Name______Period______Date______

Pendulum Lab

Background: Pendula (plural of pendulum) have been used for many years. Galileo Galilei is credited as the first European to study pendula. He discovered that their regularity could be used to keep time. The pendulum follows simple mathematical rules relating to gravity and is very consistent in its behavior.

Materials in Kit:

Pre-measured pendulum, string, large washers, stopwatch, protractor

1.  Pre-lab Questions:

·  What causes a pendulum to swing down? ______

·  Why does a pendulum swing back up? ______

·  Give an example of a pendulum you have seen or used:______

  1. Research Question #1: How does the length of a pendulum affect the period?

·  Independent Variable: (What one thing are you changing?) Length of the string

·  Dependent Variable: (What are you measuring?) # of swings in 15 seconds

·  Control Variables: (What will you keep the same?) Mass of the pendulum bob, angle

  1. Hypothesis: Write a hypothesis using the variables listed above.

If:

then:

because (your claim)

4.  Data: Length of pendulum string in centimeters:______

# of swings in 15 seconds

#1 / #2 / #3 / #4 / #5 / Average

Tape your pendulum up on the front board in the correct length position. (Data = Evidence)

Copy ALL of the data into the following graph:

20 cm / 30 cm / 40 cm / 50 cm / 60 cm / 70 cm / 80 cm / 90 cm / 100 cm / 110 cm / 120 cm
Length of Pendulum String
  1. Analysis & Conclusion: Complete the following Claim & Evidence T-Chart

Claim / Evidence
  1. Researchable Question #2: What other factors affect the period of a pendulum (# of swings in 15 seconds)?

Experimental Design: Design an experiment that looks at a different variable. For example,

·  What happens to the period of the pendulum if I increase the mass of the bob (end of pendulum)?

·  What happens to the period of the pendulum if I put mass along the length of the pendulum?

·  What happens to the period of the pendulum if I change the starting angle?

Variables:

·  Independent Variable: (What one thing are you changing?) ______

·  Dependent Variable: (What are you measuring?) # of swings in 15 seconds

·  Control Variables: (What will you keep the same?) ______

  1. Hypothesis #2: Write a hypothesis using the variables you selected above.

If:

then:

because (your claim)

8.  Data: Independent Variable:______

# of swings in 15 seconds

Independent Variable: / #1 / #2 / #3 / #4 / Average
  1. Analysis & Conclusion: Complete the following Claim & Evidence T-Chart

Claim / Evidence

Conclusion:

  1. Explain why a line graph was the best graph to use for the data collected
  1. What did you learn from your experiment? (Write at least 3 sentences.)
  1. What are some possible mistakes or errors that were made during the experiment? How might these errors affect the results of the experiment? What did you do to reduce experimental errors? (Write at least 2 sentences.)