Arif Zaman 9/12/00 Hon. Matter/Energy Pd. 8 A Swinging Time Purpose: To determine the factor (s) that affect the period of a pendulum. Hypothesis: The factors that I think will affect the period of the pendulum are the displacement and the suspended mass because if the mass of the bob is a lot than it will take more force for the pendulum to swing and if there s a high displacement it will give the pendulum more energy to complete the cycle.

Materials: stopwatch 100, 200, and a 500 g bob protractor meter stick string Procedures: 1. Gather materials. 2. Start the string at a length of 130 cm. (control) 3. Attach a 200 g bob (control) to the bottom of the string.

4. Make the displacement 30 cm by pulling the bob 30 cm away from the center. Do this with a meter stick. 5. Let go of the bob and allow one full cycle before starting the stop watch. 6.

Stop the stop watch after the bob returns. 7. Record data. 8. Repeat steps 1-7 with a displacement of 60 cm. Then try a displacement of 90 cm.

9. Now repeat steps 1-7 with a length of suspension of 130 cm, 170 cm, and 210 cm. The controls are a bob of 200 g and a displacement of 90 cm. 10. Finally repeat steps 1-7 with 100 g, 200 g, and a 500 g bob. The controls are a displacement of 90 cm and a suspension of 130 cm.

Observations: controls-length of suspension 130 cm, bob 200 g How Displacement Affects the Period of a Pendulum Displacement Period 30 cm 2. 72 seconds 60 cm 2. 37 seconds 90 cm 2. 34 seconds controls- displacement 90 cm, bob 200 g How Length of Suspension Affects the Period of a Pendulum Length of Suspension Period 130 cm 2. 34 seconds 170 cm 2. 55 seconds 210 cm 2.

87 seconds controls- displacement 90 cm, length of suspension 130 cm How the Bob Affects the Period o a Pendulum Bobs Period 100 g 2. 29 seconds 200 g 2. 34 seconds 500 g 2. 69 seconds Conclusion: The purpose of this experiment was to determine the factor (s) that affect the period of a pendulum. The independent variables were the length of suspension, displacement, and mass (bob). The dependent variable was the period of the pendulum.

My hypothesis was that the suspended mass and the displacement would affect the period of the pendulum. My hypothesis was partially correct. I learned that the length of suspension also affects the period of a pendulum. The lower the length of suspension is the lower the time for a pendulum to complete a cycle. Connections/Textbook Research: 1. independent variable- The variable that s regulated by the scientist.

The independent variable can be chosen before conducting the experiment. e. g. time. dependent variable- The variable that changes as a result of the independent variable. This is the unknown factor and the reason for doing the investigation.

The values of the dependent variable are determined only after the experiment has been conducted. e. g. speed. Source- Reference 5 H. M and E Graphing techniques.

2. In this experiment the independent variables were the length of suspension, displacement, and the mass (bob) because they were the variables we could change. The dependent variable was the period of the pendulum because that was what we were measuring. 3. It s important to test one independent variable at a time because if you test more than one at a time there will be no control and you won t know which variable affected the experiment. 4.

The term control means An experiment ran without a variable (s) in order to show that any data from the experimental setup was due only to the variable that was being tested. This is a controlled experiment because we always kept two variables the same. Source- Exploring Physical Science, 1997, page 13. 5. qualitative observation- the observations of the characteristics of something. quantitative observation- the observation of the magnitude, size, extent, or amount of something.

Source- web 6. A hypothesis is a proposed solution to a scientific problem. A theory is a logical, time-tested explanation for events that occur in the natural world. The two are similar, however, a hypothesis is your or the answer to the problem. A law is a summarized statement of observed experimental facts that has been tested many times and is generally accepted true. A law was once a theory but was proven correct after many trials.

I think that this was a quantitative lab because we were observing measurements of time, length, and mass. Source- Exploring Physical Science, 1997, pages 8-9 and 12-14. 318.