Igneous : a rock formed from magma either inside the Earth or on the surface. Impermeable : cannot easily let water in. Loam soil: a soil which is a fairly even mixture of sand, clay and silt. Magma : liquid rock that is very hot. Metamorphic : a rock formed when existing rock is changed through heat and pressure. Organic material: dead or decaying matter found at the top of soil. This lies just on top of the topsoil. Parent material: the broken rock from which a soil is formed. It is found at the bottom of a soil profile.
Peat : a dark soil that is mainly made from partly decayed plant material. Permeable : can easily let water in Porous : something that has gaps in it that water can get in to. Rock : a solid formed of the particles of one or more minerals. Rock cycle: the movement and recycling of rocks by nature. Rocks change from one type to another during this process.
Sandy soil: soil that has a high proportion of sand. Sedimentary rock : rock formed when layers of mineral particles are squashed together Silt : fine rock particles that are not as fine as clay, but not as coarse as sand.
Soil profile: the various layers if soil from organic matter on top to the bedrock at the bottom. Topsoil : the first proper layer or horizon of soil which is found when you dig into soil.
Need help? How to videos Why join? Rocks and soil. What are rocks and soil? Most of our planet is made of rocks which are made of minerals; minerals are made of elements. Rocks and minerals are not the same thing. The oldest rocks ever to be found were formed about 4 billion years ago — only two pieces of rock this old have ever been found. Soil is vital to life on Earth because plants can't grow without the water and nutrients it contains, and animals can't survive without plants.
All our food needs to grow on this. It is also not renewable, so we need to look after it. Soil can be damaged by erosion or pollution. Soil can be looked after by protecting it against these two things.
It takes over years for just 2cm of topsoil to form. There are approximately 10, different types of soil found in Europe. The number of micro-organisms found in a cup of soil is greater than the number of people on Earth. Some of our soil has in it the dusty remains of stars that have been pulled to Earth by gravity or another force. Start your child on a tailored learning programme Weekly resources sent direct to your inbox Keep your child's learning on track.
Trial it for FREE today. Meteorites are rocks that have landed on Earth from space — they were not formed on the Earth. This means, for example, that scientists have been able to study rocks from Mars without ever going there. When meteors land on Earth they usually leave a big hole, or crater, where they hit the ground. The chalks that you draw and write with are made from limestone. The largest meteorite ever discovered weighed 66 tonnes. It was named Hoba after the farm in Africa that it was found on.
Pumice rock is so full of air that it floats. If lightning hits a beach it can make the sand reach such a high temperature that it melts to form fulgurite, which is a glassy rock. Obsidian is an igneous rock that is sometimes referred to as natural glass. It is so sharp that it is used by surgeons in surgical scalpels. It is also often used, when polished, in jewellery. Most gemstones that are used in jewellery are minerals rather than rocks.
There are lots of variations of these soil types Peat is a type of soil that forms in waterlogged areas from partly decayed plants. Peat helps scientists to find out about living things from a long time ago as it preserves plants and animals very well. It takes a very long time to form about 1mm per year and so it a precious resource. Look through the gallery below and see if you can spot the following: Sandstone sedimentary rock Granite igneous rock Marble metamorphic rock Sedimentary rock Formation of metamorphic rock The rock cycle A church made from limestone Plates made from clay Pumice Rock collection Soil profile Clay soil Sandy soil Loam soil Peat Earthworm Mole.
Words to know: Bedrock : the solid rock that is found once you have dug through all the layers of soil. Watch BBC Bitesize animations about soil and rocks , then take quizzes to show what you've learned Can you complete this rock cycle?
Can you order the various soil layers in a soil profile? Can you complete an interactive rock cycle? Like a biography, each profile tells a story about the life of a soil. Most soils have three major horizons A, B, C and some have an organic horizon O.
The horizons are:. O — humus or organic Mostly organic matter such as decomposing leaves. The O horizon is thin in some soils, thick in others, and not present at all in others. A - topsoil Mostly minerals from parent material with organic matter incorporated. A good material for plants and other organisms to live.
E — eluviated Leached of clay, minerals, and organic matter, leaving a concentration of sand and silt particles of quartz or other resistant materials — missing in some soils but often found in older soils and forest soils. B — subsoil Rich in minerals that leached moved down from the A or E horizons and accumulated here.
R — bedrock A mass of rock such as granite, basalt, quartzite, limestone or sandstone that forms the parent material for some soils — if the bedrock is close enough to the surface to weather.
This is not soil and is located under the C horizon. Click here to learn more about SSSA…. Skip to main content. What is Soil? Soil, as formally defined in the Soil Science Society of America Glossary of Soil Science Terms, is: The unconsolidated mineral or organic material on the immediate surface of the earth that serves as a natural medium for the growth of land plants.
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