3CarbonDating.ppt 100KB Jun 23 2011 10:24:00 AM
Carbon Dating
By: Kelly Davenport, John
Kolenda, Rosalie Tolentino, David
McCracken
Definition of Carbon Dating
Carbon
Dating: a chemical analysis used
to determine the age of organic materials
based on their content of the radioisotope
carbon 14; believed to be reliable up to
40,000 years
Based on the rate of decay of the carbon
isotope 14 (14C)
How Carbon14 is made
Cosmic rays enter the earth's
atmosphere. They then collide
with an atom in the
atmosphere, creating a
secondary cosmic ray in the
form of an energetic neutron.
These energetic neutrons
collide with nitrogen atoms.
When the neutrons collides a
nitrogen-14 (seven protons,
seven neutrons) atom turns
into a carbon 14 atom (six
protons, eight neutrons) and a
hydrogen atom (one proton,
zero neutrons).
How Carbon Dating Works
The carbon content of living matter is constantly
renewed so the proportion of carbon 12 to carbon 14 is
the same
The rate Carbon 14 forms seems to be constant.
Therefore by measuring the ratio between carbon 12 and
the carbon 14 in a dead organism and comparing it to
the ratio in living things, a measurement of time is made.
Because the rate of decay for carbon 14 is 57,000 years,
carbon dating is only reliable for dating things up to 60,
000 years old. As soon as a living organism dies, it stops
taking in new carbon.
Half Life of Carbon Dating
Half-Life
refers to the time taken
to lose half of radioactivity: the
time a radioactive substance
takes to lose half its
radioactivity through decay.
The Half-Life of Carbon 14 is
5730 years. For example, if a
relatively large sample of
Carbon 14 was left untouched
for 5730 years, half of it would
remain and the other half would
decay.
Half Life Analogy
Half
Life is to Carbon 14 as
exponentially decreasing over
time is to mathematics
Examples of Carbon Dating Uses
Carbon
Dating can be extremely useful to
archeologists when they need to know the
approximate date of a fossil or any other
object.
Some examples of when carbon dating is
used: to find the ages of trees, mummies,
fossils, or any other organic material
Bibliography
http://www.mnsu.edu/emuseum/archaeology
/dating/radio_carbon.html
http://science.howstuffworks.com/carbon14.htm
http://hyperphysics.phyastr.gsu.edu/hbase/nuclear/cardat.html
http://www.physlink.com/Education/AskEx
perts/ae403.cfm
By: Kelly Davenport, John
Kolenda, Rosalie Tolentino, David
McCracken
Definition of Carbon Dating
Carbon
Dating: a chemical analysis used
to determine the age of organic materials
based on their content of the radioisotope
carbon 14; believed to be reliable up to
40,000 years
Based on the rate of decay of the carbon
isotope 14 (14C)
How Carbon14 is made
Cosmic rays enter the earth's
atmosphere. They then collide
with an atom in the
atmosphere, creating a
secondary cosmic ray in the
form of an energetic neutron.
These energetic neutrons
collide with nitrogen atoms.
When the neutrons collides a
nitrogen-14 (seven protons,
seven neutrons) atom turns
into a carbon 14 atom (six
protons, eight neutrons) and a
hydrogen atom (one proton,
zero neutrons).
How Carbon Dating Works
The carbon content of living matter is constantly
renewed so the proportion of carbon 12 to carbon 14 is
the same
The rate Carbon 14 forms seems to be constant.
Therefore by measuring the ratio between carbon 12 and
the carbon 14 in a dead organism and comparing it to
the ratio in living things, a measurement of time is made.
Because the rate of decay for carbon 14 is 57,000 years,
carbon dating is only reliable for dating things up to 60,
000 years old. As soon as a living organism dies, it stops
taking in new carbon.
Half Life of Carbon Dating
Half-Life
refers to the time taken
to lose half of radioactivity: the
time a radioactive substance
takes to lose half its
radioactivity through decay.
The Half-Life of Carbon 14 is
5730 years. For example, if a
relatively large sample of
Carbon 14 was left untouched
for 5730 years, half of it would
remain and the other half would
decay.
Half Life Analogy
Half
Life is to Carbon 14 as
exponentially decreasing over
time is to mathematics
Examples of Carbon Dating Uses
Carbon
Dating can be extremely useful to
archeologists when they need to know the
approximate date of a fossil or any other
object.
Some examples of when carbon dating is
used: to find the ages of trees, mummies,
fossils, or any other organic material
Bibliography
http://www.mnsu.edu/emuseum/archaeology
/dating/radio_carbon.html
http://science.howstuffworks.com/carbon14.htm
http://hyperphysics.phyastr.gsu.edu/hbase/nuclear/cardat.html
http://www.physlink.com/Education/AskEx
perts/ae403.cfm