Rocks
Rocks, Soils and Fossils KS1/KS2/KS3
There are three different types of rocks on earth. Metamorphic, Sedimentary and
Igneous. Examples of rocks to hold. Fossils are found in sedimentary rocks. Fossils
provide evidence that different life existed in the past. Rocks and Soils are used for
many purposes. Houses, roads and factories are built with materials from rocks. Glass
is produced. Soils types to hold. Metal extraction. Panning for fools gold
Fossils
The only direct way we have of learning about dinosaurs is by studying fossils.
Fossils are the remains of ancient animals and plants, the traces or impressions of
living things from past geologic ages, or the traces of their activities. Fossils have
been found on every continent on Earth, maybe even near where you live.
The word fossil comes from the Latin word fossilis, which means "dug up." Most
fossils are excavated from sedimentary rock layers. Sedimentary rock is rock that has
formed from sediment, like sand, mud, small pieces of rocks. Over long periods of
time, these small pieces of debris are compressed (squeezed) as they are buried under
more and more layers of sediment that piles up on top of it. Eventually, they are
compressed into sedimentary rock. The layers that are farther down in the Earth are
older than the top layers.
The fossil of a bone doesn’t have any bone in it! A fossilized object has the same
shape as the original object, but is chemically more like a rock.
Palaeontology is the branch of biology that studies the forms of life that existed in
former geologic periods, chiefly by studying fossils.
What Do Fossils Look Like?
Fossils have the same shape that the original item had, but their colour, density, and
texture vary widely. A fossil's colour depends on what minerals formed it. Fossils are
usually heavier than the original item since they are formed entirely of minerals
(they're essentially stone that has replaced the original structure). Most fossils are
made of ordinary rock material, but some are more exotic, including one fossilized
dinosaur bone, a Kakuru tibia, which is an opal!
Soil
Soil, like air and water, is one of the world's most important natural resources.
Because it lies beneath our feet and is often hidden by buildings and roads we
may not often think about how much it affects our lives and how much we
depend on it.
Most of our food depends on soil - it is where we find the plants and many of the
animals which make up our food, and it is home for billions of organisms. Soil
also gives support for many of our buildings and structures.
Soils form very slowly, maybe as little as 1 cm of thickness in 500 years, so we
can't just replace them in our own lifetime. Many of our soils are becoming
damaged and are at risk.
It is important that we understand our soil and make sure it is there for future
generations. Soil-Net will help you learn more about our precious soil.
The character and make-up of the soil play an important part in the behaviour of
soils and what they are used for. Two of the most important properties of soils
are their texture and structure.
Soil texture is an expression used to describe the physical components of the soil.
Words such as clay, sand and loam have been used since ancient times to
distinguish soils with different properties. Four standard words are now used in
various combinations - sand, clay, loam and silt to describe the proportions of
sand-, silt- and clay-sized particles in a sample. This must not be confused with
soil structure which describes the way these individual particles are assembled
and bound into groups (aggregates).
Soil texture can give a guide to:
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Soil water - its retention and release to plants;
Soil structure - its development and stability;
Nutrient retention and availability;
Activity and retention of residual soil-acting herbicides;
Erodibility by wind and water;
Stickiness and ease of cultivation;
Drainage characteristics and suitability for artificial drainage;
Cropping suitability;
Soil temperature changes.