Bill nye rock cycle

Bill Nye the Science Guy brought to you

by rocks did you ever stop to think that

the whole world is covered with rocks

and every rock used to be different when

you're looking at a rock you're looking

at history careful see all the rocks in

the world used to be melted rocks what

we call molten rocks molten like this

molten rock in here do you see the

bubble on top it's from the heat it's

just like the rocks that come out of

volcanoes rocks like this rocks like

this rocks like these see these pits

they were formed by bubbles and liquid

rock that came out of a volcano now

sometimes the rock from volcanoes will

come up onto the Earth's surface now in

these rocks get on the Earth's surface

they push other rocks down it pushes

down on the layers below push the old

rocks down push them down and they'll

squeeze together and swirl around when

they blend together they form a new type

of rock like the minerals that are

swirled together in this piece of marble

anyway wind and rain moving over the

Earth's surface break rock down into

sand sometimes enough water will flow

through the dust and sand mix them

together push it around it'll dry out

again and turn back into rock like these

good they are my safety glasses huh now

this process where rocks are formed

broken down and reforming as they come

out of the molten earth and turn back

into dust into rocks again it's been

going on since the world was formed

billions billions of years billions of

years ago rocks Rock rocks rocks rocks

are formed in different ways all the

material in the sandstone once belonged

to other rocks that rocks

scientists like to think of three types

of rock now the first type you might

call igneous rock igneous rock now

igneous comes from the word for fire

you know you ignite the candle and you

have igneous rocks you know igneous

ignite that's from the word for fire so

see how the candle wax drips down the

outside of the candle

well igneous rocks are often formed when

hot lava drips down the outsides of

volcanoes and it cools to form rocks

like this granite they the next type of

rock call sedimentary rock now sediment

that's silk mud goop and rivers so if

you have a river and it's washing sand

mud or silt sediment downstream

well eventually the river may dry up or

drain away leaving the sediment the sand

silt or mud now this sand would be heavy

it crushes down on itself like this

squeezing itself together till

eventually after water is completely

drained away after a few thousand years

you end up with a rock like this one see

the layers sedimentary rock often has

layers in it because that's the way sand

washes downstream in a river now the

last type of rock is sort of a

combination of the other two we call it

metamorphic rock metamorphic means it's

changed its metamorphosized so if we

look at this this is rock that was once

in but it's been smushed together by

huge pressures under very high heat

pressure and heat smashing the rock till

it's just crushed flat like this

see heat and pressure formed another