Pendulum Period
Sections
1. Setup
2. Hypothesis
3. Hardware Check
4. Changing Mass
5. Changing Length
6. Understanding
1. Setup
 InstructionsRead the introduction The period of a pendulum is how long it takes for it to go through a full swing. If we start with the pendulum suspended on one side and release it, then this is how long it takes to swing to the other side and back. We're going to observe how changing the mass and the length of the pendulum affects the period.Connect the pendulum sensor to digital pin 2 of your Arduino. 2. Hypothesis
 InstructionsSelect a hypotheses for each parameter GoalsSelect a hypotheses for varying the mass. Select a hypotheses for varying the length. The next sections will use a sensor to time the period of a pendulum. The sensor will measure how long it takes for the pendulum to complete one half of a full swing, or period. Then we'll average a few half periods to get a value for the full period. This will help up smooth out small differences so we can see the overall picture better. Before we start the experiment, let's form hypotheses for the behavior of the pendulum when we change its mass or length. When the mass of the pendulum increases, the period will Increase   Decrease   Stay the same   When the length of the pendulum increases, the period will Increase   Decrease   Stay the same
3. Hardware Check
 GoalsArduino plugged in and Infrared Pendulum Sensor connected to digital pin 2. Please plug in your Arduino if you haven't already and attach an Infrared Pendulum Sensor to digital pin 2.
4. Changing Mass
Each washer is about 10 grams. So for the 100 gram row in the table you'll add 10 washers to the pendulum.
Here's the procedure we'll follow:
1. Adjust Mass of your pendulum to match the value in the first row of the table.
2. Hold the pendulum off to one side until `Half Period` reads 0. This will reset the sensor.
3. Click `Select` for the first row in the data table.
4. Release the pendulum gently.
Repeat this process for the other rows in the table. When enough data has been gathered, the pendulum period will be filled in for you. You can re-record data for a row as many times as you like.

Half Period (ms)
0
Select Mass (g) Period

5. Changing Length
In this section switch back to 10 washers on the pendulum. We'll change the length, but keep the weight the same.

The pendulum rod is 30 cm long. For the other lengths in the table, just clip the washers higher on the rod at the listed length. For the 18 cm row in the table, clip the washers so they're 18 cm from the top of the pendulum rod.
Here's the procedure we'll follow:
1. Adjust Length of your pendulum to match the value in the first row of the table.
2. Hold the pendulum off to one side until `Half Period` reads 0. This will reset the sensor.
3. Click `Select` for the first row in the data table.
4. Release the pendulum gently.
Repeat this process for the other rows in the table. When enough data has been gathered, the pendulum period will be filled in for you. You can re-record data for a row as many times as you like.

Half Period (ms)
0
Select Length (cm) Period