Find out if the motion of an elastic band changes, by the rate of its extension.
Plan
Aim
The aim of my investigation is to find out if the motion of an elastic band changes, by the rate of its extension. So in other words if an elastic band is extended to 20cm, will it fire a greater distance, than a band which is extended to 10cm, and if so why?
Research
You can change the shape of a material by applying enough force. When you stop applying the force, some materials retain their new shapes; these are plastic materials. Other materials return to their old shape when you stop applying the force; these are elastic materials.
Elasticity is the ability to return to their original shape after being stretched, for example: an elastic or rubber band.
When you pull an elastic material, it stretches and increases in length. At first, when you double the pull, you double the increase in length. However, as the pull increases, you reach a point where the material no longer returns to its original shape. This pull is the elastic limit of the material.
Energy transfer
Energy is the capacity to do work. There are ten types of energy transfer each of which are explained below. Most types of energy are ultimately derived from the sun, or from radioactivity. All types of energy are measured in joules (J).
* Electrical energy = whenever a current flows.
* Light energy = From the sun, bulbs etc.
* Sound energy = Energy that has sound or noise coming from it, for example: loudspeakers.
* Kinetic energy = Energy of motion. Includes heat, sound and light (motion of molecules)
* Thermal energy = flows from hot objects to colder ones.
* Gravitational potential energy = Potential energy due to elevated position. Possessed by anything that can fall.
* Elastic potential energy = Potential energy due to tension-either stretch, for example: rubber bands etc. or compression, for example: springs etc.
* Chemical energy = Possessed by foods, fuels, and batteries.
The principle of the Conservation of Energy is:
Hypothesis
I predict that as the length of the extension increases, so will the distance travelled by the elastic band. This is because the further the extension, the greater the force there is within the band that is able to push against the resistance of the air easily.
While the band is being extended, it holds a lot of stored energy within it, otherwise known as potential energy. As the band is released this potential energy is transferred into motion energy, known as kinetic energy, which is the transferred gravitation potential energy, while the band is moving through the air and against the gravitation forces acting upon it.
So therefore all kinetic energy produced will convert in to gravitational potential energy as the band is released. Also as the graph states the bigger the extension, the more force is held within the band, therefore the more potential energy it will hold that can be converted to a larger amount of kinetic energy and a larger result of gravitational potential energy.
Variables
In order for my results to be valid, the experiment must be a fair one.
* I will keep the height of the meter stick off the floor the same.
* I will use the same elastic band for each recording
* I might not have enough time in one lesson to collect all the results needed. Therefore, I will leave the meter stick taped to the chair, and place it in a secure cupboard where it cannot be tampered with. Hence the meter stick is in the exact same ...
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Variables
In order for my results to be valid, the experiment must be a fair one.
* I will keep the height of the meter stick off the floor the same.
* I will use the same elastic band for each recording
* I might not have enough time in one lesson to collect all the results needed. Therefore, I will leave the meter stick taped to the chair, and place it in a secure cupboard where it cannot be tampered with. Hence the meter stick is in the exact same position as previously when I come to use it again the next day in my lesson.
Equipment/Apparatus:
Below is a list of apparatus I will use during my preliminary series of experiments. If everything goes accurately and correctly then I will use this list of apparatus for my real experiment.
Elastic band
Meter stick
Measuring tape
Laboratory chair
Preliminary Experiment
In order to obtain the best results possible, we carried out some preliminary
work in order to identify appropriate ranges and values, to be used in the final experiment.
The 1st stage of my preliminary work was to find a suitable type of elastic band to use within the experiment. Ideally we needed a band that would be able to be extended easily, and that when would land, would not move any further forward, so that a reading can be obtained easily and to the best accuracy. I collected a number of different sizes and width elastic bands and catapulted them off the end of a meter rule along a corridor. I chose from a choice of a:
* Short, thin elastic band
* A short thick, elastic band
* A long thin elastic band
* Along thick elastic band.
We immediately ruled out using the short thin elastic band, as it was:
(a) Too hard to extend, which would mean it would be difficult to extend to various lengths. Therefore, I wouldn't be able to get a varied range of readings.
(b) Because when the elastic band was released of the end of the meter rule, it travelled much too quick and high, and not straight enough, in that I couldn't determine an accurate reading. The elastic contained too much tension within it while it's being extended.
We had slightly the same problem with the short thick elastic band. However, we found that the best elastic band was the long, thick elastic band, because it's heavier. Therefore it's going to move through the air at a slower speed against the resistance, and will not move any further when contact is on the ground due to its weight. It also travelled more or less straight so that I could obtain a suitable reading. It's also easier to extend to the length required. So I believe that this band will provide us with the most accurate, varied range of results.
The next stage was to identify the range of units to which the band will be extended. I worked from the length of the elastic band of 0.09 m where it was too big to get any tension in order for it to go anywhere. I went up to 0.18 m where any further would snap the elastic band. In the end, I decided to use the following measurements, from 0.12 m to 0.18 m increasing every three cm. Therefore I used the following:
* 0.12
* 0.15
* 0.18
I decided to repeat each extension ten times over in order to establish a reasonable average result for each unit the band is extended, and to produce a good plotting point for each result on my graph, in order to be able to distinguish a pattern within my readings.
Method
To answer the questions in my aim, I plan to carry out an investigation, in which I will catapult an elastic band in to the air, which will be extended from various extensions. I will then proceed to measure the distance travelled by each new extension of the elastic band, using a meter rule, and from my result determine certain trends from the graph to answer the questions asked in my aim.
The length at which the elastic band will be extended to, will start from an extension of 0.12m, and will continue all the way up to 0.18m. A tape measure (total length of 7.0m) will be cello taped to the floor so that when the elastic band is catapulted, the distance travelled by the band can be measured accurately. The elastic band will be catapulted off the end of a meter stick, 0.78 m off the floor in front of the tape measure, which is taped to the floor. The band will be flung off the end of a meter stick, because the extension of the band can be measured easily using the units along the side of the meter rule.
To obtain the best and most accurate reading as possible, I had someone sit on a small stool so that it did not move from its original position. Each extension will be repeated ten times, in order to give an average distance for each extension made to the band.
When the data had been collected, I recorded my results onto a table (see overleaf).
Risk assessment
* ''Take care with where you put the meter sticks and make sure that they are secure, so that they don't fall over and hit someone or something -Awareness!''
* We also took precaution in that we wore safety goggles while the band was being catapulted, to prevent any injury to the eye.
During my preliminary experiments, I worked out all the exact pieces of equipment I need and will use. Therefore, below is a list of apparatus, which I will use
for the real experiment:
Elastic band
Meter stick
Measuring tape
Laboratory chair
Diagram
Below is a diagram of how I will set up my equipment for my experiment:
Sources used
To aid me with the planning, I used the following:
* Teachers lessons
* Key science-physics-by Jim Breithaupt
* Previous knowledge
Obtaining, analysing and considering Evidence
I have concluded my experiment and everything worked out to plan, and now that I have finished, below, is a list of my results, which I have gathered from completing it.
A table to show the results of how far an elastic band travels when extended to 0.12m
Length from which the elastic band is extended to (m)
Attempt numbers (1,2,3 etc.)
Distance between ruler and the floor (m)
Distance travelled (m)
Distance travelled from a different group (m)
0.12
0.78
3.60
3.63
0.12
2
0.78
4.55
4.18
0.12
3
0.78
3.91
3.06
0.12
4
0.78
4.13
3.16
0.12
5
0.78
3.60
4.02
0.12
6
0.78
3.45
2.98
0.12
7
0.78
4.10
3.57
0.12
8
0.78
3.00
3.55
0.12
9
0.78
2.59
3.12
0.12
0
0.78
3.60
3.67
Average distance travelled (m)
3.65
3.49
A table to show the results of how far an elastic band travels when extended to 0.12m
Length from which the elastic band is extended to (m)
Attempt numbers (1,2,3 etc.)
Distance between ruler and the floor (m)
Distance travelled (m)
Distance travelled from a different group (m)
0.15
0.78
5.21
4.52
0.15
2
0.78
4.90
4.62
0.15
3
0.78
4.43
5.23
0.15
4
0.78
4.60
4.45
0.15
5
0.78
4.32
4.97
0.15
6
0.78
5.26
4.73
0.15
7
0.78
4.48
4.34
0.15
8
0.78
5.21
4.60
0.15
9
0.78
4.53
5.12
0.15
0
0.78
4.60
4.48
Average distance travelled (m)
4.75
4.70
Length from which the elastic band is extended to (m)
Attempt numbers (1,2,3 etc.)
Distance between ruler and the floor (m)
Distance travelled (m)
Distance travelled from a different group (m)
0.18
0.78
4.85
5.85
0.18
2
0.78
4.83
6.63
0.18
3
0.78
5.29
5.39
0.18
4
0.78
5.55
5.73
0.18
5
0.78
5.84
4.62
0.18
6
0.78
6.0
4.98
0.18
7
0.78
5.37
5.48
0.18
8
0.78
4.26
5.06
0.18
9
0.78
6.36
5.92
0.18
0
0.78
5.58
4.79
Average distance travelled (m)
5.39
5.44
Overleaf are a number of graphs to represent the average results that I had collected and calculated from the experiment. (Graph 1).
As well as graph 1, I have included another graph (graph 2) in order to see my results in relation to different results that have been collected from another group. They are colour coded (other group = dark red...my group = blue).
Analysis and conclusion:
As one can see from the graphs, the longer the elastic band, the further it travelled. This is because as the elastic band extended beyond its natural length, by being pulled by force, tension was created in the band. Therefore, the more tension there was in the band, the further it would travel.
My prediction turned out to be exactly what I had expected. I predicted that as the length of the extension increases, so will the distance travelled by the elastic band. This is because the further the extension, the greater the force there is within the band that is able to push against the resistance of the air easily. This is because there is more potential energy in the band that can be converted to a larger amount of kinetic energy and a larger result of gravitational potential energy.
My graph should have looked like the following which it did meaning that all my results were correct.
Evaluation
Overall, I think that the results were very reliable as they turned out to be just what had been expected. The data that was recorded did not include any anomalous results and from this I can conclude that the technique used was consistent and reliable.
When referring back to my hypothesis, it is clear that the data collected is in accordance with what I had originally predicted.
When looking at the graph the points are arranged in such a position that a line may be drawn to connect them together. Due to there being a definite relationship between the points, it is possible to draw information from it. On the graph, there is a positive increase and correlation, which can be seen. At first, the increase is quite a steep one but then it gradually slopes off to a shallower gradient.
However, I don't think I collected enough evidence, but it was as accurate as it could have been in relation to the results, and there was enough evidence to support my conclusion.
As a whole, I think that the experiment worked out extremely well. However, one way which I could have used to improve my investigation is to have repeated the experiment another time. Therefore, I would get another average to add to my graphs to help support the rest of my conclusions. Another technique I could have used to improve my investigation would be data logging. This would have made collecting my results and recording them much easier.
I would have liked to extend my investigation. One way in which I could have done this is to measure the peak height at which the band reached each time it was travelling through the air. I also would have liked to measure the force, which was acting on the rubber band to see how that affected the distance travelled.
This would have been very enjoyable. However, I did not have enough time and there was also a lack of equipment which I would have needed.
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