# Pendulum Lab

## Question:

How will changing a property (the mass or string length) of the pendulum effect the pendulum's period?

## Background:

The background should include:

• Pendulum definition.
• Period definition.
• Definitions of potential and kinetic energy.
• Relationship of P.E. and K.E. to the pendulum system.
• List the factors that may influence the pendulum period.
• Student describes the factor that they have chosen to investigate. They may choose either pendulum length or mass.

## Prediction/Hypothesis:

If the length/mass is increased/decreased (select one) then the pendulum period will be longer/shorter (select one), because ______.

## Equipment:

Make a complete list of the equipment you will need.

• (1) protractor (angles of less than 20°)
• (2) 1 oz lead masses (you will have to measure the mass in grams)
• ( ) string (finished lengths in 10 cm increments: 10cm, 20cm, 30cm)
• ( ) _______________

## Procedure:

Write a step-by-step description of how you will perform the experiment. Use a list of numbered, short, concise sentences. Someone else should be able to duplicate your experiment using these instructions. The manipulated and responding variables are identified within the steps of the procedure. Two controlled variables are also identified as the student explains how and to what value they will be set to. Be sure to describe how to do the repeated trials. How are the masses of the fishing weights determined? How is the protractor used?

## Data:

The data section has three parts:

1. Data table.
2. Percentage change table with calculations for both the manipulated and responding variables.
1. Formula: percentage change = 100* ( final number - beginning number) / beginning number
2. Example: % change = 100 * (30 cm - 10 cm) / 10cm = 200%
3. A common error is to not pay attention to the parenthesis.
3. A graph of your data with the manipulated (independent) variable on the x-axis and the responding (dependent) variable on the y-axis.
4. A graph of the percentage change with the manipulated (independent) variable on the x-axis and the % change on the y-axis.
5. A labeled diagram (drawing) of the experimental setup.

## Conclusion:

The conclusion is a paragraph with the following:

1. Restate the prediction or hypothesis.
2. Clearly state whether the prediction/hypothesis was correct or give a correct answer to the investigative question.
3. Provide the range of data from high to low.
4. Explain how the data supports or rejects the hypothesis or answers the question.

In addition, the conclusion is the place to report any errors that occurred, list any variables that were not controlled, list what would be done differently if the experiment were repeated, and ask any additional questions that come up as result of the research.