Passage
Students investigated what affects the period of a pendulum, the time for one complete back-and-forth swing. A pendulum was made by hanging a small metal bob from a string attached to a fixed support. In each trial the students timed several swings and calculated the period in seconds (s).
Experiment 1: Holding the bob mass and the release angle constant, the students changed the length of the string and measured the period (Table 1).
| String length (cm) | Period (s) |
|---|
| 20 | 0.9 |
| 40 | 1.3 |
| 60 | 1.6 |
| 80 | 1.8 |
| 100 | 2.0 |
Experiment 2: Holding the string length at 60 cm and the release angle constant, the students changed the mass of the bob and measured the period (Table 2).
| Bob mass (g) | Period (s) |
|---|
| 50 | 1.6 |
| 100 | 1.6 |
| 150 | 1.6 |
| 200 | 1.6 |
Experiment 3: Holding the string length at 60 cm and the bob mass constant, the students changed the release angle, keeping it small, and measured the period (Table 3).
| Release angle (°) | Period (s) |
|---|
| 5 | 1.6 |
| 10 | 1.6 |
| 15 | 1.6 |
| 20 | 1.6 |
In every trial the pendulum swung freely from the same fixed support.
