Home‎ > ‎Waves‎ > ‎Pendula‎ > ‎

Combo Pendulum Lab

 Combo Pendulum LabPurpose:The purpose of this activity is to investigate the different factors that affect the rate at which a pendulum oscillates.   Info:You will be testing how angle, mass, initial velocity, length and planet all effect the period and frequency of a pendulum.Pendulum length is measured from the point of oscillation to the center of the pendulum bob. Pendulum angle is measured by looking at how far the string has been pulled back from the vertical. An oscillation is defined to be one complete back and forth motion of the pendulum bob. Frequency is a measure of the number of cycles per second (f = #cycles/time)Period is defined as the time it takes to make one complete cycle (T = 1/f)Part 1: Angle (Virtual)Open this pendulum program in a new tab by holding down the apple key and clicking on this link.Using the pendulum program, hit the begin button and then set the length to length number 10.  Record the value of this length somewhere in your lab book.Click on the 10° label to start your pendulum with a 10° amplitude.  Count out 5 oscillations and stop the clock. Calculate the period of the pendulum and record this in a table that lists angle and period.While keeping all other factors constant click on the 20° label to start your pendulum with a 20° amplitude.  Again count out 5 oscillations and record the angle and the period of the pendulum.Continue this process for angles of 30° and 40°.Use the graphing program found here to create a graph of period vs. angle.Make a statement telling how the angle of release affects the time it takes for a pendulum to complete an oscillation.Part 2: Length (Live)For this part you will be using the pendulum apparatus at your desk to determine the number of oscillations that pendulum makes in 60 seconds.  Put a 50 gram mass on your string and set the length of the pendulum (pivot to center of mass) to 1.0 m.  Give your pendulum a small to moderate displacement and count the number of oscillations in one minute.Record your oscillation value for each different length. Find the frequency and period of each length pendulum.  Use the graphing program found here  to create a graph of period vs. length.Write down your equation that relates the length of the pendulum to its period.Give your individual data to your teacher so they can get a class average.Make a statement telling how the length of the pendulum affects the time it takes for a pendulum to complete an oscillation.Part 3: Mass (Live)Set the length of your pendulum at 75 cm and put a 100 gram mass on the pendulum.  Remember the length is measured to the middle of the mass.Pull your mass back a small amount (about 10°) and allow it to oscillate.  Time it for 10 oscillations and calculate the period.  While keeping all other factors change the mass to 50 grams and then finally to 20 grams.Use the graphing program found here to create a graph of period vs. mass.Make a statement telling how the mass of the pendulum affects the time it takes for a pendulum to complete an oscillation.Part 4: Planet (Virtual)Go back into the pendulum program and make sure the length of the pendulum is set to length #5 and the mass to 500 g.Set your mass into oscillation and time it to get the period.  Repeat this for each of the other heavenly bodies that you can access using this program.Get the accelerations due to gravity for each of the bodies from your teacher.Make a statement telling how the acceleration of the pendulum affects the time it takes for a pendulum to complete an oscillation.When you are done all four parts, make sure you submit your answers here.Things to have in your lab book:PurposeA picture of the lab set up. Data Tables, graphs and equations for all parts of the lab.An equation that relates length of pendulum to the period of the pendulum.