What is a one-sentence summary of the following article?
Add a second nut to the hook and bring the pendulum back to where you marked on the paper the first time. When you release the pendulum, start a stopwatch and count the number of oscillations for 1 minute. Repeat the process 5 times, then calculate your average.  Notice the difference in the number of oscillations and the average between 1 nut on the hook and 2 nuts on the hook. Add another nut and repeat the experiment to see if even more mass will affect the pendulum’s oscillations. Go back to just 1 nut on the hook, bring the string back about 10 inches (25 cm), and make a mark on the paper taped behind it so you can repeat the experiment from the same distance. Release the pendulum and count the number of oscillations for 1 minute. Repeat the process 5 times and calculate an average.  You may be surprised to learn that the distance (also called amplitude) does not affect the swing rate, or number of oscillations. Try the experiment again from 5 inches (13 cm) and find the average number of oscillations to see how much of a difference the distance makes. Slide the look off of the pencil and cut off 10 inches (25 cm) of string, tie another loop, and put it back on the pencil. Then bring the pendulum back about 10 inches (25 cm) and mark on the paper where you release it from. Repeat the experiment 5 times and find the average number of oscillations to see how the length of the string affects the pendulum.  Cut off another 10 inches (25 cm) of string to see the difference it makes on the average number of oscillations. The length from which a pendulum is suspended helps determine the speed and regularity of the swings, which is why pendulums have been used to keep time.

Summary:
Add a nut to the hook to see what difference the mass makes. Change the distance to see how it affects the oscillations. Cut off 10 inches (25 cm) of the string to see the effects.