Figure 19.5, curve C, shows the dipole field strength calculated from measurements of magnetism of lava flows and of artifacts such as pottery and bricks, whose age can be determined.The curve is roughly fitted to mean values determined about every 500 to 1,000 years...

(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.

We stick the garden hose in and turn it on full blast.

The water coming out of the hose is analogous to the continuous production of carbon-14 atoms in the upper atmosphere.

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.

Even before the tree-ring calibration data were available to them, he and the archeologist, Evzen Neustupny, were able to suggest how much this would affect the radiocarbon dates.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.That is, the equilibrium point should have long since been reached given the present rate of carbon-14 production and the old age of the earth.The next step in Henry Morris' argument was to show that the water level in our barrel analogy was not in equilibrium, that considerably more water was coming in than leaking out.To that end, he quoted some authorities, including Richard Lingenfelter.