Pendulum Activity

Today you will be making your own pendulum to use in experiments! In these experiments you will be determining what variables affect the number of times a pendulum swings back and forth in 30 seconds.

Points to remember: Measurement should be from end of paperclip to end of loop, regardless of how large a loop you made. Keep the meter stick on your desk so you can measure repeatedly while making your swinger. Exact measurement is very important!

Construct your “control” pendulum using the directions provided.

Predicition:

How many swings do you think the controlled pendulum will make in 30 seconds?

Experiment:

  1. Tape a pencil securely to a desk table so that the blunt end of pencil sticks over the edge a few centimeters
  2. Hang the swinger loop over the eraser end of the pencil.
  3. Decide as a group how high to hold the penny for release.
  4. Determine what counts as a swing to be counted. (To and fro equals one swing).
  5. Set one person to time 30 seconds using stop watch and the other person to release the penny and count the swings.
  6. Record the number of swings, repeat 3 times for accurate result.

Data Table:

Trial / Number of Swings
1
2
3
Mean

Now that you have had practice with your pendulum, it is time to test what variables change the number of swings that a pendulum takes in 30 seconds.

Angle of release

Predicition:

How do you think changing the angle of release will affect the number of swings the pendulum makes?

What is your independent variable?

What is your dependent variable?

Experiment

  1. Instead of releasing the penny straight out (parallel to the floor) release the swinger at a 45 degree angle from the top of the desk, keeping all the other variables the same.
  2. Count how many swings take place in 30 seconds while the students count the swings (to and fro equals one swing).
  3. Record results. Repeat 3 times for more valid reading.

Data Table:

Trial / Number of Swings
90 degree Angle / Number of Swings
45 degree Angle
1
2
3
Mean

Graph:

Make a bar graph of your data. What predicitions can you make from the data? What does the data tell you?

Conclusion:

What is the affect of changing the angle of release on the pendulum?

Mass of the Pendulum

Predicition:

How do you think changing the mass of the pendulum will affect the number of swings the pendulum makes?

Experiment

1. Add one or more paperclips to the pendulum bob and count the number of swings in 30 seconds.

2. Remember to use standard release position.

3. List variables.

4. Record results.

5. Make a graph of results.

6. Analyze.

7. Write conclusions.

Variables:

IV-

DV-

Results:

Conclusion:

Length of the Pendulum

Prediction:

How do you think changing the length of the pendulum will affect the number of swings the pendulum makes?

Experiment

1. Each group takes assigned swinger (All teams have different lengths) and counts swings released parallel to floor for 30 seconds.

2. List variables.

3. Record results.

4. Graph results on Foss Variable two-coordinate graph.

5. Analyze.

6. Write conclusions.

7. Place swinger on concrete graph.

IV

DV

Results

Conclusion

Using Graphs to Make Predictions

Purpose: To determine how graphs can be used to make predictions.

Procedure:

1. Complete a two-coordinate graph using data from the length of the pendulum lab.

2. Identify the x-axis and y-axis.

3. Graph your data by making a dot where the length of the swinger and the number of swings intersects. (where lines meet going across and up).

4. Connect the dots with a line using your ruler.

Stop and Think!

Does the type of data affect the type of graph we would use? Why? Give one example.

Results:

Can you predict how many swings an 80cm pendulum will make in 15 seconds? ______

Show me! 80cm=______swings in 15 seconds. How did you get your answer?