WEBVTT

00:00:00.190 --> 00:00:03.900
- [Instructor] Today, let's
talk about energy resources.

00:00:03.900 --> 00:00:06.140
You've probably already
done something today

00:00:06.140 --> 00:00:08.160
that used energy resources,

00:00:08.160 --> 00:00:10.500
even beginning from
the moment you woke up.

00:00:10.500 --> 00:00:12.330
For me, the beginning of my day

00:00:12.330 --> 00:00:14.600
always starts with making tea.

00:00:14.600 --> 00:00:17.430
I use energy in every
step of this process.

00:00:17.430 --> 00:00:20.010
My car uses oil when I
drive to the grocery store

00:00:20.010 --> 00:00:21.150
to get the tea,

00:00:21.150 --> 00:00:24.410
my stove uses natural gas
when I boil the water,

00:00:24.410 --> 00:00:27.410
and my water heater uses
coal-sourced electricity

00:00:27.410 --> 00:00:30.020
when I wash my mug in
hot water afterwards.

00:00:30.020 --> 00:00:33.060
We use energy constantly
in our daily lives.

00:00:33.060 --> 00:00:35.120
Since the first law of thermodynamics

00:00:35.120 --> 00:00:38.570
states that energy cannot
be created nor destroyed,

00:00:38.570 --> 00:00:42.560
where does it all come from
and will we have enough?

00:00:42.560 --> 00:00:44.750
When we talk about energy resources,

00:00:44.750 --> 00:00:46.960
we could split it up into two groups:

00:00:46.960 --> 00:00:50.930
renewable energy and nonrenewable energy.

00:00:50.930 --> 00:00:53.440
I can always remember what
renewable resources are

00:00:53.440 --> 00:00:55.940
because the prefix re means again

00:00:55.940 --> 00:00:59.240
and the root new refers the
origin of the energy source,

00:00:59.240 --> 00:01:01.090
so renewable energy sources

00:01:01.090 --> 00:01:03.480
are the sources that we
can use again and again

00:01:03.480 --> 00:01:06.640
and are quickly restored
by natural processes.

00:01:06.640 --> 00:01:10.270
Renewable fuel sources
include sunlight, wind,

00:01:10.270 --> 00:01:13.150
moving water, biomass
from fast-growing plants,

00:01:13.150 --> 00:01:15.880
and geothermal heat from the earth.

00:01:15.880 --> 00:01:19.220
The lifespan of renewable
resources looks like a circle.

00:01:19.220 --> 00:01:21.460
We can use them and then
we can use them again

00:01:21.460 --> 00:01:23.320
without worrying about them running out.

00:01:23.320 --> 00:01:25.900
Nonrenewable energy
sources on the other hand,

00:01:25.900 --> 00:01:28.260
are sources that exist in a fixed amount

00:01:28.260 --> 00:01:30.120
and cannot be easily replaced.

00:01:30.120 --> 00:01:33.430
These energy sources must
be extracted from the earth,

00:01:33.430 --> 00:01:38.140
and they include things like
nuclear fuel and fossil fuels,

00:01:38.140 --> 00:01:42.240
which are things like
coal, oil, and natural gas.

00:01:42.240 --> 00:01:45.130
Fossil fuels were formed
in the geologic past

00:01:45.130 --> 00:01:47.510
from the remains of ancient organisms.

00:01:47.510 --> 00:01:50.580
Plants and animals that
died millions of years ago

00:01:50.580 --> 00:01:54.410
became buried in the soil,
partially decomposed,

00:01:54.410 --> 00:01:57.153
and were exposed to a
lot of heat and pressure.

00:01:58.380 --> 00:02:01.030
This heat and pressure
chemically rearranged

00:02:01.030 --> 00:02:03.150
the energy contained within their bodies

00:02:03.150 --> 00:02:05.670
into the fossil fuels we use today.

00:02:05.670 --> 00:02:09.620
Because they take so long to
form, we have a finite amount

00:02:09.620 --> 00:02:12.710
of nonrenewable resources
in the earth right now.

00:02:12.710 --> 00:02:16.010
The lifespan for fossil
fuels is a broken loop,

00:02:16.010 --> 00:02:17.880
a one-way ticket.

00:02:17.880 --> 00:02:20.380
First, the fossil fuel is found,

00:02:20.380 --> 00:02:22.980
then it has to be extracted.

00:02:22.980 --> 00:02:24.390
Extracting fossil fuels

00:02:24.390 --> 00:02:26.650
can involve destructive mining processes

00:02:26.650 --> 00:02:29.190
that can pollute surrounding habitats.

00:02:29.190 --> 00:02:32.760
It then has to be transported
to wherever it will be used.

00:02:32.760 --> 00:02:35.940
And using fossil fuels means burning them,

00:02:35.940 --> 00:02:37.720
which releases greenhouse gases

00:02:37.720 --> 00:02:40.270
and other pollutants into the atmosphere.

00:02:40.270 --> 00:02:41.880
Also, it can take energy

00:02:41.880 --> 00:02:44.310
to refine and process
some types of fossil fuel

00:02:44.310 --> 00:02:45.910
so that they're more helpful to us,

00:02:45.910 --> 00:02:48.410
like turning crude oil into petroleum gas,

00:02:48.410 --> 00:02:50.070
diesel, and jet fuel,

00:02:50.070 --> 00:02:53.080
and burning the fossil
fuels transforms that energy

00:02:53.080 --> 00:02:57.343
into a less organized form
of energy like heat and ash.