Does the length of a pendulums string affect its swing time?
Grade 5
Presentation
Hypothesis
My hypothesis is that as I increase the length of the string of the pendulum ,the time period for one swing will decrease. I think so because according to me amplitude is affected so is the wave frequency it means when the waves are affected so is the swing time.
Research
A pendulum is a device which is used to measure time.It is basically a wire connected to metal or other material this bottom part is known as the bob.The bob swings back and forth.Pendulums follow the laws of newton.The swing rate or frequency on a pendulum is affected by its length from the point it pivots from.The motion of a pendulum is affected by two energies kinetic energy which acts when weight is moving and gravitational energy when its bob is in circular motion .How much you pull is how much it will move,so the amplitude is affected.When all factors are same like pendulum pivoting at one point and like it moving freely with gravitational force,the pendulum swing time will be affected so is the amplitude, wave frequency are affected.It follows the first law of newton,
SCIENTIFIC TERMS:
OSCILLATION:Oscillation is the process of moving back and forth regularly.
THE FIRST LAW of MOTION: An object at rest remains at rest, or if in motion, remains in motion at a constant velocity unless acted on by a net external force.
PENDULUM-A pendulum is a body suspend from fixed point so that it can swing back and forth under the influence of gravity.
GRAVITATIONAL FORCE- gravitational force is force of attraction between all masses in the universe.
WAVE FREQUENCY- wave frequency is the number of waves that pass a point in a certian period of time.
AMPLITUDE-amplitude is maximum disbalance or distance moved by a point on vibration
LAWS OF NEWTON-laws of newton mean motion related to any objects in motion to the forces acting on it.
GEAR SYSTEM-gear system consists of several gears and are major components of many engineered appliances.
BOB-A bob is a heavy object also called a weight or mass on end of pendulum.
KENETIC ENERGY:Kinetic energy is the energy an object has because of its motion.
POTENTIAL ENERGY:Potential energy is the stored energy in an object due to its position, properties, and forces acting on it
EQUILIBRIUM POSITION:The equilibrium position of a mechanical system is the position where the total force acting on it is zero.
DIAGRAM OF SIMPLE PENDULUM
Variables
RESPONDING 1.Time measured for one swing. |
CONSTANT 1.Number of swings. 2. Same time measuring device. 3.type of string . 4.Type of measuring tape. |
MANIPULATED 1.the length of the string on all pendulums. |
Procedure
1.Gather all materials
2.Make four pendulums with string lengths(0.25m,0.38m,0.51m,0.63m) .
3.First I hang the pendulum with length (0.25m) on a still object.
4.measure the degrees.Pull it up to 145 degrees
5.let it go from one extreme position to another through mean position and come back to the first extreme position (at 145 degree).
6.record time taken for one swing.
7.repeat the same with pendulum having string length(0.38m).
8.I hang pendulum with length(0.38m) on a still object.
9.measure degrees.pull the pendulum up to 145 degree.
10.let it go from one extreme position to another through mean position and come back to the first extreme position (at 145 degree).
11.record time taken for one swing.
12.repeat above steps two more times with pendulums of length (0.51m,0.63m).
13.find the average time period.
14.0.25m=0.96+1.00+1.28=3.24/3=1.08..0.38m=1.51+1.20+1.60=4.31/3=1.43.
15.Repeat experiment two more times for accuracy.
Observations
TIME PERIOD VS LENGTH OF A PENDULUM |
||||
LENGTH OF PENDULUM |
TRIAL 1 |
TRAIL2 |
TRAIL 3 |
AVERAGE |
10 inch(0.25m) |
0s 96ms |
1s 0ms |
1s 28ms |
1.08s |
15 inch(0.38m) |
1s 51ms |
1s 20ms |
1s 60ms |
1.43s |
20 inch(0.51m) |
1s 81ms |
1s 75ms |
1s 81ms |
1.79s |
25inch(0.635) |
1s 90ms |
1s 98ms |
2s 55ms |
2.14s |
Analysis
I am testing how does length of a pendulum affects its time period? FOR TRAIL 1.Pendulum with length of(0.25m,0.38m,0.51m,0.63m) had a time period of (0.16s,1.51s,1.81s,1.90s) respectively (increases). FOR TRAIL 2.Pendulum with length of (0.25m,0.38m,0.51m,0.63m) had a time period of (1.0s,1.20s,1.75s,1.98s) respectively increases.FOR TRAIL 3.Pendulum with length of(0.25m,0.38m,0.51m,0.63m) had a time period of (1.28s,1.60s,1.81s,2.55s) respectively (increases). Pendulum with a length of (0.25m,0.38m,0.51m,0.63m) had a average time period of (1.08s,1.43s,1.79s,2.14s) respectively (increases).The data shows as the length of the pendulum string increases so does the time period for one swing increases.This means that the length of pendulum is directly proportional to its time period.
Conclusion
Yes, the length of the pendulum affects its swing time.In my experiment as I increased the length of the pendulum swing so did the swing time increased.It means the length of a pendulum is directly proportional to its time period.
My hypothesis was incorrect because as I increase the length of pendulum string the time period increases.The length of a pendulum is directly proportional to its time period.
Application
I think people should care about the work I did because the information i provided can be used to study the laws of newton more.The new science learned by my project is that how the time period would increase as the length of pendulum string would increase? This would help us in everyday life because if we want to find the length of a pendulum whose time period is one second we would not have to make gear systems that is complicated .One day if more research is done this statement can come true so I thought to do this question.
If I was going to do this experiment again I would change:
1.The material of sting because when I was conducting the experiment the string was slipping from its position.
2.I would change the bob because it was unstable at points so I would make it heavier.
Sources Of Error
1.I thought the bob would be stable but when I hanged it it was slanted.
2.the string was slipping from the object it was hanged on.
Citations
If I was going to do this experiment again I would change:
1.The material of sting because when I was conducting the experiment the string was slipping from its position.
2.I would change the bob because it was unstable at points so I would make it heavier.
Acknowledgement
my acknowledgements go to my parent as they helped me in formating my slides and to my teacher who gave advice to me.