Presentation on theme: "Rocks and Fossil Fuels. Think about rocks. What do rocks look like?"— Presentation transcript:
Rocks and Fossil Fuels
Think about rocks. What do rocks look like?
Is this what you thought of?
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 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. 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!