A guide to the energy of the Earth - Joshua M. Sneideman
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0:07 - 0:10Energy is all around us,
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0:10 - 0:14a physical quantity that follows
precise natural laws. -
0:14 - 0:16Our universe has a finite amount of it;
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0:17 - 0:19it's neither created nor destroyed
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0:19 - 0:20but can take different forms,
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0:20 - 0:23such as kinetic or potential energy,
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0:23 - 0:26with different properties
and formulas to remember. -
0:26 - 0:27For instance,
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0:27 - 0:30an LED desk lamp's 6 Watt bulb
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0:30 - 0:33transfers 6 Joules
of light energy per second. -
0:34 - 0:36But let's jump back up into space
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0:36 - 0:39to look at our planet,
its systems, and their energy flow. -
0:40 - 0:42Earth's physical systems include
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0:42 - 0:44the atmosphere, hydrosphere,
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0:44 - 0:47lithosphere, and biosphere.
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0:47 - 0:50Energy moves in and out of these systems,
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0:50 - 0:52and during any energy
transfer between them, -
0:52 - 0:55some is lost to the surroundings,
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0:55 - 0:57as heat, light, sound,
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0:57 - 0:59vibration, or movement.
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1:00 - 1:03Our planet's energy comes from
internal and external sources. -
1:03 - 1:07Geothermal energy
from radioactive isotopes -
1:07 - 1:10and rotational energy
from the spinning of the Earth -
1:10 - 1:12are internal sources of energy,
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1:12 - 1:15while the Sun
is the major external source, -
1:15 - 1:18driving certain systems,
like our weather and climate. -
1:18 - 1:22Sunlight warms the surface and atmosphere
in varying amounts, -
1:22 - 1:24and this causes convection,
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1:24 - 1:26producing winds
and influencing ocean currents. -
1:27 - 1:32Infrared radiation, radiating out
from the warmed surface of the Earth, -
1:32 - 1:36gets trapped by greenhouse gases
and further affects the energy flow. -
1:37 - 1:40The Sun is also the major source
of energy for organisms. -
1:41 - 1:43Plants, algae, and cyanobacteria
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1:43 - 1:46use sunlight to produce organic matter
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1:46 - 1:48from carbon dioxide and water,
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1:48 - 1:51powering the biosphere's food chains.
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1:51 - 1:54We release this food energy
using chemical reactions, -
1:54 - 1:57like combustion and respiration.
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1:57 - 2:00At each level in a food chain,
some energy is stored -
2:00 - 2:02in newly made chemical structures,
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2:02 - 2:05but most is lost to the surroundings,
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2:05 - 2:07as heat, like your body heat,
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2:07 - 2:09released by your digestion of food.
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2:09 - 2:12Now, as plants are eaten
by primary consumers, -
2:12 - 2:17only about 10% of their total energy
is passed on to the next level. -
2:17 - 2:21Since energy can only flow
in one direction in a food chain, -
2:21 - 2:24from producers on to consumers
and decomposers, -
2:24 - 2:27an organism that eats lower
on the food chain, -
2:27 - 2:29is more efficient than one higher up.
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2:30 - 2:32So eating producers
is the most efficient level -
2:32 - 2:35at which an animal can get its energy,
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2:35 - 2:39but without continual input of energy
to those producers, -
2:39 - 2:40mostly from sunlight,
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2:40 - 2:43life on Earth as we know it
would cease to exist. -
2:43 - 2:47We humans, of course, spend our energy
doing a lot of things besides eating. -
2:47 - 2:52We travel, we build, we power
all sorts of technology. -
2:52 - 2:53To do all this,
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2:53 - 2:55we use sources like fossil fuels:
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2:55 - 2:58coal, oil, and natural gas,
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2:58 - 3:00which contain energy
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3:00 - 3:02that plants captured
from sunlight long ago -
3:02 - 3:05and stored in the form of carbon.
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3:05 - 3:07When we burn fossil fuels in power plants,
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3:07 - 3:09we release this stored energy
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3:09 - 3:11to generate electricity.
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3:12 - 3:13To generate electricity,
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3:13 - 3:17heat from burning fossil fuels
is used to power turbines -
3:17 - 3:19that rotate magnets,
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3:19 - 3:21which, in turn, create
magnetic field changes -
3:21 - 3:24relative to a coil of wire,
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3:24 - 3:28causing electrons to be
induced to flow in the wire. -
3:28 - 3:31Modern civilization depends on our ability
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3:31 - 3:34to keep powering that flow of electrons.
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3:34 - 3:38Fortunately, we aren't limited
to burning non-renewable fossil fuels -
3:38 - 3:40to generate electricity.
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3:40 - 3:42Electrons can also be induced to flow
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3:42 - 3:45by direct interaction
with light particles, -
3:45 - 3:47which is how a solar cell operates.
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3:48 - 3:49Other renewable energy sources,
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3:49 - 3:51such as wind, water,
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3:51 - 3:54geothermal, and biofuels
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3:54 - 3:56can also be used to generate electricity.
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3:57 - 4:00Global demand for energy is increasing,
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4:00 - 4:02but the planet
has limited energy resources -
4:02 - 4:05to access through a complex
energy infrastructure. -
4:05 - 4:07As populations rise,
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4:07 - 4:10alongside rates of industrialization
and development, -
4:10 - 4:13our energy decisions grow
more and more important. -
4:13 - 4:17Access to energy
impacts health, education, -
4:17 - 4:20political power, and socioeconomic status.
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4:20 - 4:22If we improve our energy efficiency,
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4:22 - 4:25we can use our natural resources
more responsibly -
4:25 - 4:28and improve quality of life for everyone.
- Title:
- A guide to the energy of the Earth - Joshua M. Sneideman
- Description:
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View full lesson: http://ed.ted.com/lessons/a-guide-to-the-energy-of-the-earth-joshua-m-sneideman
Energy is neither created nor destroyed — and yet the global demand for it continues to increase. But where does energy come from, and where does it go? Joshua M. Sneideman examines the many ways in which energy cycles through our planet, from the sun to our food chain to electricity and beyond.
Lesson by Joshua M. Sneideman, animation by Marc Christoforidis.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 04:44
Krystian Aparta edited English subtitles for A guide to the energy of the Earth - Joshua M. Sneideman | ||
Krystian Aparta commented on English subtitles for A guide to the energy of the Earth - Joshua M. Sneideman | ||
Caroline Cristal edited English subtitles for A guide to the energy of the Earth - Joshua M. Sneideman | ||
Caroline Cristal edited English subtitles for A guide to the energy of the Earth - Joshua M. Sneideman | ||
Caroline Cristal approved English subtitles for A guide to the energy of the Earth - Joshua M. Sneideman | ||
Caroline Cristal accepted English subtitles for A guide to the energy of the Earth - Joshua M. Sneideman | ||
Caroline Cristal edited English subtitles for A guide to the energy of the Earth - Joshua M. Sneideman | ||
Caroline Cristal edited English subtitles for A guide to the energy of the Earth - Joshua M. Sneideman |
Krystian Aparta
The English transcript was updated on 2/13/2015.