Natural Science Unit 29 Laboratory Activity: Galilean Mechanics - The Pendulum
Goal: Measure the value of gravitational acceleration.
Materials and Equipment:
- Several masses; if you use coins, it is easy to double or triple your mass.
- Strong string or nylon fishing line, able to support your weight without breaking.
- Hook on which to tie pendulum; should be fastened to make the pendulum as long as possible (I used the ceiling hook for a hanging plant).
- Stopwatch or watch with second hand.
- Weigh your masses.
- Tie them to the end of the string.
- Tie the string to your hook.
- Measure as accurately as possible the distance between the hook and the center of the masses; this is your pendulum length L.
- Displace the pendulum (measure the horizontal distance x of the displacement of the pendulum from its rest position.)
- Find your pulse on your wrist.
- Count the number of pulse beats required for the pendulum to make 10 complete back-and-forth swings (10 periods). Record the number.
- Repeat at least twice, and average the number of pulse beats.
- Repeat your experiment, varying the mass. Does the number of pulse beats needed for 10 complete swings change?
- Repeat your experiment, varying the length of the string by at least 25%. Does the number of pulse beats required for 10 complete swings change?
- Repeat all your measurements, using a stopwatch to time the swings.
- Describe your experimental setup. Did you make any changes to the described procedure because of availability of equipment? Did you do anything to increase the accuracy of your measurements.
- Present your data and calculations in a useful tabular form. Clearly distinguish between measured values and calculated values. Give at least one example of each type of calculation you perform.
- Explain which factors (length of the string, mass of the weight, etc) affect the period of the pendulum and which do not.
- Was your pulse a good way to see the differences, or did you need the stopwatch?
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