How batteries work - Adam Jacobson
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0:07 - 0:09You probably know the feeling.
-
0:09 - 0:13Your phone utters
its final plaintive "bleep" -
0:13 - 0:15and cuts out in the middle of your call.
-
0:15 - 0:19In that moment, you may feel more
like throwing your battery across the room -
0:19 - 0:21than singing its praises,
-
0:21 - 0:25but batteries are a triumph of science.
-
0:25 - 0:28They allow smartphones
and other technologies to exist -
0:28 - 0:32without anchoring us
to an infernal tangle of power cables. -
0:32 - 0:36Yet even the best batteries
will diminish daily, -
0:36 - 0:40slowly losing capacity
until they finally die. -
0:40 - 0:41So why does this happen,
-
0:41 - 0:46and how do our batteries even store
so much charge in the first place? -
0:46 - 0:50It all started in the 1780s
with two Italian scientists, -
0:50 - 0:54Luigi Galvani and Alessandro Volta,
-
0:54 - 0:55and a frog.
-
0:55 - 0:59Legend has it that as Galvani
was studying a frog's leg, -
0:59 - 1:02he brushed a metal instrument
up against one of its nerves, -
1:02 - 1:05making the leg muscles jerk.
-
1:05 - 1:07Galvani called this animal electricity,
-
1:07 - 1:12believing that a type of electricity
was stored in the very stuff of life. -
1:12 - 1:14But Volta disagreed,
-
1:14 - 1:18arguing that it was the metal itself
that made the leg twitch. -
1:18 - 1:22The debate was eventually settled
with Volta's groundbreaking experiment. -
1:22 - 1:28He tested his idea with a stack
of alternating layers of zinc and copper, -
1:28 - 1:32separated by paper or cloth
soaked in a salt water solution. -
1:32 - 1:39What happened in Volta's cell is something
chemists now call oxidation and reduction. -
1:39 - 1:43The zinc oxidizes,
which means it loses electrons, -
1:43 - 1:49which are, in turn, gained by the ions in
the water in a process called reduction, -
1:49 - 1:51producing hydrogen gas.
-
1:51 - 1:54Volta would have been shocked
to learn that last bit. -
1:54 - 1:56He thought the reaction
was happening in the copper, -
1:56 - 1:58rather than the solution.
-
1:58 - 2:01None the less,
we honor Volta's discovery today -
2:01 - 2:06by naming our standard unit
of electric potential "the volt." -
2:06 - 2:12This oxidation-reduction cycle creates
a flow of electrons between two substances -
2:12 - 2:15and if you hook a lightbulb
or vacuum cleaner up between the two, -
2:15 - 2:17you'll give it power.
-
2:17 - 2:21Since the 1700s, scientists have improved
on Volta's design. -
2:21 - 2:27They've replaced the chemical solution
with dry cells filled with chemical paste, -
2:27 - 2:28but the principle is the same.
-
2:28 - 2:32A metal oxidizes,
sending electrons to do some work -
2:32 - 2:36before they are regained
by a substance being reduced. -
2:36 - 2:38But any battery has a finite
supply of metal, -
2:38 - 2:42and once most of it has oxidized,
the battery dies. -
2:42 - 2:47So rechargeable batteries give us
a temporary solution to this problem -
2:47 - 2:51by making the oxidation-reduction
process reversible. -
2:51 - 2:54Electrons can flow back
in the opposite direction -
2:54 - 2:56with the application of electricity.
-
2:56 - 3:00Plugging in a charger draws
the electricity from a wall outlet -
3:00 - 3:03that drives the reaction
to regenerate the metal, -
3:03 - 3:08making more electrons available
for oxidation the next time you need them. -
3:08 - 3:10But even rechargeable batteries
don't last forever. -
3:10 - 3:14Over time, the repetition of this process
causes imperfections -
3:14 - 3:20and irregularities in the metal's surface
that prevent it from oxidizing properly. -
3:20 - 3:23The electrons are no longer available
to flow through a circuit -
3:23 - 3:25and the battery dies.
-
3:25 - 3:27Some everyday rechargeable batteries
-
3:27 - 3:31will die after only hundreds
of discharge-recharge cycles, -
3:31 - 3:37while newer, advanced batteries
can survive and function for thousands. -
3:37 - 3:39Batteries of the future
may be light, thin sheets -
3:39 - 3:42that operate on the principles
of quantum physics -
3:42 - 3:46and last for hundreds
of thousands of charge cycles. -
3:46 - 3:49But until scientists find a way
to take advantage of motion -
3:49 - 3:52to recharge your cell battery,
like cars do, -
3:52 - 3:55or fit solar panels
somewhere on your device, -
3:55 - 3:57plugging your charger into the wall,
-
3:57 - 4:00rather than expending
one battery to charge another -
4:00 - 4:04is your best bet to forestall
that fatal "bleep."
- Title:
- How batteries work - Adam Jacobson
- Description:
-
View full lesson: http://ed.ted.com/lessons/why-batteries-die-adam-jacobson
Batteries are a triumph of science—they allow smartphones and other technologies to exist without anchoring us to an infernal tangle of power cables. Yet even the best batteries will diminish daily, slowly losing capacity until they finally die. Why does this happen, and how do our batteries even store so much charge in the first place? Adam Jacobson gives the basics on batteries.Lesson by Adam Jacobson, animation by FOX Animation Domination High-Def.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 04:20
Jenny Zurawell edited English subtitles for How batteries work - Adam Jacobson | ||
Jessica Ruby edited English subtitles for How batteries work - Adam Jacobson | ||
Jessica Ruby edited English subtitles for How batteries work - Adam Jacobson | ||
Jessica Ruby edited English subtitles for How batteries work - Adam Jacobson | ||
Jessica Ruby approved English subtitles for How batteries work - Adam Jacobson | ||
Jessica Ruby accepted English subtitles for How batteries work - Adam Jacobson | ||
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Jennifer Cody edited English subtitles for How batteries work - Adam Jacobson |