Abstract
Do you know that a stream of water can ‘bend’ under the effect of static electricity? Straying from its original down-flowing path, the water would ‘bend’ towards a charged object placed near it.
This project is conducted to find out more about the strength of attraction between the stream of water and the charged object and the degree of ‘bend’ of the stream of water. This will be achieved by conducting a series of experiments and tests,
The conclusion is that the strength of attraction between the stream of water and the charged object does indeed affect the degree of ‘bend’ of the stream of water. Why though? This research paper brings a clearer idea of the process taken to find these answers and about the wonders behind this natural process.
Introduction
Water ‘bending’, a simple trick performed by magicians. Defying the laws of gravity, the stream of water would ‘bend’ away from its original path. It may seem like magic, but in reality, it is just simple science. With the help of static electricity, this is made possible.
The purpose of this experiment is to find out more about how the strength of attraction affects the degree of ‘bend’ of the stream of water
For starters, what exactly is static electricity? Many people might have heard about it or even generate static electricity in their daily life. Static electricity is the accumulation of electrical charges on the surface of a material, usually an insulator or bad conductor of electricity. It is given the name “static” due to the fact that there is no current flowing, compared to other types of electricity. (Ron Kurtus – succeed in understanding physics http://www.school-for-champions.com/science/static.htm ) The concept behind static electricity is similar to that of the magnet. Like charges repel while opposite charges attract.
Static electricity is developed and accumulated when two objects are rubbed against one another. When that happens, electrons jump from one object to the other. The object that loses electrons becomes positively charged while the object that loses electrons become negatively charged. In the case of this experiment, a balloon is used. The balloon is rubbed against the hair, causing the balloon to become negatively charged. When the charged balloon is placed near the stream of water, the negative charges of the balloon attract the positive charges present in the stream of water. This causes the stream of water to ‘bend‘ towards the balloon and away from its original path. This is all made possible because the atoms in the stream of water can move around freely, allowing the stream to bend towards the balloon. (Ron Kurtus – Succeed in understanding physics, http://www.school-for-champions.com/science/static_causes.htm)
Static electricity is formed much better when the air the humidity is low. When the air is humid, water molecules can collect on the surface of various materials. This can prevent the buildup of electrical charges.
It was also stated all charged objects create an electric force field that extends outward into the space that surrounds it. The charge alters that space, causing other object that enters the space to be affected by this field. The stream of water, under the influence of the electric force field, becomes charged, and thus, ‘bend’ towards the charged object, the balloon. (© 1996-2011 The Physics Classroom, http://www.physicsclassroom.com/class/estatics/u8l4b.cfm)
The main objective of this project is to find out, does the strength of attraction between the negative charges on the balloon and the positive charges in the stream of water affect the degree of ‘bend’ of the stream of water.
The hypothesis of the experiment is that the strength of attraction between the negative charges on the balloon and the positive charges in the stream of water does affect the degree of ‘bend’ of the stream of water. The whole experiment is separated into two sub-experiments, testing the two different factors that affect the strength of attraction: distance and charges.
In the case of the distance experiment, the hypothesis is that the closer the balloon is to the stream of water, the larger the degree of ‘bend’ of the water.
The dependent variable, the variable that is to be measured is the degree of ‘bend’ of the water. The Independent variable, the variable that is to be changed would be the Distance between the stream of water and the balloon.
In the case of the charges experiment, the hypothesis is that the higher the amount of charges on the balloon, the larger the degree of 'bend' of the water.
The dependent variable, the variable that is to be measured is the degree of ‘bend’ of the water. The independent variable, the variable that is to be changed would be the number of times the balloon is rubbed against hair.
Apparatus and Materials
- 1 metronome
- 3 Water faucets
- 1 Camera
- 14 balloons
- 1 balloon pump
- 1 scale
- 1 small distance scale
- Online screen protractor tool
- Hair
- 1 15cm-ruler
- 1 voltmeter
- 3 beakers
- 500ml water from kitchen tap
- 500ml water from Balcony tap
- 500ml water from shower tap
- 3 Crocodile clips
- 2 cooper sticks
Methodology
Step 1: Before beginning on the experiment, more extensive research needs to be done on the subject, such as the scientific explanation and theory behind static electricity.
Step 2: By using Google, search online for information relevant to the experiment.
Step 3: A suitable tap with water of higher voltage needs to be located to conduct the experiment. By briefly conducting a test, find out the voltage of the water from taps located at different locations. (Refer to Appendix A for the procedure)
Step 4: Conduct mini experiments before beginning the primary experiments to collect more data as not all information can be found on the internet, such as the effect of the voltage of water on the degree of ‘bend’ of water and the time taken for static electricity to disperse. (Refer to Appendix A for the procedures)
Step 5: Upload the videos taken on the mini experiments onto IMovie and edit the video.
Step 6: Download a free trial of the online protractor tool to help measure the angles. Take a screenshot after pausing the video at the largest ‘bend’ seen in the stream of water. Drag the protractor tool onto the screenshot picture to measure the angle of the ‘bend’. (Refer to appendix A for pictorial example)
Step 7: With the necessary information and data gathered from the mini experiments and the Internet, it is time to start the two primary experiments to prove my hypothesis.
Experiment: Distance
Research question: Does the distance between the stream of water and the balloon affect the degree of ”bend” of the water?
Hypothesis: The closer the balloon is to the stream of water, the larger the degree of ‘bend’ of the water.
Variables:
Dependent: Degree of ‘bend’ of the water
Independent: Distance between the stream of water and the balloon
Constant: Size of the stream of water, size of the balloon, amount of charges, material of the balloon, amount of air pumped into the balloon, speed of metronome, number of times balloon is rubbed against hair,
Experiment procedure:
1. Make a scale and place it behind the water faucet (Ensure that the stream of water is flowing straight along the line drawn on the scale)
2. Place a small distance scale on top of the tap to roughly estimate the distance
3. Use the balloon pump to pump up the balloon (about 10 pumps)
4. On the water faucet
5. Rub the balloon against your hair (about 50 times)
6. Use a metronome to ensure constant speed when rubbing (150 BPM)
7. Place the balloon near the faucet (about 1cm)
8. Take a video of the process
9. Repeat steps 3-8 at distance of 2cm and 3cm
10. Repeat the experiment again for another two times
11. Use the online protractor tool to measure the degree of the 'bend' in the stream of water
12. Tabulate the results for easy reference
Experiment: Charges
Research question: Does the amount of charges affect the degree of ‘bend’ of the water?
Hypothesis: The higher the amount of charges on the balloon, the larger the degree of 'bend' of the water.
Variables:
Dependent: Degree of 'bend' of water
Independent: number of times balloon is rubbed against hair
Constant: speed of metronome, Size of the stream of water, size of the balloon, material of the balloon, amount of air pumped into the balloon, distance between the balloon and the stream of water
Procedure:
1. Make a scale and place it behind the water faucet (Ensure that the stream of water is flowing straight along the line drawn on the scale)
2. Place a small distance scale on top of the tap to roughly estimate the distance
3. Use the balloon pump to pump up the balloon (about 10 pumps)
4. On the water faucet
5. Rub the balloon against the hair (about 25 times)
6. Use a metronome to ensure constant speed when rubbing (150 BPM)
7. Place the balloon near the faucet (about 1cm)
8. Take a video of the process
9. Repeat steps 3-8 again by rubbing the balloon against the hair for 50, 75 and 100 times respectively
10. Repeat the experiment again for another two times
11. Use the online protractor tool to measure the degree of the 'bend' in the stream of water
12. Tabulate the results for easy reference
Step 8: Repeat steps 5-6 to find the angles and collate the information.
Results:
Results
Degree of ‘bend’ of the water stream | ||||
Distance between balloon and the stream of water | 1st attempt | 2nd attempt | 3rd attempt | Average |
1cm | 5.79° | 5.11° | 3.05° | 4.65° |
2cm | 3.36° | 3.22° | 2.64° | 3.07° |
3cm | 2.87° | 1.74° | 0.79° | 1.80° |
Table 1 shows how the distance between the balloon and the stream of water affect the degree of ‘bend’ of the stream of water.
Figure 1 shows the difference in the degree of ‘bend’ of the stream of water when balloon is placed 1cm, 2cm and 3cm away from the stream of water respectively.
Degree of ‘bend’ of the stream of water | ||||
Number of charges | 1st attempt | 2nd attempt | 3rd attempt | Average |
25 times | 3.36° | 4.02° | 3.08° | 3.49° |
50 times | 5.79° | 5.11° | 3.05° | 4.65° |
75 times | 6.06° | 5.68° | 4.03° | 5.26° |
100 times | 7.05° | 6.69° | 8.10° | 7.28° |
Table 2 shows how the number of charges affects the degree of ‘bend’ of the stream of water
Figure 2 shows the difference in the degree of ‘bend’ when the balloon is rubbed 25 times, 50 times, 75 times and 100 times against hair respectively.
Discussion
Data analysis:
Distance experiment:
Original Hypothesis: The closer the balloon is to the stream of water, the larger the degree of ‘bend’ of water.
From the background research conducted, it is proven that water can indeed ‘bend’ under the influence of static electricity. However, there is no mention about whether or not the distance between the stream of water and the charged object will affect the degree of ‘bend’.
By collecting the data of the results, the hypothesis can be proven. Figure 1 in the results column above shows the average degree of ‘bend’ of the stream of water when the balloon is placed at three different distances away from the stream as a down-sloping graph. The stream of water ‘bends’ at an average angle of 4.65° the balloon is placed at a distance of 1cm away from it and at an average angle of 1.80° when placed at a distance of 3cm away from the stream. There is an obvious decrease in the degree of ‘bend’ when the balloon is placed at 1cm, 2cm and 3cm respectively. A simple interpretation of the graph would be that degree of ‘bend’ of the water increases when the distance between the stream of water and the balloon decreases, proving the hypothesis correct.
By relating it back to the main research question does the strength of attraction between the negative charges on the balloon and positive charges in the stream of water affect the degree of ‘bend’ of the stream of water, the results proved that distance, one of the variables affecting the strength of attraction, affects the degree of ‘bend’ of the stream of water, providing 50% of the evidence needed to prove the main hypothesis correct.
Charges experiment:
Original hypothesis: The higher the amount of charges on the balloon, the larger the degree of 'bend' of the water.
From the background research conducted, it is proven by the electric field concept that the charges affect the electric force field. All charged objects create an electric field that extends outward into the space that surrounds it. The charge alters that space, causing any other charged object that enters the space to be affected by this field. The strength of the electric field is dependent upon the amount of charges present in the charged object. The strength of the electric force field, in turn affects the degree of ‘bend’ of the stream of water. To prove this hypothesis, this experiment is conducted.
By collecting the data of the results, the hypothesis can be proven. From figure 2 in the results column, it shows the average of the degree of ‘bend’ of the stream of water when the balloon is rubbed against the hair for 4 different numbers of times as an up-sloping graph. The water ‘bends’ at an average angle of 3.49° when balloon is rubbed 25 times against the hair and at an average angle of 7.28° when balloon is rubbed 100 times against the hair. There is an obvious increase when balloon was rubbed against the hair for 25time, 50times, 75 times and 100 times respectively. A simple interpretation of the graph would be that as the amount of charges on the balloon increase, the degree of ‘bend’ of the water also increases, proving the hypothesis correct.
By relating it back to the main research question, this results prove that the amount of charges, the other variable affecting the strength of attraction, affects the degree of ‘bend’ of the stream of water, providing the other remaining 50% of evidence needed to prove the main hypothesis correct.
Assumption
Certain assumptions were made continuously throughout the experiment, such as the distance factor, the pressure factor and the humidity level.
The distance factor. Not every measurement can be accurate. Even with the distance scale, the distance between the balloon and the stream of water will not be accurate as the distance scale only serves in giving a brief estimation of the position of the balloon. The distance may be close to the desired number but the human eye cannot correctly estimate the exact distance. So, throughout the experiment, the distance between the balloon and the stream was assumed to be correct.
The pressure factor. The amount of static electricity on the balloon is also assumed to be the same. Since force also plays a role in the equation of the strength of the electric force field, in order to ensure that the experiment is conducted fairly, the force applied is assumed to be the same throughout. However, logically speaking, that is not possible. One may unconsciously increase the amount of pressure used when rubbing the balloon against the hair. It is nearly impossible for one to use the same amount of pressure continuously.
The humidity level is also assumed to be the same. Since the experiments are done on different days, the level of humidity on separate days may be different. However, due to time constraint, the two experiments could not be conducted into a day. Thus, the humidity level is assumed to be the same of the two days that the two experiments are done respectively.
Limitations:
There will be human errors present in the measurement, even with the help of measuring devices, so without a more advanced level of technology, it is not very possible to measure the correct length accurately.
It is not very possible to maintain the same amount of pressure as the amount of pressure always changes. This change may be so small that most of the time, it goes unnoticed. However, the change will affect the result of the experiment, as force is one of the factors that affect the electric force field created.
Not only that, the humidity level may also be different, since the experiments are not all conducted in one go. It may be more humid on certain days compared to others, thus, on certain days, the degree of ‘bend’ may be smaller than when conducted on other days.
Conclusions
The main aim of this experiment is to find out whether or not the strength of the attraction between the charges affects the degree of ‘bend’ of the stream of water. The main hypothesis is that the strength of attraction does indeed affect the degree of ‘bend’ of the stream of water.
From the distance sub-experiment conducted, the results prove that closer the smaller the distance between the stream of water and the balloon, the stronger the attraction between the negative charges on the balloon and the positive charges in the stream of water.
From the charges sub-experiment conducted, the results prove that the higher the amount of charges on the balloon, the stronger the attraction between the negative charges on the balloon and the positive charges in the stream of water.
With the two sets of results and data at hand, it can be safely concluded that the main hypothesis is correct.
Future plans
Extension:
Surface area
The experiment can be furthered extended by testing on other factors such as Surface area that comes in contact with the stream of water. According to the inverse square law equation, surface area is not taken to account in the equation and thus, should not affect the strength of the electric force field produced. By using that knowledge, another experiment can be conducted. Take the hypothesis, as surface area does not affect the degree of ‘bend’ of the stream of water. From the experiments above, it has been proven that the strength of the electric force field does affect the degree of ‘bend’ of the stream of water. This experiment can be conducted as an extension to test out the inverse square law since the hypothesis is based on it.
By using different types of balloons, the surface area that comes in contact with the stream of water changes. The experiment can be conducted using a round balloon and a long balloon. The independent variable in this case will be the shape of the balloon and the dependent variable the degree of ‘bend’ of the stream of water.
Different generators
Another extension can be done about the different generators of static electricity. Balloon and hair are not the only combinations around, other objects such as wool jacket or nylon comb can also generate static electricity. According to the tribo-electric series, hair, wool and nylon all become positive when charged. This experiment can be used to find out which of the three is able to generate the most static electricity? Due to the lack of information regarding this topic, the hypothesis being that balloon is able to create the greatest degree of ‘bend’ in the stream of water among the three, does not have a firm basis but is merely a guess. This experiment can be conducted to prove the hypothesis right or wrong.
The independent variable in this case is the generators of static electricity and the dependent variable is the degree of ‘bend’ of the stream of water.
References
1) Web Site
Electroscope, Internet: <http://www.school-for-champions.com/science/static_detection.htm>
2) Web Site
Electric force field intensity, Internet: <http://www.physicsclassroom.com/class/estatics/u8l4b.cfm
3) Web Site
Inverse Square law, Internet: <http://hyperphysics.phy-astr.gsu.edu/hbase/forces/isq.html
4) Web Site
5) Web site
6) Web Site
Static materials, Internet: <http://www.school-for-champions.com/science/static_materials.htm>
7) Web site, Variables that affect static electricity:
8) Web Site
