Do you know how scientists calculate the age of a fossil
to answer this, let's talk about
radioactive decay and carbon dating
You, I and everything around us are made of atom, each atom is made up of subatomic particles
Proton and neutron in the nucleus and electron orbiting around
Basing on the neutron to proton ratio
we may decide on the nuclear stability and
Radioactivity is a property of atoms that have unstable nuclei
these atoms will release energy and particles to gain more stable configuration and
This process is called decay
Radioactive decay can change the identity of an atom for example
Carbon-14 contains 6 proton and 8 neutron is the nucleus, is
Unstable and will decay into nitrogen
but
How does this equation help scientists know how old a fossil is?
Let's move on
carbon dating and a new concept
Half-life, there are more than one form of carbon carbon -12
Which is stable, make up 99% of carbon in the atmosphere and carbon-14 is radioactive
only occupies a tiny amount
carbon often exists in form of gases like carbon dioxide
plant absorbs carbon dioxide
by photosynthesis, this animal eats plants and take in Carbon 14 as well
this means that the ratio of carbon 14 to carbon 12
in the air, and in this plant
In this animal's body is the same and nearly constant at any given time
But what happens when the animal
die
stopped eating, right , and it
Stopped taking in new carbon, but carbon 14 in its body continue to decay into Nitrogen after about
5,700 years half of the amount of carbon 14 in its body will decay into nitrogen and
this period of time is called a half- life
After one half life, the animal only has half of the amount of carbon-14 in its body
After 2 halves -life, it only has a quarter after
Three halves life, it only has one eighth
By comparing the ratio of carbon 14 to carbon 12 in the air and in this animal's body
Scientists can calculate that how many years have passed since the animal died. That is about
Radioactivity and carbon dating. I hope you guy enjoy it, see ya
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