Radioactive Decay

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Radioactive Decay
Half Life
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Mr. Steckle's
Half-Life Presentation
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Radioactive Dating gives scientists the ability
to assign something an absolute age
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In order to do this
Scientists use ISOTOPES
If an element has too many neutrons, the element
will be radioactive
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The unstable radioactive element will
disintegrate to a stable element
The stable element is called the DECAY PRODUCT
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The decay product is produced in a predictable
amount of time
This predictability gives scientists the ability
to assign a given material an ABSOLUTE AGE
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Example Carbon 14 6 protons 8 neutrons
Carbon 14 is unstable. It wants to decay to the
stable element Nitrogen 14
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Carbon 14
Nitrogen 14
Half-Life
5700 years
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original after each half life
Half-Lives
12.5
50
25
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Carbon 14 has a half-life of 5700 years.
This gives scientists the ability to accurately
date a carbon containing material up to 50,000
years
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If a material is older than 50,000 years,
scientists must use another radioactive element
Other radioactive isotopes are
Uranium 238 Potassium 40 Rubidium 87
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Examples
Uranium 238
Lead 206
Half-life
4,900,000,000 years
Argon 40
Potassium 40
Calcium 40
Half-life
1,300,000,000 years
Rubidium 87
Serium 87
Half- life
49,000,000,000
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Remember
You can always have half of a material. There is
a point when the amount of the original material
is to small to identify, but you will never have
zero original product.
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Generic Radioactivity graph
100 75 50 25 0
Percent of original radioactive element
1 2 3 4
5 6
of half lives
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In conclusion
Radioactive decay
Half-life
Decay product
Carbon 14
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.
Thank-you