WebA control variable (or scientific constant) in scientific experimentation is an experimental element which is constant (controlled) and unchanged throughout the course of the The balls leave the floor at the same speed with the same amount of KE and so both balls reach the same height and end up with the same amount of GPE at the top of their bounces. The distance in centimeters from bounce 1 to bounce 2. These equations allow us to predict how a change will affect the system without the need to do additional experiments. So an imperfect ball loses some energy on each bounce. Its a good idea to bounce it on a level surface, and dont release from too great a height, or while bouncing, the ball will wander away from the sound recorder range. 8. The slope of the line in graph 1 was found to be 0.5. Be perfectly prepared on time with an individual plan. of the users don't pass the Bouncing Ball Example quiz! Several smooth hard flat horizontal surfaces suitable for bouncing ballsfloors, lab tables, sidewalks, and the like. 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. 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). What is the control variable in the bouncing ball experiment? 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. In this experiment you will test the bounce of a dropped ball for different surface hardness. For this reason, its also known as a controlled variable or a constant variable. or hold Ctrl and then use arrow keys to move the wave 0.01 second left or right. The exact interval will be determined after the preliminary experiment, as will the number of heights that the ball will be dropped from. To find out what affects the height to which a ball bounces. The purpose of our lab was fulfilled. Dependent Variable: The height of the bounce. Yes, as the ball receives a force from the ground due to collision, which causes the ball to bounce off the ground. This denting extracts energy from the balls motion and stores much of it in the elastic surfaces of the floor and ball. We can go back to our table of velocities, square each one, then multiply by 1/ 2 * 0.044 kg to find the kinetic energy at each moment. 15 inches, and the golf ball bounced 26 inches. Many questions are related. Drag is a squared function of velocity and therefore as the ball drops drag increases a greater amount each second. I plan to collect at least ten results as this will make the conclusion and graph I am able to draw from the experiment more accurate than if I had less results than ten. Variables - The Tennis ball experiment tennis and baseball) includes the CoR test. This means that not all the GPE is converted into KE as it would have been if the ball had been dropped in a vacuum. If the drag is less the ball will fall faster and is less likely to reach its terminal velocity. Finally, we need to multiply the distance found by 2, as one bounce of the ball includes both a rise and fall. Independent: - Type of surface the tennis ball is dropped on. In this experiment there are FOUR VARIABLES. The format you use to write your bibliography may look like this: Are you ready for more advanced ball drop projects? External factors, i.e. The drag force increases as the ball goes faster. Questions lead to more questions, which lead to additional hypothesis that need to be tested. An alternative method would be the measuring person holding a video camera level with the approximate height that the ball reaches after bouncing and videoing the ball reach the top of its arc. 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. Following are some sample information that you may find: Everyone has played with balls that bounce, but few people truly understand the physics behind a bouncing ball. The difference between the predicted height and the actual height will provide evidence as to how air resistance affects the flight of the ball. Does a ball bounce higher or lower in moon (Less Gravity), while all other conditions are constant? While these variables are not the A decrease in m, assuming g and h1stay constant, results in a decrease in m g h1which results A decrease in m, assuming g and h1stay constant, results in a decrease in m g h1which results in a decrease in GPE. This would allow one to find the terminal velocity of the ball. 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. We felt the magic immediately. An elastic surface such as rubber and a very hard surface such as concrete will result the highest bounce level. What is the velocity of the ball at the point of maximum height? Why if you drop a ball from say 2 meters does it bounce higher than a ball dropped from 1 meter? Grades: Preschool and K-2 Length of Lesson: Approximately 45 minutes Related Video: The Hawk Factor episode Learning Goals: 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. The answer lies in how far the ball has dented inward due to its collision with the floor. Dropping a ball from different heights Dropping a ball from different heights could affect So if we double the air pressure, we will get double bounce height. Click Create Assignment to assign this modality to your LMS. WebControlled Variables: Bouncy ball used, surface bounced off of, technique in which ball was dropped (initial height was measured from base of ball). Working out the variation in results shows how accurate the experiment was. Five repeats were done as it was deemed that an average of the middle three was reasonably accurate. Hold the ball at 6 feet height and release it on a hard concrete surface. Therefore any change to the weight of the ball will affect the energy the ball has initially, which, as previously stated, affects the height to which the ball bounces. Specifically, you are tasked to determine: B.) There are three types of variables: Controlled Variables: You can have as many controlled variables as you like. D (60%) Once the drag force equals the gravitational force all forces are equal and acceleration stops. If you follow the motion of either ball, youll realize that theres a moment halfway through its bounce when the ball is perfectly motionless in contact with the floor. http://wings.avkids.com/Curriculums/Tennis/index.html. 1. The acceleration due to gravity causes the ball to change direction and start moving downwards at stage 2. Bouncing Ball Experiment Our simple experiment is to drop a ping pong ball weighed at 3 grams from a height of 1 metre then 90cm, 80cm, 70cm, The coefficient to restitution can be found out from a graph of, it follows the gradient of the graph change in h. . This would allow the actual coefficient to restitution to be calculated. Report DMCA Overview his the height of the balls bounce. 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. Locate the peaks and record the time for each peak. 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 experiment was conducted as the method (below) states. Bouncing balls AT (Year 8 Schematic diagram of two balls dropped from different heights. Do you think e is constant for your ball? For a dropped ball, the total mechanical energy is defined as the sum of its kinetic energy and its gravitational potential energy. These inaccuracies could have been caused by external factors or parallax error even though efforts were made to avoid parallax error occurring - by dropping the ball one time that was not measured and placing a blob of blue tack onto the meter rule at the approximate height it bounced to. Test your knowledge with gamified quizzes. This experiment would provide me with more results that are relevant to the experiment that I have already conducted. 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. Conveniently enough, this fraction of returned energy is nearly independent of how much energy the ball had to begin with. The purpose of this project is to find out what factors affect the bounce of a dropped ball. 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. As elasticity and hardness decreases, part of the ball energy will be used to permanently dent or misplace or vibrate the surface, so ball will have less energy to bounce. This is in accordance with Newton's second law. Then change the surface material by covering it with different material and repeat the test. Record the results in a table like this: Divide the bounce height of each row by the release height of the same row and write the result in the last column. This would provide evidence on how the height from which the ball is dropped from affects the height to which it bounces without air resistance. 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. Often, mathematical equations can be made from graphs. GPE=Mass (kg) Gravitational Field Strength (N/Kg) Height (m). The bounce of a dropped ball has a direct relation with the release height. For the lowest three points air resistance is approximately equal to zero due to the ball having a low velocity, as it was dropped from a low height, and therefore hits less air particles per second than a ball traveling at a faster speed. 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. When the ball collides with the floor, the ball becomes deformed. 2. 1. Create and find flashcards in record time. This is because as the ball goes faster it passes through a greater volume of air each second. 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. If the KE is the same as they hit the ground the energy stored in the ball as elastic potential energy will be the same also. 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 . Instead, as the ball is still always loosing GPE so long as it is still falling, all GPE is converted into thermal energy. Use a racquetball, a golf ball or any kind that bounces well and makes a nice crisp sound when it bounces. 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. They identify variables to be changed, measured and controlled. Both potential and kinetic energy have units of Joules (J). This is impossible. StudySmarter is commited to creating, free, high quality explainations, opening education to all. Using the slope and graph, we can estimate that the ball would bounce to 0.75 m if dropped from 1.5 m and bounce to 1 m if dropped from 2 m. It is difficult to say with certainty that a ball dropped from 100 m would bounce to 50 m. That is because the heights we dropped the tennis ball from were all under 1 m, and at a much greater distance there may be other factors that would contribute to the bounce height. A series of experiments can be done by changing one variable a different amount each time. The coefficient of restitution is the ratio of the final to initial speed between two bodies after the collision. 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. Summarize what happened. 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. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. Even a specific ball may bounce different heights at different times or different locations. A ball falls from a height of 3 metres. In this experiment you will measure the bounce of a dropped ball for different release heights. 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. (The upward direction was assumed to be positive in this example. If the common ratio of the sequence is between 0 and 1, then the term r would approach zero. Repeat your tests 9 more times and each time lower the release height for 6 inches. Now is the time to pull together what happened, and assess the experiments you did. The results of our experiment show that this probably is not the case. At 2ft, the basketball bounced 15 inches, the tennis ball bounced 12 inches, and the golf. Keep track of where you got your information from. With no net force, the acceleration = 0 and the ball falls at a constant velocity. When the ball rebounds, its stored energy reappears and it leaps higher into the air than it would have had you dropped it a shorter distance. So, we equate the potential energy and the kinetic energy. 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. From this it can be seen that using the average of the middle three results is more accurate than using the average of all five, as it automatically discounts most anomalies. Figure 1. For instance result 3 from 200cm was an anomaly but was not taken into account when taking the average of the middle three. 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: WebLearn how to identify types of variables in a simple experiment with bouncing balls. Identifying variables is necessary before you can make a hypothesis. 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.

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