All of the energy in the universe is... - George Zaidan and Charles Morton
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0:08 - 0:10Energy is not easy to define.
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0:10 - 0:12Things have energy,
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0:12 - 0:13but you can't hold
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0:13 - 0:15a bushel of energy in your hands.
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0:15 - 0:16You can see what it does,
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0:16 - 0:19but you can't see it directly.
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0:19 - 0:21There are different types of energy,
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0:21 - 0:22but the differences between them
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0:22 - 0:26are manifested only in how they make stuff behave.
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0:26 - 0:27We do know that the total amount
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0:27 - 0:29of all the different types of energy in the universe
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0:29 - 0:31is always the same.
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0:31 - 0:34And, for chemists, two important types of energy
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0:34 - 0:35are chemical potential energy
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0:35 - 0:37and kinetic energy.
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0:37 - 0:40Potential energy is energy waiting to happen.
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0:40 - 0:42Think of a stretched rubber band.
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0:42 - 0:43If you cut it,
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0:43 - 0:44all that potential energy
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0:44 - 0:47gets converted to kinetic energy,
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0:47 - 0:50which is registered by you as pain.
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0:50 - 0:51Like a stretched rubber band,
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0:51 - 0:53chemical bonds also store energy,
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0:53 - 0:54and when those bonds are broken,
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0:54 - 0:56that potential energy gets converted
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0:56 - 0:57to other types of energy,
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0:57 - 0:58like heat or light,
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0:58 - 1:01or gets used to make different bonds.
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1:01 - 1:03Kinetic energy is the energy of motion,
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1:03 - 1:06and molecules are always moving.
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1:06 - 1:08They're not necessarily going somewhere,
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1:08 - 1:09though they could be,
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1:09 - 1:10but they are vibrating,
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1:10 - 1:11stretching,
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1:11 - 1:11bending,
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1:11 - 1:12and/or spinning.
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1:12 - 1:13Take methane,
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1:13 - 1:14which is four hydrogens
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1:14 - 1:16attached to a central carbon,
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1:16 - 1:17as an example.
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1:17 - 1:18Drawn on paper,
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1:18 - 1:20it's just a still tetrahedron.
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1:20 - 1:22But in real life, it's a jiggling mess.
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1:22 - 1:24The kinetic energy of molecules
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1:24 - 1:26is exactly the same type of energy
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1:26 - 1:27as the energy you have
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1:27 - 1:28when you're moving around,
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1:28 - 1:30except that you can be still
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1:30 - 1:32and molecules can't.
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1:32 - 1:33If you suck the kinetic energy
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1:33 - 1:35out of a group of molecules,
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1:35 - 1:36they'll move less,
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1:36 - 1:37but they'll never fully stop.
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1:37 - 1:39Now, in any group of molecules,
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1:39 - 1:42some will have more kinetic energy than others.
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1:42 - 1:43And if we calculate
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1:43 - 1:45the average kinetic energy of the group,
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1:45 - 1:47we'd have a number mathematically related to
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1:47 - 1:49temperature.
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1:49 - 1:50So, the more kinetic energy
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1:50 - 1:51a group of molecules has,
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1:51 - 1:53the higher its temperature.
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1:53 - 1:55And that means that on a hot day,
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1:55 - 1:56the molecules in the air around you
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1:56 - 1:58are spinning, stretching, bending,
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1:58 - 2:00and generally shooting around much faster
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2:00 - 2:02than on a cold day.
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2:02 - 2:04Now, hot and cold, by the way,
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2:04 - 2:06are relative terms.
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2:06 - 2:07They're always used to compare
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2:07 - 2:09one thing to something else.
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2:09 - 2:10So, on that hot summer day,
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2:10 - 2:12the air molecules have more kinetic energy
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2:12 - 2:15than the molecules in your skin.
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2:15 - 2:17So, when those air molecules crash into you,
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2:17 - 2:19they transfer some of their energy
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2:19 - 2:20to the molecules in your skin,
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2:20 - 2:23and you feel that as heat.
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2:23 - 2:24On a cold day,
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2:24 - 2:26the air molecules have less kinetic energy
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2:26 - 2:27than the molecules in your skin,
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2:27 - 2:29so when you crash into those air molecules,
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2:29 - 2:31you actually transfer
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2:31 - 2:33some of your kinetic energy to them,
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2:33 - 2:36and you feel that as cold.
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2:36 - 2:39You can trace the path of energy around you.
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2:39 - 2:40Try it at your next cookout.
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2:40 - 2:41You burn charcoal
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2:41 - 2:43and the release of that chemical potential energy
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2:43 - 2:46shows up as extreme heat and light.
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2:46 - 2:47The heat then makes the molecules
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2:47 - 2:50of your burgers, your hot dogs, or your vegetables
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2:50 - 2:52vibrate until their own bonds break
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2:52 - 2:55and new chemical structures are formed.
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2:55 - 2:57Too much heat and you have a charred mess;
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2:57 - 2:58just enough and you have dinner.
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2:58 - 2:59Once in your body,
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2:59 - 3:01the food molecules in your delicious,
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3:01 - 3:02or charred,
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3:02 - 3:04dinner get broken down,
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3:04 - 3:05and the energy released
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3:05 - 3:07is used to either keep you alive right now
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3:07 - 3:10or it's stored for later in different molecules.
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3:10 - 3:12As night falls,
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3:12 - 3:13the hot summer air cools
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3:13 - 3:16and the flow of energy into you slows.
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3:16 - 3:19Then, as the air reaches your skin temperature,
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3:19 - 3:20for the briefest of moments,
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3:20 - 3:21the flow stops.
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3:21 - 3:22And then it starts up again
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3:22 - 3:24in the opposite direction
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3:24 - 3:26as energy leaves the warmer surface of your skin
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3:26 - 3:29to return to the universe around you,
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3:29 - 3:32that energy, neither created nor destroyed,
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3:32 - 3:34but ever shape-shifting,
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3:34 - 3:36the chameleon phoenix of our physical world.
- Title:
- All of the energy in the universe is... - George Zaidan and Charles Morton
- Description:
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View full lesson: http://ed.ted.com/lessons/all-of-the-energy-in-the-universe-is-george-zaidan-and-charles-morton
The energy in the universe never increases or decreases -- but it does move around a lot. Energy can be potential (like a stretched-out rubber band waiting to snap) or kinetic (like the molecules that vibrate within any substance). And though we can't exactly see it, every time we cook dinner or shiver on a cold night, we know it's there. George Zaidan and Charles Morton get excited about energy.
Lesson by George Zaidan and Charles Morton, animation by Pew36 Animation Studios.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 03:52
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Andrea McDonough edited English subtitles for All of the energy in the universe is... - George Zaidan and Charles Morton |