The most dangerous elements on the periodic table - Shannon Odell

456,034 views ใƒป 2024-08-06

TED-Ed


ืื ื ืœื—ืฅ ืคืขืžื™ื™ื ืขืœ ื”ื›ืชื•ื‘ื™ื•ืช ื‘ืื ื’ืœื™ืช ืœืžื˜ื” ื›ื“ื™ ืœื”ืคืขื™ืœ ืืช ื”ืกืจื˜ื•ืŸ.

ืชืจื’ื•ื: dana menahem ืขืจื™ื›ื”: zeeva livshitz
00:07
From 1952 to 1953, Sydney detectives investigated
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ื‘ืฉื ื™ื 1952-1953 ื—ืงืจื• ื‘ืœืฉื™ื ื‘ืกื™ื“ื ื™
00:12
a staggering number of murder and attempted murder cases
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ืžืกืคืจ ืžื“ื”ื™ื ืฉืœ ืžืงืจื™ ืจืฆื— ื•ื ื™ืกื™ื•ื ื•ืช ืจืฆื—
00:15
that were unrelated yet shared a common element:
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ืฉืœื ื”ื™ื• ืงืฉื•ืจื™ื ืืš ื—ืœืงื• ืืœืžื ื˜ ืžืฉื•ืชืฃ:
00:18
thallium poisoning.
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ื”ืจืขืœืช ืชืœื™ื•ื.
00:20
The secret to thallium toxicity lies in its structural similarity to potassiumโ€”
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ื”ืกื•ื“ ืœืจืขื™ืœื•ืช ื”ืชืœื™ื•ื ื˜ืžื•ืŸ ื‘ื“ืžื™ื•ืŸ ื”ืžื‘ื ื™ ืฉืœื• ืœืืฉืœื’ืŸ-
00:25
an element that helps regulate the body's fluids,
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ื”ื™ืกื•ื“ ื”ืžืกื™ื™ืข ื‘ื•ื•ื™ืกื•ืช ื ื•ื–ืœื™ ื”ื’ื•ืฃ,
00:27
initiate muscle contraction, and transmit nerve signals.
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ื™ื•ื–ื ื”ืชื›ื•ื•ืฆื•ืช ืฉืจื™ืจื™ื ื•ื”ืขื‘ืจืช ืื•ืชื•ืช ืขืฆื‘ื™ื™ื.
00:31
If even a small amount of thallium sneaks its way into the bodyโ€”
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ืื ืืคื™ืœื• ื›ืžื•ืช ืงื˜ื ื” ืฉืœ ืชืœื™ื•ื ืžืชื’ื ื‘ืช ืœื’ื•ืฃ -
00:35
for example, through a tainted tea or a slice of cakeโ€”
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ืœืžืฉืœ, ื“ืจืš ืชื” ื ื’ื•ืข ืื• ืคืจื•ืกืช ืขื•ื’ื”-
00:38
it easily supplants potassium,
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ื”ื™ื ืžื—ืœื™ืคื” ื‘ืงืœื•ืช ืืฉืœื’ืŸ,
00:40
causing the body to slowly and painfully shut down.
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ื•ื’ื•ืจืžืช ืœื’ื•ืฃ ืœื”ืื˜ ื•ืœื›ื‘ื•ืช ืœืื˜ ื•ื‘ื›ืื‘
00:44
At the time, thallium's risks were well known,
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ื‘ืื•ืชื” ืชืงื•ืคื”, ื”ืกื™ื›ื•ื ื™ื ืฉืœ ืชืœื™ื•ื ื”ื™ื• ื™ื“ื•ืขื™ื ื”ื™ื˜ื‘,
00:47
so how were the perpetrators able to get their hands on such a lethal element?
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ืื– ืื™ืš ื”ืฆืœื™ื—ื• ื”ืขื‘ืจื™ื™ื ื™ื ืœืฉื™ื ืืช ื™ื“ื™ื”ื ืขืœ ื—ื•ืžืจ ืงื˜ืœื ื™ ืฉื›ื–ื”?
00:51
And thallium isn't the only dangerous element on the periodic table.
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ื•ืชืœื™ื•ื ืื™ื ื• ื”ื™ืกื•ื“ ื”ืžืกื•ื›ืŸ ื”ื™ื—ื™ื“ ื‘ื˜ื‘ืœื” ื”ืžื—ื–ื•ืจื™ืช.
00:55
Within this tabular array loom several potential threats,
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ื‘ืชื•ืš ืžืขืจืš ื˜ื‘ืœืื™ ื–ื” ืžืชื ืฉืื™ื ื›ืžื” ืื™ื•ืžื™ื ืคื•ื˜ื ืฆื™ืืœื™ื™ื,
00:58
each with their own unique method of imposing destruction.
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ืฉืœื›ืœ ืื—ื“ ืžื”ื ืฉื™ื˜ื” ื™ื™ื—ื•ื“ื™ืช ืžืฉืœื• ืœื”ื˜ืœืช ื”ืจืก.
01:01
Some elements, like thallium, are dangerous due to their toxicity.
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ื™ืกื•ื“ื•ืช ืžืกื•ื™ืžื™ื, ื›ืžื• ืชืœื™ื•ื, ืžืกื•ื›ื ื™ื ื‘ื’ืœืœ ืจืขื™ืœื•ืชื.
01:06
Once they enter the body,
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ื‘ืจื’ืข ืฉื”ื ื ื›ื ืกื™ื ืœื’ื•ืฃ,
01:07
they wreak havoc on the biological systems that keep us alive.
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ื”ื ื–ื•ืจืขื™ื ื”ืจืก ื‘ืžืขืจื›ื•ืช ื”ื‘ื™ื•ืœื•ื’ื™ื•ืช ืฉืžื—ื–ื™ืงื•ืช ืื•ืชื ื• ื‘ื—ื™ื™ื.
01:11
Lead, for example, switches places with the body's essential metals like calcium,
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ืขื•ืคืจืช, ืœืžืฉืœ, ืžื—ืœื™ืคื” ืžืงื•ืžื•ืช ืขื ื”ืžืชื›ื•ืช ื”ื—ื™ื•ื ื™ื•ืช ืฉืœ ื”ื’ื•ืฃ ื›ืžื• ืกื™ื“ืŸ,
01:15
in turn disrupting neuronal communication in the brain.
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ืฉื‘ืชื•ืจื” ืžืฉื‘ืฉืช ืืช ื”ืชืงืฉื•ืจืช ื”ืขืฆื‘ื™ืช ื‘ืžื•ื—.
01:18
Traveling through the bloodstream, it also generates toxic levels of molecules
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ื›ืฉื”ื•ื ื ื•ืกืข ื‘ื–ืจื ื”ื“ื, ื”ื•ื ืžื™ื™ืฆืจ ื’ื ืจืžื•ืช ืจืขื™ืœื•ืช ืฉืœ ืžื•ืœืงื•ืœื•ืช
01:22
known as reactive oxygen species, which over time can stress and kill cells.
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ื”ืžื›ื•ื ื•ืช ืžื™ื ื™ ื—ืžืฆืŸ ืชื’ื•ื‘ืชื™ื™ื, ืืฉืจ ืœืื•ืจืš ื–ืžืŸ ื™ื›ื•ืœื™ื ืœื”ืœื—ื™ืฅ ื•ืœื”ืจื•ื’ ืชืื™ื.
01:28
Mercury's toxicity was made famous in the 19th century
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ื”ืจืขื™ืœื•ืช ืฉืœ ื”ื›ืกืคื™ืช ื”ืชืคืจืกืžื” ื‘ืžืื” ื” -19
01:31
due to its widespread use in felt hat production.
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ื‘ืฉืœ ื”ืฉื™ืžื•ืฉ ื”ื ืจื—ื‘ ื‘ื™ื™ืฆื•ืจ ื›ื•ื‘ืขื™ ืœื‘ื“.
01:35
Prolonged exposure made hat makers ill
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ื—ืฉื™ืคื” ืžืžื•ืฉื›ืช ื’ืจืžื” ืœื™ืฆืจื ื™ ื›ื•ื‘ืขื™ื ืœื—ืœื•ืช
01:37
with what was later known as "Mad Hatter" disease,
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ื‘ืžื” ืฉื ื•ื“ืข ืžืื•ื—ืจ ื™ื•ืชืจ ื›ืžื—ืœืช โ€œื”ื›ื•ื‘ืขืŸ ื”ืžื˜ื•ืจืฃโ€œ,
01:40
with symptoms that included personality changes,
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ืขื ืชืกืžื™ื ื™ื ืฉื›ืœืœื• ืฉื™ื ื•ื™ื™ื ื‘ืื™ืฉื™ื•ืช, ื”ืคืจืขื•ืช
01:43
emotional disturbances, and tremors.
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ืจื’ืฉื™ื•ืช ื•ืจืขื™ื“ื•ืช.
01:46
Mercury is quick to react with certain parts of proteins
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ื›ืกืคื™ืช ืžื”ื™ืจื” ืœื”ื’ื™ื‘ ืขื ื—ืœืงื™ื ืžืกื•ื™ืžื™ื ืฉืœ ื—ืœื‘ื•ื ื™ื
01:49
found throughout the body.
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ื”ื ืžืฆืื™ื ื‘ื›ืœ ื”ื’ื•ืฃ.
01:50
And upon binding, mercury twists the proteins into different shapes,
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ื•ืขื ื”ื™ืงืฉืจื•ืช, ื”ื›ืกืคื™ืช ืžืกื•ื‘ื‘ืช ืืช ื”ื—ืœื‘ื•ื ื™ื ืœืฆื•ืจื•ืช ืฉื•ื ื•ืช,
01:55
rendering them useless.
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ืžื” ืฉื”ื•ืคืš ืื•ืชื ืœื—ืกืจื™ ืชื•ืขืœืช.
01:57
Some elements are dangerous because of how they respond, react, or even explode
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ื™ืกื•ื“ื•ืช ืžืกื•ื™ืžื™ื ืžืกื•ื›ื ื™ื ื‘ื’ืœืœ ื”ืื•ืคืŸ ืฉื‘ื• ื”ื ืžืฉื™ื‘ื™ื ืžื’ื™ื‘ื™ื, ืื• ืืคื™ืœื• ืžืชืคื•ืฆืฆื™ื
02:02
in the outside environment.
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ื‘ืกื‘ื™ื‘ื” ื”ื—ื™ืฆื•ื ื™ืช.
02:03
Top reactive elements reside in the first column of the periodic table
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ื™ืกื•ื“ื•ืช ืชื’ื•ื‘ืชื™ื™ื ืžื•ื‘ื™ืœื™ื ืฉื•ื›ื ื™ื ื‘ืขืžื•ื“ื” ื”ืจืืฉื•ื ื” ืฉืœ ื”ื˜ื‘ืœื” ื”ืžื—ื–ื•ืจื™ืช
02:07
and are known as alkali metals.
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ื•ื™ื“ื•ืขื™ื ื›ืžืชื›ื•ืช ืืœืงืœื™ื•ืช.
02:10
They're rarely found in their pure elemental form,
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ืœืขืชื™ื ืจื—ื•ืงื•ืช ื”ื ื ืžืฆืื™ื ื‘ืฆื•ืจืชื ื”ื™ืกื•ื“ื™ืช ื”ื˜ื”ื•ืจื”,
02:12
as alkalis readily donate the single electron in their outer shell
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ืฉื›ืŸ ืืœืงืœื™ื•ืช ืชื•ืจืžื•ืช ื‘ืงืœื•ืช ืืช ื”ืืœืงื˜ืจื•ืŸ ื”ื™ื—ื™ื“ ื‘ืงืœื™ืคื” ื”ื—ื™ืฆื•ื ื™ืช ืฉืœื”ื
02:16
to whatever's around to form more stable ionic compounds.
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ืœื›ืœ ืžื” ืฉื™ืฉ ื‘ืกื‘ื™ื‘ื” ื›ื“ื™ ืœื™ืฆื•ืจ ืชืจื›ื•ื‘ื•ืช ื™ื•ื ื™ื•ืช ื™ืฆื™ื‘ื•ืช ื™ื•ืชืจ.
02:19
This can lead to violent resultsโ€”
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ื–ื” ื™ื›ื•ืœ ืœื”ื•ื‘ื™ืœ ืœืชื•ืฆืื•ืช ืืœื™ืžื•ืช-
02:21
pure cesium, for example, bursts into flames when exposed to air,
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ืฆื–ื™ื•ื ื˜ื”ื•ืจ, ืœืžืฉืœ, ืžืชืคืจืฅ ื‘ืœื”ื‘ื•ืช ื›ืืฉืจ ื”ื•ื ื ื—ืฉืฃ ืœืื•ื•ื™ืจ,
02:26
and explodes when dropped in water.
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ื•ืžืชืคื•ืฆืฅ ื›ืืฉืจ ื”ื•ื ื ื•ืคืœ ืœืžื™ื.
02:28
Francium is likely the most reactive alkali
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ืคืจื ืฆื™ื•ื ื”ื•ื ื›ื›ืœ ื”ื ืจืื” ื”ืืœืงืœื™ ื”ืชื’ื•ื‘ืชื™ ื‘ื™ื•ืชืจ
02:31
based on its position in the periodic table,
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ื‘ื”ืชื‘ืกืก ืขืœ ืžื™ืงื•ืžื• ื‘ื˜ื‘ืœื” ื”ืžื—ื–ื•ืจื™ืช
02:33
but we don't know for sure.
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ืืš ืื™ื ื ื• ื™ื•ื“ืขื™ื ื‘ื•ื•ื“ืื•ืช.
02:35
With a half-life of 22 minutes at most,
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ืขื ืžื—ืฆื™ืช ื—ื™ื™ื ืฉืœ 22 ื“ืงื•ืช ืœื›ืœ ื”ื™ื•ืชืจ,
02:37
it's thought that less than an ounce exists on Earth at any one time.
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ื—ื•ืฉื‘ื™ื ืฉืคื—ื•ืช ืžืื•ื ืงื™ื” ืงื™ื™ืžืช ืขืœ ื›ื“ื•ืจ ื”ืืจืฅ ื‘ื›ืœ ื–ืžืŸ ื ืชื•ืŸ.
02:42
But perhaps the most threatening elements are those that silently emit.
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ืื‘ืœ ืื•ืœื™ ื”ืืœืžื ื˜ื™ื ื”ืžืื™ื™ืžื™ื ื‘ื™ื•ืชืจ ื”ื ืืœื” ื”ืคื•ืœื˜ื™ื ื‘ืฉืงื˜.
02:46
Known as radioactive elements,
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ื”ื—ื•ืžืจื™ื, ื”ืžื›ื•ื ื™ื ื™ืกื•ื“ื•ืช ืจื“ื™ื•ืืงื˜ื™ื‘ื™ื™ื,
02:48
the substances readily release energy, or decay,
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ืžืฉื—ืจืจื™ื ื‘ืงืœื•ืช ืื ืจื’ื™ื”, ืื• ืžืชืคื•ืจืจื™ื,
02:52
due to their highly unstable nuclear composition.
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ื‘ื’ืœืœ ื”ื”ืจื›ื‘ ื”ื’ืจืขื™ื ื™ ื”ื‘ืœืชื™ ื™ืฆื™ื‘ ืฉืœื”ื.
02:56
This reactive nature is what's harnessed to create
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ื”ืื•ืคื™ ื”ืชื’ื•ื‘ืชื™ ื”ื–ื” ื”ื•ื ืžื” ืฉื ืจืชื ืœื™ืฆื™ืจืช
02:58
some of the world's most dangerous nuclear weapons.
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ื›ืžื” ืžื”ื ืฉืงื™ื ื”ื’ืจืขื™ื ื™ื ื”ืžืกื•ื›ื ื™ื ื‘ื™ื•ืชืจ ื‘ืขื•ืœื.
03:01
Radioactive elements typically emit energy in the form of alpha particles,
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ืืœืžื ื˜ื™ื ืจื“ื™ื•ืืงื˜ื™ื‘ื™ื™ื ืคื•ืœื˜ื™ื ื‘ื“ืจืš ื›ืœืœ ืื ืจื’ื™ื” ื‘ืฆื•ืจื” ืฉืœ ื—ืœืงื™ืงื™ ืืœืคื,
03:06
beta particles, neutrons, or electromagnetic radiation.
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ื—ืœืงื™ืงื™ ื‘ื˜ื, ื ื•ื™ื˜ืจื•ื ื™ื ืื• ืงืจื™ื ื” ืืœืงื˜ืจื•ืžื’ื ื˜ื™ืช.
03:10
While all dangerous,
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ื‘ืขื•ื“ ืฉื›ื•ืœื ืžืกื•ื›ื ื™ื,
03:12
alpha particles, which consist of two neutrons and protons
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ื—ืœืงื™ืงื™ ื”ืืœืคื ื”ืžื•ืจื›ื‘ื™ื ืžืฉื ื™ ื ื•ื™ื˜ืจื•ื ื™ื ื•ืคืจื•ื˜ื•ื ื™ื
03:15
bound tightly together,
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ื”ืงืฉื•ืจื™ื ื–ื” ืœื–ื”,
03:16
can be particularly hazardous.
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ื™ื›ื•ืœื™ื ืœื”ื™ื•ืช ืžืกื•ื›ื ื™ื ื‘ืžื™ื•ื—ื“.
03:19
Heavy and positively charged,
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ื›ื‘ื“ื™ื ื•ื˜ืขื•ื ื™ื ื—ื™ื•ื‘ื™ืช,
03:21
if alpha particles find their way into the body,
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ืื ื—ืœืงื™ืงื™ ืืœืคื ืžื•ืฆืื™ื ืืช ื“ืจื›ื ืœื’ื•ืฃ,
03:23
they can easily bombard and kill any cell in their path.
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ื”ื ื™ื›ื•ืœื™ื ื‘ืงืœื•ืช ืœื”ืคืฆื™ืฅ ื•ืœื”ืจื•ื’ ื›ืœ ืชื ื‘ื“ืจื›ื.
03:27
In fact, it's theorized that a single gram of one alpha emitter, polonium,
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ืœืžืขืฉื”, ื™ืฉ ืชื™ืื•ืจื™ื” ืฉื’ืจื ื‘ื•ื“ื“ ืฉืœ ืืœืคื ืคื•ืœื˜ ืคื•ืœื•ื ื™ื•ื ืื—ื“,
03:32
could kill upwards of 50 million people.
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ืฉื™ื›ื•ืœ ืœื”ืจื•ื’ ืœืžืขืœื” ืž -50 ืžื™ืœื™ื•ืŸ ืื ืฉื™ื.
03:35
Polonium was first discovered by Marie Curie,
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ืคื•ืœื•ื ื™ื•ื ื”ืชื’ืœื” ืœืจืืฉื•ื ื” ืขืœ ื™ื“ื™ ืžืืจื™ ืงื™ืจื™,
03:38
and tragically her daughter, researcher Irene Joliot-Curie,
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ื•ื‘ืื•ืคืŸ ื˜ืจื’ื™ ื‘ืชื”, ื”ื—ื•ืงืจืช ืื™ื™ืจื™ืŸ ื’โ€™ื•ืœื™ื•ื˜-ืงื™ืจื™,
03:42
may have been one of its first victims after she was exposed in a lab accident.
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ื”ื™ื™ืชื” ืื•ืœื™ ืื—ื“ ื”ืงื•ืจื‘ื ื•ืช ื”ืจืืฉื•ื ื™ื ืฉืœื• ืœืื—ืจ ืฉื ื—ืฉืคื” ื‘ืชืื•ื ืช ืžืขื‘ื“ื”.
03:47
Polonium is rare in nature with few commercial uses,
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ืคื•ืœื•ื ื™ื•ื ื”ื•ื ื ื“ื™ืจ ื‘ื˜ื‘ืข ืขื ืžืขื˜ ืฉื™ืžื•ืฉื™ื ืžืกื—ืจื™ื™ื,
03:50
so only a small amount is synthesized each year.
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ื•ืœื›ืŸ ืจืง ื›ืžื•ืช ืงื˜ื ื” ืžืกื•ื ืชื–ืช ืžื“ื™ ืฉื ื”.
03:54
Thallium, on the other hand, wasn't so difficult to find
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ืชืœื™ื•ื, ืœืขื•ืžืช ื–ืืช, ืœื ื”ื™ื” ื›ืœ ื›ืš ืงืฉื” ืœืžืฆื•ื
03:57
in the early 1950s in Austalia.
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ื‘ืชื—ื™ืœืช ืฉื ื•ืช ื”ื—ืžื™ืฉื™ื ื‘ืื•ืกื˜ืœื™ื”.
03:59
At the time, Sydney was plagued with chronic rat infestations.
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ื‘ืื•ืชื” ืชืงื•ืคื”, ืกื™ื“ื ื™ ืกื‘ืœื” ืžืฉืจื™ืฆื•ืช ื›ืจื•ื ื™ื•ืช ืฉืœ ื—ื•ืœื“ื•ืช.
04:03
And thallium was the main ingredient in the popular and cheap
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ื•ืชืœื™ื•ื ื”ื™ื” ื”ืžืจื›ื™ื‘ ื”ืขื™ืงืจื™ ื‘ืจืขืœ ื”ืขื›ื‘ืจื™ื ื”ืคื•ืคื•ืœืจื™ ื•ื”ื–ื•ืœ
04:06
rat poison called Thall-Rat.
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ื”ื ืงืจื ื˜ืืœ-ืขื›ื‘ืจื•ืฉ.
04:09
Thankfully, detectives were able to connect the dots,
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ืœืžืจื‘ื” ื”ืžื–ืœ, ื”ื‘ืœืฉื™ื ื”ืฆืœื™ื—ื• ืœื—ื‘ืจ ืืช ื”ื ืงื•ื“ื•ืช,
04:12
and in 1953 Australian Parliament effectively banned all sale of thallium.
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ื•ื‘ืฉื ืช 1953 ื”ืคืจืœืžื ื˜ ื”ืื•ืกื˜ืจืœื™ ืืกืจ ืœืžืขืฉื” ืขืœ ื›ืœ ืžื›ื™ืจืช ืชืœื™ื•ื.
ืขืœ ืืชืจ ื–ื”

ืืชืจ ื–ื” ื™ืฆื™ื’ ื‘ืคื ื™ื›ื ืกืจื˜ื•ื ื™ YouTube ื”ืžื•ืขื™ืœื™ื ืœืœื™ืžื•ื“ ืื ื’ืœื™ืช. ืชื•ื›ืœื• ืœืจืื•ืช ืฉื™ืขื•ืจื™ ืื ื’ืœื™ืช ื”ืžื•ืขื‘ืจื™ื ืขืœ ื™ื“ื™ ืžื•ืจื™ื ืžื”ืฉื•ืจื” ื”ืจืืฉื•ื ื” ืžืจื—ื‘ื™ ื”ืขื•ืœื. ืœื—ืฅ ืคืขืžื™ื™ื ืขืœ ื”ื›ืชื•ื‘ื™ื•ืช ื‘ืื ื’ืœื™ืช ื”ืžื•ืฆื’ื•ืช ื‘ื›ืœ ื“ืฃ ื•ื™ื“ืื• ื›ื“ื™ ืœื”ืคืขื™ืœ ืืช ื”ืกืจื˜ื•ืŸ ืžืฉื. ื”ื›ืชื•ื‘ื™ื•ืช ื’ื•ืœืœื•ืช ื‘ืกื ื›ืจื•ืŸ ืขื ื”ืคืขืœืช ื”ื•ื•ื™ื“ืื•. ืื ื™ืฉ ืœืš ื”ืขืจื•ืช ืื• ื‘ืงืฉื•ืช, ืื ื ืฆื•ืจ ืื™ืชื ื• ืงืฉืจ ื‘ืืžืฆืขื•ืช ื˜ื•ืคืก ื™ืฆื™ืจืช ืงืฉืจ ื–ื”.

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