This applet simulates the swinging of a pendulum and calculates its period.
Click anywhere in the applet to start the pendulum swinging.
Please note that this applet is not an accurate time-measuring device. The speed that this pendulum swings depends on the speed of your computer.

If the applet does not appear, please try the following:
(1) Download the Java software from
(2) Go to the menu: Tools > Turn off Pop-Up Blocker.
(3) Tools > Internet Options > Advanced > Security > Allow Active Contents.
(4) Start Menu > All Programs > Java > Configure Java > Security and then add this website to the Exception Site List.

The period of oscillation T of a pendulum is given by:
T = 2 π l
where l = length of pendulum and g = acceleration due to gravity.

As the length of the pendulum increases, its period increases.

Right-click here to download this page and the Java Class File.