This resemblance is used in chemical and biological research, in a technique called carbon labeling: carbon-14 atoms can be used to replace nonradioactive carbon, in order to trace chemical and biochemical reactions involving carbon atoms from any given organic compound.
These are relatively low energies; the maximum distance traveled is estimated to be 22 cm in air and 0.27 mm in body tissue.
Production rates vary because of changes to the cosmic ray flux caused by the heliospheric modulation (solar wind and solar magnetic field), and due to variations in the Earth's magnetic field.
The latter can create significant variations in The New Zealand curve is representative for the Southern Hemisphere, the Austrian curve is representative for the Northern Hemisphere.
The rates of disintegration of potassium-40 and carbon-14 in the normal adult body are comparable (a few thousand disintegrated nuclei per second).
This is small compared to the doses from potassium-40 (0.39 m Sv/year) and radon (variable).
Carbon-14 can be used as a radioactive tracer in medicine.