controlled variables in bouncing ball experiment30 Apr controlled variables in bouncing ball experiment
The push which the ball receives from the floor at the moment of impact causes it to bounce up from the surface. Drop a ball from 1 foot off of the floor, slightly in front of a yardstick. Identifying variables is necessary before you can make a hypothesis. This experiment might have been improved if we had developed a method for more accurately measuring the tennis balls bounce height. This slope tells us how bouncy the ball is. The sum of the two, mechanical energy, stays the same ( is conserved.). Hence the final answer is: \(\text{Total distance} = 2 \cdot S_n = 2 \cdot 9.6 m= 19.2m\). Several meter sticks for measuring the height of the bouncing ball or drawing a larger meter stick. As the ball is accelerating due to gravity, at 9.81m/s2it is constantly getting faster and therefore the drag force gets bigger and bigger. Read books, magazines or ask professionals who might know in order to find out the factors that affect the movements of a dropped ball. Then when dropping the ball again eye level will be kept level with the blue tack thus avoiding parallax errors. With no net force, the acceleration = 0 and the ball falls at a constant velocity. Stages of bouncing ball example, Panagi - StudySmarter Originals, Motion graphs of a bouncing ball, Panagi - StudySmarter Originals. This help to greatly increase the accuracy of the experiment. Your bibliography must contain sources that are available to you (at your school or local library). Repeat this test from 2 ft, 3 ft, and 1/2 ft. Do this test for each ball and record data. As CR = h2/ h1it follows the gradient of the graph change in h2/ change in h1= CR. This will be a table tennis ball. The area of the triangle can be found using the formula below. Repeat your tests 9 more times and each time lower the release height for 6 inches. Our dependent variable was. Once the drag force equals the gravitational force all forces are equal and acceleration stops. WebThe independent variables in the experiment are the heights that the balls are dropped from, the surface that the ball bounces on, the type of ball used, ball is dropped vertically, and that when dropping a ball no force is applied. Grades: Preschool and K-2 Length of Lesson: Approximately 45 minutes Related Video: The Hawk Factor episode Learning Goals: In the bouncing ball example, external forces such as air resistance are assumed to be zero. The answer lies in how far the ball has dented inward due to its collision with the floor. Have all your study materials in one place. My hypothesis is based on my observation of balls that are not well inflated. This causes thermal energy to be given off. WebVariables: Height from which the ball is dropped Mass of the ball Material ball is made from External factors, i.e. The equipment necessary to generate these conditions was not available and as a result the results obtained were not one hundred percent accurate. Click Create Assignment to assign this modality to your LMS. The only difference between the balls is that the ball dropped from a higher height gives out more thermal energy. Air pressure will affect the balls fall slightly as the concentration of air particles per cubic meter varies with air pressure. Often, mathematical equations can be made from graphs. \(E_{pot} = E_{kin} \cdot m \cdot g \cdot h = \frac{1}{2} \cdot m \cdot v^2\). No, as the acceleration is not proportional to the displacement. = The distance between the bottom of the ball before it is dropped and the ground. Apparatus:Clamp stand, meter rule 2, table tennis ball, desk. As energy cannot be created or destroyed it follows that the energy must have come from the energy that the ball possesses. As in both cases the main form of energy is GPE it follows that the higher the ball is dropped from, the higher the ball will bounce. Dependent Variable: The Bounce (How height is the ball going to Bounce) because of the You are now ready to enter your data on a spread sheet and get to work. A thrown or batted ball may travel faster than the terminal speed, but it will experience a large drag force from the air which is greater than its weight. The acceleration on the ball is the acceleration of gravity, which acts downwards on the ball. It therefore hits more air particles each second and so the force of drag is bigger the faster the ball goes. What is the force that causes a ball to bounce? Also the facts that there were no anomalies and that all of the points were very close to the line of best fit show that the experiment was relatively accurate. \(v^2 = 2 \cdot g \cdot hv = \sqrt{2 \cdot 9.81 \frac{m}{s^2} \cdot 3 m} = 7.67 \frac{m}{s}\). Also the mass of the ball affects the chances of the ball reaching its terminal velocity. The CoR can be measured directly by velocity measurements but often it is handier to measure the height of rise of the ball after it bounces relative to the height that it fell. The only difference is that no experimental variables are changed. 1. Our lab group was able to determine the relationship between drop height and bounce height. During the preliminary experiment it was established that time was not an important factor that had to be taken into account when deciding how many different heights to drop the ball from and the interval between those heights. Several balls, medium-sized super balls, hollow rubber balls, solid rubber balls, tennis balls, golf balls, baseballs, and whatever other types of balls are available. tennis and baseball) includes the CoR test. We also noted after we finished the experiment that the student taking measurements sometimes stood above the height when taking the measurement and sometimes kneeled on the floor so they had a different angle on the meter stick, which may have affected the measurement. This was when the ball was falling in air. D (60%) For a dropped ball, the total mechanical energy is defined as the sum of its kinetic energy and its gravitational potential energy. where g is the gravitational acceleration (9.8 m/ sec 2 at the Earths surface), and where h is the height of the object, measured with respect to any convenient zero- level. Several new questions may have occurred to you while doing experiments. The last term is also known as the nth term of a geometric progression; n is the number of terms and a is the first term while Sn is the sum of the terms in the sequence as shown in the equation below. The ball rebounds to 72 percent of its previous height and continues to fall. List three. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. The format you use to write your bibliography may look like this: Are you ready for more advanced ball drop projects? You will then take your bounces and their respective time intervals to a spread sheet. The more particles per cubic meter, the more drag acting upon the ball. The ball has reached its terminal velocity and cannot fall any faster (unless dropped in a vacuum). h1and h2are from the bottom of the ball as it hits the floor to the bottom of the ball at the top of its arc after bouncing. These stages are continuously repeated and shown in the sequence below. Use a uniform surface to drop the ball onto. As the ball flattening upon impact with the floor is not visible as it happens so quickly it would be almost impossible to measure the size of the ball on impact with the floor. Variables are the factors that are changed, measured or controlled. Parallax error will be avoided by dropping the ball one time that will not be measured and placing a blob of blue tack onto the meter rule at the approximate height it bounced to. The ball did not appear to reach its terminal velocity which also supports my prediction. WebRamp and ball, controlled study lab report. By registering you get free access to our website and app (available on desktop AND mobile) which will help you to super-charge your learning process. The bounce of a dropped ball has a direct relation with the release height. To find out what affects the height to which a ball bounces. It will be vinyl tiling. Additional list of material can be extracted from the experiment section. Try to find more information from physics or mechanics books. The coefficient of restitution is the ratio of the final to the initial relative speed between two objects after they collide. GPE=Mass (kg) Gravitational Field Strength (N/Kg) Height (m). The push that the ball receives from the floor at the moment of the impact causes it to bounce upwards. A ball that is dropped in air however is subjected to air resistance which affects the height to which it bounces. This will be repeated five times, possibly more (for accuracy), for each height and the top and bottom results will be discounted. However, they only stretch for an instant before atomic interaction forces them back into their original, tangled shape and the ball shoots upward. In this project we will try to find out what factors affect the bounce of a dropped ball. Design an experiment to test each hypothesis. The weight and material of the ball will be kept the same throughout the experiment by using the same ball. Charged Particle in Uniform Electric Field, Electric Field Between Two Parallel Plates, Magnetic Field of a Current-Carrying Wire, Mechanical Energy in Simple Harmonic Motion, Galileo's Leaning Tower of Pisa Experiment, Electromagnetic Radiation and Quantum Phenomena, Centripetal Acceleration and Centripetal Force, Total Internal Reflection in Optical Fibre. It was more reliable to use the middle three results as it automatically discounted any anomalies; assuming two similar anomalies were recorded for one height, if they were then they both would be discounted. Prior to the sample task, students investigated investigated forms of energy and energy transfers and transformations. Data Table 2: Average Bounce Height at Each Height: Graph 1: Height of Ball drop versus Height of ball bounce: Our data indicates that the hypothesis was incorrect. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. What principle describes the bouncing motion of a ball? Is a bouncing ball an example of oscillatory motion? Hypothesis: Based on your gathered information, make an educated It is also good to calculate the coefficient of restitution of your ball using the formula CoR = v/v = sqrt(h/h). This is repeated three times at 5 different heights. = The distance between the bottom of the ball at the top of its arc after bouncing and the ground. Constants: the same person takes all of the measurements, the same materials are used in every trial. At the point of maximum height, the ball momentarily has zero velocity, and the direction of velocity is changing from positive to negative. Many questions are related. Review each step of the procedure to find sources of potential errors. They identify variables to be changed, measured and controlled. \(Area = \frac{1}{2} \cdot base \cdot length\), \(Area = 0.5 m \cdot 50 m \cdot 50 m = 1250 m^3\). I called School Time and my husband and son came with me for the tour. Make a step-by-step list of what you will do to answer each question. Hypothesis. ", " My husband and son came with me for the tour. The ball pushes on the floor and the floor pushes back on the ball, causing it to rebound. Because of these forces, both the ball and floor deform inward. In this experiment you will test the bounce of a dropped ball for different surface hardness. If the coefficient to restitution = 0.7, a ball dropping from h, in a vacuum would reach the height of 0.7 h, As velocity increases air resistance increases in proportion to the square of the velocity. These are parts of the experiment that you try to keep constant throughout an experiment so that they won't interfere with your test. Therefore the ball dropped from the higher height must give out more thermal energy in order to end up with the same amount of energy as the other ball. Keep track of where you got your information from. WebLearn how to identify types of variables in a simple experiment with bouncing balls. Research questions pose a question about the Thus a typical ball bounces to 60% of its original height because it stores and returns 60% of the energy it had before the bounce. It was difficult to accurately measure the height of the bounce. Hold the ball at 6 feet height and release it on a hard concrete surface. Find the total distance of travel until the ball hits the ground for the 8th time. 1. 70% is retained. The bounce of a dropped ball has a direct relation with the air pressure inside the ball. Dependent variable is the height that the ball bounces. Dependent Variable: The height of the bounce. For the lower heights the flight time of the ball was extremely short and again it was difficult to move ones head over the distance from h. Do a larger amount of results; 1cm, 2cm, 3cm, 4cm etc. Your assistant will record the bounce. Also the ball flattening upon impact doesnt have to be taken into account whereas if one was measuring from the top of the ball as it hits the floor to the top of the ball before dropping it or at the top of its arc after bouncing or the middle of the ball as it hits the ground to the middle of the ball before dropping it or the middle of the ball at the top of its bounce then the fact that the ball flattens momentarily on impact with the floor would have to be taken into account. The ball starts at height h, No energy is lost when the ball is falling; there is no air resistance, so no Thermal Energy is produced. (The upward direction was assumed to be positive in this example. This means that if a heavier ball is to be used then it will need to be dropped from higher to reach its terminal velocity. Hence, the only force acting on the ball is gravity. of the users don't pass the Bouncing Ball Example quiz! When the ball travels in the negative direction (downwards), the velocity can be assumed to be negative. This is because the experiment is a very short and simple one to carry out and if conducted efficiently can be completed easily within the time span allowed for collecting evidence. Perform this test in a Gym or anywhere else where you have a hard surface and an accessible wall. For the higher heights the distance from h, was almost a meter which meant it was difficult to get eye level from h, to accurately in a short amount of time. Stop procrastinating with our smart planner features. It shows that heights were recorded that exceeded the height that the ball would have reached had it been dropped in a vacuum. Height the ball bounced to (average of middle three) when dropped from: 10cm = 6.7 6.7 = 66% of 10 (to the nearest percent), 20cm = 14.0 14.0 = 70% of 20 (to the nearest percent), 30cm = 22.3 22.3 = 74% of 30 (to the nearest percent). This will mean that I will have to have the interval between the different heights from which the ball is dropped from less than 20cm, probably at 10cm. The results of our experiment show that this probably is not the case. Materials: -Carbon Paper -Goggles -Golf Balls Variables that may affect the bounce of a dropped ball are: You may study the effect of any of these variables on the bounce of a dropped ball. The first thing to check is how you are making your measurements. If you choose to study on the effect of air pressure inside the ball, your variables will be defined like this: Independent variable (also known as manipulated variable) is the balls air pressure. Set individual study goals and earn points reaching them. Either the coefficient to restitution that was worked out is incorrect, which would mean that the first three results are inaccurate or subsequent results were inaccurate. Therefore of the GPE that the ball possessed at the beginning some energy is given off as thermal energy. Research questions therefore always refer to two variables, and the relationship between them. An investigation of the factors that influence the bounce height of a tennis ball when dropped onto the floor could consider the drop height and the type of surface the ball is dropped onto. The investigation could try to answer these research questions: WebBouncing balls. The more energy that the ball possessed before being dropped, the more energy was converted into KE while the ball fell. The higher the ball goes, the more GPE it ends up with. Upload unlimited documents and save them online. A geometric sequence is a progression where each term is related to the previous term, and it is related to the previous term by a number r, which is known as the common ratio of the sequence. This experiment would provide me with more results that are relevant to the experiment that I have already conducted. Controlled variables are air temperature, air flow, air pressure where you perform your tests. Figure 1. The following is a college level project, but some grade 9 to 12 students can also complete this with no problem. When the ball was dropped from the higher heights the ball began to show signs of reaching its terminal velocity before it reaches the ground. Hypothesis: If a tennis ball is dropped from a specific height then the ball will bounce to the same height. Dropping a ball from different heights Dropping a ball from different heights could affect This is Newtons Third Law of Motion- for every action there is an equal and opposite reaction. The control variable is not part of an experiment itselfit is neither the independent nor dependent variable but it is important because it can have an effect on the results. The experiment was conducted well however as the utmost efforts were brought into place to avoid parallax error and it was ensured as far as possible that factors that affected how high the ball bounced, excluding the height, were kept constant throughout the experiment. where m is the mass of the moving object, and v is the velocity of the moving object. Is your hypothesis correct? If the elastic potential energy is the same then the same amount of energy is converted back into KE and so the balls leave the floor at the same speed. No, the bouncing ball example is not an example of simple harmonic motion. However if two results are recorded that do not fit the trend of other results nor are close to results recorded for that height then the experiments accuracy would be brought into doubt. Additionally we were able to practice reading a lab, taking data and making a graph. A control is a neutral reference point for comparison that allows you to see what changing a variable does by comparing it to not changing anything. This applies to a ball falling in a vacuum. What is the control variable in the bouncing ball experiment? Studying tables and graphs, we can see trends that tell us how different variables cause our observations. The ball has reached its terminal velocity and cannot fall any faster (unless dropped in a vacuum). These stages can also be represented graphically using three plots including a displacement, velocity, and acceleration vs time graph. What type of motion does a bouncing ball experience? This project guide contains information that you need in order to start your project. Gravitational potential energy means energy that an object has based on where it is located in a gravitational field. For this reason, its also known as a controlled variable or a constant variable. If you are author or own the copyright of this book, please report to us by using this DMCA report form. You may need to calculate the average of bounce height. This would eliminate parallax error further. Controlled variables are air temperature, air flow, air pressure where you perform your tests. As gravity remains the same the amount of work acting on the ball remains the same (apart from slightly more air resistance due to the ball travelling faster and so hitting more air particles per second, but the effect of this is negligible) and the ball travels further before stopping. As there is more GPE more energy is converted into KE (The ball is going faster, KE=1/2mv. This is because it is the easiest and quickest variable to alter. We have a new and improved In my science fair experiment, the golf ball overall was the ball that bounced the highest. The formula for gravitational potential energy is PE = mgh where m is the mass of the ball measured in kg, g is the gravitational acceleration constant of 9.8 m/se c2 , and h is the height of the ball in m. As the ball falls through the air, the potential energy changes to kinetic energy. This is because as the ball goes faster it passes through a greater volume of air each second. For instance, air resistance would slow down the tennis ball much more when it is dropped from 100 m than when dropped from 1 m. This difference in impact speed would probably affect the bounce height. All of the factors that could have affected the results that were uncontrollable could have produced variations between results. The third stage is the point at which the ball is momentarily deformed, and bounces off the ground in an upward direction until it reaches its maximum height. Test your knowledge with gamified quizzes. Improvements that could be made to the experiment if future work was to be done: To provide additional relevant evidence I would conduct further work as follows; I would like to conduct the same experiment in a vacuum. It tells us that the ball consistently bounced to half of its drop height. Air resistance exists but does not affect the velocity of the ball significantly. WebDrop the ball from the line between cinder blocks/bricks to make the measurements more accurate. If you choose to study on any other variable, following are samples of hypothesis. Specifically, you are tasked to determine: B.) A control is the variable that is not changed in the experiment. The purpose of our lab was fulfilled. WebControlled Variables: Bouncy ball used, surface bounced off of, technique in which ball was dropped (initial height was measured from base of ball). This produces a different amount of response in the system. Something about its situation then must determine its rebound, but what? However, the tennis ball we used may be a very old one, and to definitely prove that our hypothesis is wrong for most tennis balls we would need to repeat the experiment with many different tennis balls. Bounce/Release is the relation of bounce height to the release height. On a molecular level, the rubber is made from long chains of polymers. These conclusions help us confirm or deny our original hypothesis. Using the graph above, we can find the displacement by using the area under the graph, which is equal to the displacement. The Particular experiment is about : How does the drop height of a ball affects the bounce height of the ball. When raw data gets processed mathematically, for example, it becomes results. Drag is a squared function of velocity and therefore as the ball drops drag increases a greater amount each second. If you are using windows sound recorder program, you can view the recorded waves with an accuracy of 0.01 second. Instead, as the ball is still always loosing GPE so long as it is still falling, all GPE is converted into thermal energy. This is in accordance with Newton's second law. When the ball collides with the floor, the ball becomes deformed. The moving ball gains kinetic energy when it bounces, and loses potential energy as it falls. Constants are the release height, the bouncing surface, the type and the size of the ball. WebThe scientific method consists of five steps: -Observation/research: The first step is to research and collect as much background information on your chosen question as you can. Is a bouncing ball an example of simple harmonic motion? h2= The distance between the bottom of the ball at the top of its arc after bouncing and the ground. This is impossible. An increase in h1, assuming g and m stay constant, results in an increase in m g h1 which results in an increase in GPE. Therefore the ball ends up with more GPE, , assuming g and m stay constant, results in an increase in m g h, , assuming g and m stay constant, results in a decrease in m g h, As the ball is accelerating due to gravity, at 9.81m/s. You will be able to precisely measure the time intervals between bounces. WebControl variables include the size of pots, the type of soil and the position in a room. At the terminal speed, the drag force = the gravitational force. At 3ft, the basketball bounced 20 inches, the tennis ball bounced. Based on these trends, we can draw conclusions about the system under study. A totally accurate experiment would have a variation between results equal to zero however an experiment that is totally accurate needs to be conducted under conditions where air pressure and temperature remained constant, error produced by the ball falling on different parts of the linoleum floor tile (which was not totally even and thus produces inaccurate results) and human error removed by dropping the ball onto a uniform surface and using machinery to record the height to which the ball bounced to. The results of the experiment were obtained with a method that ensured that every drop was under similar conditions which ensured a fair test. The more KE the ball leaves the floor with the longer it takes to stop due to the force of gravity and return back to the floor again. If possible, have a scientist review the procedure with you. WebOn the cardboard, mark the starting point, the point where the marble strikes the wood, and a point along the marble's path as it rolls away from the wood. Experiment 2 is for testing the effect of air pressure. Calculating the coefficient to restitution of ball hitting the floor: The coefficient to restitution can be found out from a graph of h1against h2. will be from the bottom of the ball as it hits the floor to the bottom of the ball at the top of its arc after bouncing. Because the ball is softer than the floor, it does most of the denting and stores most of the energy. Also the difference between the force of air resistance acting upon a ball travelling at 1ms-1 and the force of air resistance acting upon a ball travelling at 2ms-1 is far smaller than the difference between the force of air resistance acting upon a ball travelling at 20ms-1 and the force of air resistance acting upon a ball travelling at 21ms-1. This therefore provides accurate and reliable results. it seems the ball is experiencing an oscillatory motion. Temperature will not affect the balls bounce either as the experiment will be conducted at room temperature, thus not allowing the floor to get cold and in doing so alter its affect upon the ball on impact. Sometimes variables are linked and work together to cause something. This coefficient of restitution, e, is actually the ratio of the velocity of recession (upwards after the bounce) to the velocity of approach (downward before the bounce). As the ball falls through the air, the Law of Conservation of Energy is in effect and states that energy is neither gained nor lost, only transferred from one form to another. It was difficult to get down to the exact level of the blue tack seeing as it meant lowering your entire upper body in the short amount of time taken for the ball to hit the floor and rebound again to get your eye level from h1 to h2 (where the blue tack was stuck, approximately). Therefore any change to the height from which the ball starts with affects the height to which it bounces to. Its 100% free. The first stage is where the ball bounces from the surface of the ground. Course of Theoretical Physics : Mechanics (Course of Theoretical Physics), Engineering Mechanics Dynamics (11th Edition). - Height at which the So once you know how to calculate KE and GPE, it is simple to calculate their sum, E. KE of a dropped ball changes as it falls. In this experiment you will measure the bounce of a dropped ball for different release heights. The procedure allowed me to observe the affects of the height from which a table tennis ball was dropped from upon the height to which it bounced. The formula for kinetic energy is KE=1/2 mv 2 , where m is the mass in kg and v is the velocity in m/sec 2 . This motion can be described using a geometric sequence, as the height of the ball after each bounce depends on the initial height from which the ball fell. Use a racquetball, a golf ball or any kind that bounces well and makes a nice crisp sound when it bounces. The balls finish up with the same amount of energy and the only energy given out is thermal energy. As the ball is falling toward the ground its Kinetic Energy is increasing because its speed is increasing. As the height from which the ball was dropped from was increased, the GPE energy that the ball possessed before being dropped also increased. Hence the formula for the sum of the infinite number of terms can be rewritten as seen here. Specially look for parts that discuss the gas pressure and physical properties of gases. The dependent variable is how high the ball bounces. Control variables include the type of ball, the surface that it is dropped onto and the size of the ball. 3. Testing reaction times can be investigated by dropping a ruler and seeing how quickly someone can grab it. The independent variable is the person who is trying to catch the ruler. These are illustrated below. This would mean that one could re-examine the height to which it bounced to and find it exactly instead of having to make a split second judgement which is not half as accurate. Conveniently enough, this fraction of returned energy is nearly independent of how much energy the ball had to begin with. Method: To set up the WebThis experiment,is an investigation into the maximum height of the bounce of a ping pong ball when it is first released.This is because of the unpredictability of the bounce not always reaching the same height.This we can assume their are many factors effecting the bounce of the ping pong ball.The following experiment will determine how different
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