Rocks Here, There, Everywhere Mrs. Tweedie April 2008

Rocks You can find rocks just about anywhere. One rock can be very different from another.

Sedimentary Rocks Have you ever seen a rock with layers? Some of these rocks were formed under water.

They are made up of pieces of other rocks and things like sand, clay, and mud that settled in layers under water. After a long time, the layers piled up and stuck together. Sedimentary Rocks

Sometimes, plants, bones, or sea shells got caught in the layers Sometimes, plants, bones, or sea shells got caught in the layers. They formed fossils. Some fossils are the prints of plants and animals that lived long ago. Sedimentary Rocks

Other fossils are actual parts of plants or animals that have been mineralized. Sedimentary Rocks

Do you know what a pebble is Do you know what a pebble is? If you look closely, you can see pebbles in some rocks that formed under water. Sedimentary Rocks Conglomerate

Because these rocks are formed of sediment, or bits and pieces of matter that have settled to the bottom of water, scientists call them sedimentary rocks. Sedimentary Rocks Sandstone

Sedimentary Rocks Summary For thousands, even millions of years, little pieces of our earth have been eroded--broken down and worn away by wind and water. These little bits of our earth are washed downstream where they settle to the bottom of the rivers, lakes, and oceans.

Sedimentary Rocks Summary Layer after layer of eroded earth is deposited on top of each previous layer. These layers are pressed down more and more through time, until the bottom layers slowly turn into rock.

Igneous Rock Some rocks were formed inside the earth. Deep inside the earth, it is very hot. In fact, it is so hot that rocks melt!

Igneous Rock Melted underground rock is called magma. Rocks formed from magma are called igneous.

Igneous Rock Sometimes the magma erupts through the surface of the earth. Rocks, flames, and steam spout toward the sky.

Igneous Rock When this happens, the magma gets a new name. It is called lava. As the lava piles up and hardens, it forms a volcano.

Igneous Rock Obsidian Rock Rocks from volcanoes don’t always look the same. Some look like glass. They are smooth. This is because they cooled fast.

Igneous Rock Pumice Other rocks from volcanoes cooled slowly. Gas bubbled out, causing small holes to form. Their surface is often rough.

Igneous Rock Volcanoes often erupt more than once. As soon as the lava starts to harden, more lava lands on top of it!

Rocks formed this way have bands, or streaks, in them. Igneous Rock Granite Rocks formed this way have bands, or streaks, in them.

Igneous Rock Basalt Sometimes the magma cools very slowly underground. Rocks formed in this way are very hard and heavy. You can see pieces of minerals in them.

Igneous Rock Summary Igneous rocks are called fire rocks and are formed either underground or above ground. Underground, they are formed when the melted rock, called magma, deep within the earth becomes trapped in small pockets. As these pockets of magma cool slowly underground, the magma becomes igneous rocks.

Igneous Rock Summary Igneous rocks are also formed when volcanoes erupt, causing the magma to rise above the earth's surface. When magma appears above the earth, it is called lava. Igneous rocks are formed as the lava cools above ground.

Metamorphic Rock Rocks don’t always stay where they are formed. Overtime, earthquakes move them around.

Metamorphic Rock As rocks are moved, they can change. They become twisted. They can even break up.

Metamorphic Rock Heat also changes rocks. There is heat just under the surface of the earth.

Metamorphic Rock It is not hot enough to turn rocks into liquid, but it is hot enough to change them.

Metamorphic Rock Gneiss Slate Schist marble Rocks that have been changed by underground pressure or heat are called metamorphic.

Metamorphic Rock Summary Metamorphic rocks are rocks that have "morphed" into another kind of rock. These rocks were once igneous or sedimentary rocks. How do sedimentary and igneous rocks change?

Metamorphic Rock Summary The rocks are under tons and tons of pressure, which fosters heat build up, and this causes them to change. If you examine metamorphic rock samples closely, you'll discover how flattened some of the grains in the rock are.

Rocks Here, There, Everywhere Rocks will give us clues about how and where they were formed-if we take time to look at them closely.