(The barrel is made deep enough so that we don't have to worry about water overflowing the rim.) Henry Morris argued that if we started filling up our empty barrel it would take 30,000 years to reach the equilibrium point.
Thus, he concluded, if our Earth were older than 30,000 years the incoming water should just equal the water leaking out.
The barrel represents the earth's atmosphere in which the carbon-14 accumulates.
The water leaking out the sides of the barrel represents the loss (mainly by radioactive decay) of the atmosphere's supply of carbon-14.
Bucha, who has been able to determine, using samples of baked clay from archeological sites, what the intensity of the earth's magnetic field was at the time in question.
(Strahler, 1987, p.156) The idea [that the fluctuating magnetic field affects influx of cosmic rays, which in turn affects C-14 formation rates] has been taken up by the Czech geophysicist, V.
When the dipole moment is strong, carbon-14 production is suppressed below normal; when it is weak, carbon-14 production is boosted above normal.
What the magnetic field does is to partially shield the earth from cosmic rays which produce carbon-14 high in the atmosphere.
Creationists don't want their readers to be distracted with problems like that -- unless the cat is already out of the bag and something has to be said.
Tree-ring dating (see Topic 27) gives us a wonderful check on the radiocarbon dating method for the last 8000 years.