Small variations in the acceleration due to gravity, g, occur at different places on Earth. This is because g varies with distance from the center of the Earth and is influenced by the subsurface geology. In addition, g varies with latitude due to Earth’s rotation. In this activity, you will be using a spark timer to collect free-fall data and use it to determine the acceleration due to gravity, g.
II. Materials and Procedure
* Spark timer
* Timer tape
* 1-kg mass
* Stack of newspapers
* Masking tape
1. Attach the spark timer to the edge of the lab table with the C-clamp. 2. If the timer needs to be calibrated, follow your teacher’s instructions or those provided with the timer. Determine the period of the timer and record it in your data table. 3. Place the stack of newspapers on the floor, directly below the timer so that the mass, when released, will not damage the floor. 4. Cut a piece of timer tape approximately 70 cm in length and slide it into the spark timer. 5. Attach the timer tape to the 1-kg mass with a small piece of masking tape. Hold the mass next to the spark timer, over the edge of the table so that it is above the newspaper stack. 6. Turn on the spark timer and release the mass.
7. Inspect the timer tape to make sure that there are dots marked on it and that there are no gaps in the dot sequence. If your timer tape is defective, repeat steps 4-6 with another piece of timer tape. 8. Have each member of your group perform the experiment and collect his or her own data. 9. Choose a dot near the beginning of the timer tape, a few centimeters from the point where the timer began to record dots, and label it 0. Label the dots after that 1, 2, 3, 4, 5, etc. until you get near the end where the mass is no longer in free fall. If the dots stop, or the distance between them begins to get...