rocks and fossil fuels. think about rocks. what do rocks look like?

Rocks and Fossil Fuels

Think about rocks.

What do rocks look like?

Is this what you thought of?

Or this?

OR THIS????

OR…. THIS!!!!

Rocks can be small or big!

We are going to learn 3 different rocks and how they are made!

Igneous Rock

Comes from melted rock like magma

There are lots of different igneous rocks because sometimes minerals

get mixed in before it hardens.

Also, igneous rocks look different depending on how fast they cool.

If a rock cools quickly, there is no time for large mineral grains to

form.

If it cools slowly… what do you think?

Examples of igneous rock:

granite

This rock must have cooled slowly because of all of the mineral grains in it

Hint: Granite sounds like GRAINS!

This rock is obsidian, it is smooth.

Did this rock cool fast or slow?

FAST!!

There wasn’t time for large minerals to form

What about basalt? It has tiny, tiny mineral grains but it is mostly

smooth.

Yes, this rock must have cooled quickly

The second type of rock is called:

Sedimentary Rock

Sedimentary rock forms from layers of sediment.

Sediment is tiny bits of weathered and eroded rock.

Sediment can even be once living plants or animals!

Sediment is rocks and other things that have SETTLED together,

like at the bottom of a lake or river.

Settled = Sediment

This is weathered rock that has eroded and settled on the ground.

THIS IS SEDIMENT

Sedimentary rock is made of layers,CAN YOU SEE THE LAYERS??

For thousands, even millions of years, little pieces of our earth have been eroded--

broken down and worn awayby wind and water. These little bits of our earth are

washed downstream where they settle to the bottom of the rivers, lakes, and oceans.

Layer after layer of eroded earth is deposited on top of

each. These layers are pressed down more and

more through time, until the bottom layers slowly turn

into rock.

Each layer can be a different mixture of sediment.

Shale is sedimentary

Metamorphic Rock

Rock that has been changed by heat and pressure

SQUEEZING!