Today this fact demonstrates conservation of energy, a principle not yet discovered in Galileo's time. As a recreation, pendulums were released from different heights. The height the pendulum returned to was noted and compared to the release height. No quantitative measurements were made, but in every trial, the pendulum's return height was very close to its release height. The estimated difference between the heights was no more that 3 mm for the range of string lengths used.
All pendulums eventually come to rest with the lighter ones coming to rest faster.
Galileo noted that lighter pendulums come to rest faster. As a test of this observation, two pendulums, nearly identical except for their bobs of different weights, were released at the same time and height. A bob of lead was hung with a string length of 28.9 cm. A bob of cork was hung to hang at 29.0 cm. The two were released at the same time after being pulled back about 5 degrees.