PoGKS FORM THE HARD Ol/TER CRI/5T OF OUR PLANET, THE EARTH. ROCKS ARE
made up of minerals, and minerals themselves are made up of elements. Unlike animals and plants, rocks are not alive. But that does not mean they always stay the same - in fact, they are changing all the time. Rocks can dissolve, melt, fali apart and even change into other rocks.
What are elements?
Elements are simple chemical substances such as gold and oxygen.They are the building blocks of most other substances. In fact, most things, including rocks, minerals, animals, plants, people, water and air are made up of combinations of elements.
Is the whole of the Earth made of rocks?
Yes - you could say the Earth is one gigantic rock! But the kind of rock we are used to seeing is only on the outside, or crust. Where this crust forms the Earth's continents, the most common rock is gránité.
What is the difference between a rock and a mineral?
The main difference is that a mineral is 'homogeneous' - it is the same all the way through. If you look at a lump of salt under a microscope, every part of it has the same structure. But rock is not homogeneous, it is a mixture. For example, gránité, a rock, is made up of three minerals, mica, feldspar and quartz.
How can animals and plants be rocks and minerals?
Substances like chalk, coal and oil were förmed millions of years ago when plants or tiny sea creatures got squashed under layers of mud and water and eventually turnéd into stone. Somé scientists say that things which were once alive are not true minerals. But you will find them in most books on rocks and minerals - including this one!