Using a Pendulum to Find Gravity
Aim:
To find the gravity by finding the period of the oscillations of a
pendulum and plotting a graph.
Hypothesis and Prediction:
- the gravity from the graph is going to equal the gravity from the
formula.
Variables:
The independent variable is the length of the string
The Dependent variable is the period of one oscillation
Controlled variables are: - mass of the pendulum
Equipment:
-Brass Ball
-string
-boss and clamp
-stopwatch
-2 metal blocks
-Meter Ruler
-Micrometer
[IMAGE]
-The diameter of the brass ball was measured using a micrometer. Then
the value was divided by 2 to give the radius
-the length of the string was measured
-two metal block were clamped with the string in between, the string
was tied to the bob
-the bob was pulled to the side and released
-the time was started when the bob passed the reference line.
-a full oscillation is when the bob passes the reference line forth
back and forth again.
- the length of the string is increased or decreased in a regular
pattern
- the time was monitored by reading through the stopwatch.
-the same brass ball was used over the experiment to keep the mass
constant.
- the length was varied 10 times with a 10 cm difference.
-4 readings were taken for each 10 cm
-the time was taken for 20 oscillations. And then divided by 20 to
give one oscillation.
Data Collection:
Table number
Length of String / M
± 0.05
Number of oscillations
Time Taken/s
± 0.5
Period/s
± 0.5
1
1.01
20
39.65
1.9825
20
41.93
2.0965
20
39.82
1.991
20
39.94
1.997
2
Results: The experiments required the starting, ending, and total times of each run number. To keep the units for time similar, seconds were used. An example of how to convert minutes to seconds is: 2 "minutes" x "60 seconds" /"1 minute" ="120" "seconds" (+ number of seconds past the minute mark)
On the container, the researchers wrote down their first initial, last name and lab section. The researchers then poured spring water into the cylindrical container about halfway and then set it aside. Next, the researchers transferred the Planarian using a small plastic pipette into an empty petri dish filled with just enough water for the Planarian to swim around freely. After the successful transfer into the petri dish The researchers then measured how long the Planarian was using the unit millimeters.
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