he knows a lot about the science stuff
professor dave explains
this is earth a rocky planet covered
with liquid water orbiting within the
habitable zone of a very typical star
from afar it may not look like much but
if you get close enough it becomes quite
clear that there is a lot to study on
this little blue world
some choose to study botany to learn
about the wide variety of plant life
some study zoology and learn about all
the animals walking on the land flying
in the air and swimming in the ocean
but some choose to study the earth
itself
what is the precise composition of the
earth what is its history the people who
answer these questions are geologists
now when most people think of a
geologist they tend to imagine someone
examining a bunch of rocks and of course
geologists do indeed study rocks but
geology is also much more than this
to understand why earthquakes occur or
how volcanoes form one must do more than
simply look at rocks
at its core geology is a
multi-disciplinary science that combines
chemistry physics and mathematics to
investigate an enormous variety of
processes that occur on and in the earth
as we will come to understand in this
series geology encompasses every aspect
of earth's structure from the molten
iron core to the beautiful minerals we
find on its surface
much of what geologists study transpired
over incredibly long time scales
originating anywhere from thousands to
billions of years in the past
geologic processes have shaped the
entirety of earth's surface
for example the appalachian mountains of
eastern north america contain limestones
which are composed of the shells of
marine animals that lived there in a
shallow ocean more than 400 million
years ago
then 300 million years ago those rock
beds were thrust upwards as earth's
tectonic plates began to converge along
the eastern u.s coast
later during glacial periods between 2
million and 12 000 years ago mile thick
ice sheets scraped off the tops of these
mountains like huge bulldozers as they
moved southward then deposited hundreds
of feet of sand and gravel in stream
valleys as they retreated northward and
melted
how is it that we can know these things
exactly and furthermore why even bother
studying geology if all these phenomena
occur on a much longer time scale than
humans can observe during their
lifetimes the simple answer is that the
processes that shaped our planet
billions of years ago still occur today
and can be easily observed and measured
next time you visit the beach pay close
attention to the patterns of the sand
and observe them as they form from wind
and water currents
these patterns are exactly what we find
in many ancient sandstones therefore it
is reasonable to assume they were
created by the same processes just at
different points in time
this is the essence of geology observing
beach sand form ripples and dunes may
not be the most exciting activity to
most so you might be wondering who would
be interested in geology the first
recorded dabbling in geology was by
aristotle and the ancient greeks these
ancient philosophers wanted to
understand natural phenomena especially
those impactful to human life like
earthquakes volcanoes and tidal waves
aristotle thought earthquakes were
caused by opposing winds within the
cavernous earth while democritus thought
the cause was water forcing its way into
the earth as it rains
obviously these are both incorrect and
we now know earthquakes to be caused by
rocks cracking under the enormous stress
created by plate tectonics but the
desire to understand is ancient
geology has come a long way since the
time of aristotle and has many
applications toward improving and
protecting human life for example
volcanologists or geologists who study
volcanoes closely monitor active ones
and create early warning systems to
evacuate towns before any volcanic
eruptions
furthermore earth contains minerals
metals and sources of energy that we
have used to build and power the
technology and infrastructure
responsible for raising our collective
standard of living over the past few
hundred years
in fact many geologists work in the
resource industry finding new places or
developing new ways to extract minerals
and energy
others assess hazards to human life like
the volcanic eruptions we mentioned but
also slope failures massive floods and
structural damage from earthquakes
biologists interested in the evolution
of life on earth work closely with
geologists in looking at the rock record
to find the fossils and footprints of
organisms that are now long extinct
climate scientists interested in
understanding our impact on the
environment measure among other things
greenhouse gases trapped inside tiny
bubbles from eight hundred thousand
year-old ice cores
the impact doesn't even stop at our own
planet the understanding of earth
provided by geologists acts as the
framework that planetary scientists use
to study outflow channels on mars
crater topography on the moon and unique
features of exoplanets that are
continually being discovered
so as you can see geology is not just
about looking at rocks it is as rich and
multifaceted as any other scientific
discipline as we mentioned geology
utilizes concepts in chemistry physics
and mathematics and an understanding of
basic concepts from these fields will be
assumed as we move through this geology
series
when we talk about the structure of
various minerals we won't be reviewing
chemistry concepts regarding atomic and
molecular structure and when we talk
about large-scale geological events we
won't be reviewing physics terminology
regarding forces and energy nor the
basic algebra that is sometimes required
to discuss these phenomena
quantitatively so if you need to brush
up on any of these subjects my playlists
in general chemistry classical physics
and mathematics will be of great use but
otherwise when we encounter a topic that
assumes such prior knowledge i will
always link to the relevant tutorial
using cards that appear in the upper
right corner of the screen in case you
need a brief refresher but whatever your
current level of knowledge if you're
invigorated by the thought of learning
all about this beautiful planet we all
live on let's start learning geology
thanks for watching subscribe to my
channel for more tutorials support me on
patreon so i can keep making content and
as always feel free to email me
professordaveexplains gmail.com
[Music]
you