According to the Newtonian formula for a simple pendulum, the period of a pendulum is inversely
proportional to the square root of g , the gravitational field strength. Einstein?s theory of
general relativity leads to the result that time slows down where gravity is intense. The two claims
look contradictory and can muddle student and teacher alike. There is, however, no real paradox.
This article, which aims to clarify the conceptual issues, identifies two sources of confusion. One
is a failure to distinguish a pendulum from a pendulum clock. The other is a failure to distinguish
between two distinct gravitational fields.