Its height gradually decreases until it eventually stops moving. Once the drag force equals the gravitational force all forces are equal and acceleration stops. 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. We have a new and improved Earn points, unlock badges and level up while studying. By the time the ball comes briefly to a stop, most of its missing energy has been stored in its dented surface. If the drag is less the ball will fall faster and is less likely to reach its terminal velocity. If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. This is in accordance with Newton's second law. Without a control you cannot be sure that changing the variable causes your observations. 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 It is also good to calculate the coefficient of restitution of your ball using the formula CoR = v/v = sqrt(h/h). You will need an assistant, so one person will drop the ball and the other person stands about 20 feet away and records how high it bounces. For instance result 3 from 200cm was an anomaly but was not taken into account when taking the average of the middle three. A control is the variable that is not changed in the experiment. The ball did not appear to reach its terminal velocity which also supports my prediction. This proves that the higher h1the more h2will differ from the height that the ball would have reached had it been dropped in a vacuum. 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. Controlled variables are air temperature, air flow, air pressure where you perform your tests. The higher the air pressure the more air particles per cubic meter. Hypothesis. A ball falls from 8 metres and rebounds to 52 percent of its previous height. Kinetic energy is energy of motion. Independent: - Type of surface the tennis ball is dropped on. In this experiment you will test the bounce of a dropped ball for different surface hardness. The more energy that the ball possessed before being dropped, the more energy was converted into KE while the ball fell. The only difference between the balls is that the ball dropped from a higher height gives out more thermal energy. The coefficient of restitution is the ratio of the final to the initial relative speed between two objects after they collide. A ball falls from a height of 6 metres. Since v2 = 2gh, the CoR = v/v = sqrt(h/h) where h is the height of the bounce and h is the height from which the ball is dropped. Hypothesis: If a tennis ball is dropped from a specific height then the ball will bounce to the same height. This is because it is easiest as the figure read of the meter rule is the result. Additionally we were able to practice reading a lab, taking data and making a graph. When the ball travels in the negative direction (downwards), the velocity can be assumed to be negative. WebControlled Variables: Bouncy ball used, surface bounced off of, technique in which ball was dropped (initial height was measured from base of ball). This was when the ball was falling in air. What principle describes the bouncing motion of a ball? It tells us that the ball consistently bounced to half of its drop height. The ball weighs exactly 2.5g. Controlled variables are air temperature, air flow, air pressure where you perform your tests. The three trials at each height are then averaged, and the average bounce height is graphed versus the drop height. Do you think e is constant for your ball? The average variation between results was 3cm. Instead, as the ball is still always loosing GPE so long as it is still falling, all GPE is converted into thermal energy. Does a ball bounce higher or lower in moon (Less Gravity), while all other conditions are constant? If you have any questions or need more support about this project, click on the , If you are new in doing science project, click on . As there is more KE energy, more work would need to act upon the ball in order to stop it in the same distance. These conclusions help us confirm or deny our original hypothesis. The results of the experiment were obtained with a method that ensured that every drop was under similar conditions which ensured a fair test. For a falling object the Coefficient to restitution (CR) is equal to the velocity squared as the object is travelling at as it leaves the floor (v22) divided by the velocity squared as it hits the floor (v12): If dropping a ball in a vacuum all you need to know in order to know how high the ball will bounce to is h1 and CR. Find out about the physics of a dropped ball. Stop procrastinating with our smart planner features. Now is the time to pull together what happened, and assess the experiments you did. The energy chain is as follows: Therefore as energy cannot be created or destroyed the energy the ball starts with must be directly proportional to the energy the ball finishes with, at the top of its bounce, and so if the ball starts with more energy it must therefore finish with more. It therefore hits more air particles each second and so the force of drag is bigger the faster the ball goes. 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. If the ball is elastic in nature, the ball will quickly return to its original form and spring up from the floor. Therefore the energy that the ball hits the floor with = mh, The proportion of energy lost when ball hits the floor = The Coefficient to the restitution of the two objects (C, All of the energy that the ball leaves the floor with is converted back into GPE, If dropping a ball in a vacuum all you need to know in order to know how high the ball will bounce to is h, can be found out by looking at a graph, the gradient, as a percentage of 1 gives the amount of energy conserved and therefore C. The clamp stand will be clamped down to the desk using a g-clamp to prevent it falling over and causing possible injuries. This list is called an experimental procedure. A) Find the total distance of travel until the ball hits the ground for the 5th time. This is Newtons Third Law of Motion- for every action there is an equal and opposite reaction. The weight and material of the ball will be kept the same throughout the experiment by using the same ball. 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. In a real-life scenario, the ball will eventually stop moving due to external forces such as air. 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. 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. will differ from the height that the ball would have reached had it been dropped in a vacuum. This project guide contains information that you need in order to start your project. This means that the faster that the ball travels the larger the force of air resistance upon it. This means that KE is the same for both balls when each ball hits the ground. Stop procrastinating with our study reminders. Therefore of the GPE that the ball possessed at the beginning some energy is given off as thermal energy. Review each step of the procedure to find sources of potential errors. ", " My husband and son came with me for the tour. Materials:-Carbon Paper-Goggles-Golf A ball falls from a height of 3 metres. External factors, i.e. 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. A bouncing ball is an example of oscillatory motion as the ball is oscillating about the equilibrium position. Therefore the height that it reaches is less high. Your assistant will record the bounce. The higher the ball goes, the more GPE it ends up with. Have all your study materials in one place. If you are author or own the copyright of this book, please report to us by using this DMCA report form. WebControl Variable: Simple Definition. Hence the final answer is: \(\text{Total distance} = 2 \cdot S_n = 2 \cdot 9.6 m= 19.2m\). WebLearn how to identify types of variables in a simple experiment with bouncing balls. Hold the ball at 6 feet height and release it. If the coefficient to restitution = 0.7, a ball dropping from h1in a vacuum would reach the height of 0.7 h1 after bouncing. When dropped on a solid surface, not even a super ball bounces back as high as its initial height, but some balls do bounce a lot better than others. It is always important for students, parents and teachers to know a good source for science related equipment and supplies they need for their science activities. Type your answer here: The independent is the variable you change, The dependent variable is the variable you observe to determine the impact of the independent variable, and control variable is the constant, which is something that is assigned a value, and it will not change in the experiment. Several new questions may have occurred to you while doing experiments. At the terminal speed, the drag force = the gravitational force. Once the ball hits the ground, its displacement is momentarily zero. Is a bouncing ball an example of Newton's third law? This causes the amplitude of the height to reduce over time and eventually come to a stop due to friction forces like air resistance, which are assumed to be zero in an ideal scenario. This will help with your understanding of the investigation and lead you to make a possible hypothesis. Also its Gravitational Potential energy is decreasing because its height is decreasing. Material that you may test are: Carpet, Rubber matte, ply wood, sponge, Styrofoam, another ball, . 8. Variables are the factors that are changed, measured or controlled. Course of Theoretical Physics : Mechanics (Course of Theoretical Physics), Engineering Mechanics Dynamics (11th Edition). Several meter sticks for measuring the height of the bouncing ball or drawing a larger meter stick. Therefore the ball goes higher. Additional list of material can be extracted from the experiment section. This will be called the average of the middle three repeats. Then when dropping the ball again eye level will be kept level with the blue tack thus avoiding parallax errors. Use the pencil and ruler to connect the incoming and outgoing trajectories of the marble to the point where the marble bounced off the wood. 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. You can drop the ball from your hand or you can make a stopper for the ball to hold it only from the sides with a little pressure. It will be important to keep track of what times go between what bounces. Use a racquetball, a golf ball or any kind that bounces well and makes a nice crisp sound when it bounces. Projectile motion is the motion of objects that are moving near the surface of the earth in a curved path due to the effect of gravity. These two results were excluded when averages were being calculated and therefore the average variation between results used for calculating the average was even less than 3cm. The ball moves upwards, reaching stage 1, i.e., maximum height, and its velocity is momentarily zero. What does the motion of a bouncing ball look like? When you hold a ball above a surface, the ball has potential energy. Something about its situation then must determine its rebound, but what? In this experiment there are FOUR VARIABLES. The mass is cancelled out in the above equation, and we re-arrange with respect to velocity. For example this is a sample explanation. This would allow the actual coefficient to restitution to be calculated. The selection of balls for official games in most sports (esp. It is a separate experiment, done exactly like the others. The experiment was conducted as the method (below) states. This therefore provides accurate and reliable results. Heres an example of an Excel spread sheet that analyzes whats going on: Heres a graph of energy vs. bounce from the spread sheet: Purpose: To determine how high a tennis ball will bounce when dropped from a specific height. , v is greater therefore KE is greater by a larger amount). D (60%) WebThe Bounciest Ball Experiment Overview: In this lesson, students conduct a series of experiments with different balls to observe which bounce the highest and to see how they could make balls bounce higher. The purpose of our lab was fulfilled. The balls are shown at rest, about to bounce back up. This produces a different amount of response in the system. 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. What factors affect the bounce of a dropped ball? This would eliminate parallax error further. If you have any questions or need more support about this project, click on the Ask Question button on the top of this page to send me a message. What are the variables in the ramp experiment? Use two people to measure the results; one person to drop the ball and one to measure the height to which it reaches after bouncing. This applies to a ball falling in a vacuum. For a falling object the Coefficient to restitution (C, ) is equal to the velocity squared as the object is travelling at as it leaves the floor (v, ) divided by the velocity squared as it hits the floor (v, If a ball is dropped in a vacuum. 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. You will be able to precisely measure the time intervals between bounces. This causes thermal energy to be given off. This means for the ball to reach terminal velocity the drag force has to be bigger and for the drag force to be bigger the ball has to fall faster (so that more air particles hit the ball every second). When you think you know what variables may be involved, think about ways to change one at a time. Both potential and kinetic energy have units of Joules (J). A single experiment may contain many control variables. I called School Time and my husband and son came with me for the tour. Using the trends in your experimental data and your experimental observations, try to answer your original questions. The difference between the predicted height and the actual height will provide evidence as to how air resistance affects the flight of the ball. are 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. Measuring the height to which the ball bounced on subsequent bounces would be interesting, seeing if h. Using the geometric sequence formula, the sum of the terms which are the heights of the ball after each bound: \(S_n = \frac{\alpha(1-r^n)}{1-r} = \frac{6m(1-0.38^5)}{1-0.38} = 9.6 m\). The higher the height from which the ball was dropped from, the higher the height to which it bounced. In the bouncing ball example, external forces such as air resistance are assumed to be zero. 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. 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. 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. This is impossible. What type of motion does a bouncing ball experience? The balls finish up with the same amount of energy and the only energy given out is thermal energy. Grades: Preschool and K-2 Length of Lesson: Approximately 45 minutes Related Video: The Hawk Factor episode Learning Goals: The motion of the ball can be split into different stages depending on the direction of the velocity vector; these stages are listed below. The change in direction when the ball reaches the ground causes a momentary acceleration as seen in the acceleration graph (as acceleration). As it did so the downward force was partially balanced out by the upwards force of drag, increasingly so the closer the ball got to its terminal velocity. Method:The apparatus will be set up as shown: H is the height of the ball before it is dropped. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. This means that the faster that the ball travels the larger the force of air resistance upon it. Therefore any change to the height from which the ball starts with affects the height to which it bounces to. Many questions are related. This is correct unless the ball shows signs of reaching terminal velocity. Discussing the variables involved in this experiment. The variable to be changed in the experiment is the drop height, therefore the drop height will be the independent variable investigated. The effect of changing the drop height will be measured by calculating the bounce efficiency of the tennis 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. Yes, as the ball is oscillating about the equilibrium position (in height) and goes back to its initial position after a period of time. If you choose to study on any other variable, following are samples of hypothesis. 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. Also it shows inaccuracies in the experiment as it shows that heights were recorded that exceeded the height that the ball would have reached had it been dropped in a vacuum. Once the drag force equals the gravitational force all forces are equal and acceleration stops. The ball then rebounds: it undents and tosses itself up into the air to a good fraction of its original height. Why if you drop a ball from say 2 meters does it bounce higher than a ball dropped from 1 meter? or hold Ctrl and then use arrow keys to move the wave 0.01 second left or right. WebVariables: Height from which the ball is dropped Mass of the ball Material ball is made from External factors, i.e. of the users don't pass the Bouncing Ball Example quiz! This is because it is easiest as the figure read of the meter rule is the result. After the ball reaches terminal velocity, no more GPE is converted into KE is the ball cannot get any faster. This phenomenon is described by Newton's third law. The most valuable resources for teachers and students. That height fraction is equal to the fraction of energy that the ball successfully stored and returned during its bounce. B) Using the conservation of energy, find the velocity of the ball before it hits the ground from a height of three metres. Air resistance exists but does not affect the velocity of the ball significantly. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. WebBouncing Ball Experiment. The energy that the ball hits the floor with is kinetic energy. Possible sources of error include several types of measurement errors. So, we equate the potential energy and the kinetic energy. Using the geometric sequence for an infinite sequence and substituting the given values we get: \(S_{\infty} = 2 \cdot \frac{\alpha}{1-r} = 2 \cdot \frac{6m}{1-0.38} = 19.35 m\). This is repeated three times at 5 different heights. For each run, a different amount of change in the variable is used. C) Frozen tennis balls will not bounce as high. Averages are more reliable than using one result as they take into account variation between results. 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. 2. The following is a college level project, but some grade 9 to 12 students can also complete this with no problem. Air density will not change enough to affect the flight of the ball seeing as all the results will be collected during a brief period on one day. 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. You measure this response, or record data, in a table for this purpose.