains experiments and investigations that will help you find out more about rocks and fossils To do experiments scientists use careful logical methods to make sure they get reliable results The experiments in this book use four key scientific methods along with an easy acronym to help you remember them ATOM ASK What do you want to find out Asking questions is an important part of science Scientists think about what questions they have and how to find answers OBSERVE Key things to look out for Scientists watch their experiments closely to see what is happening WHAT NEXT After each experiment the What Next section gives you ideas for further activities and experiments or ways to display your results TEST Setting up an experiment that will test ideas and answer questions Scientists design experiments to answer questions Tests work best if you only test for one thing at a time MEASURE Measuring and recording results such as temperatures sizes or amounts of time Making accurate measurements and recording the results shows what the experiment has revealed 7
