# baseball physics experiment

Taking the rotation rate as 3/8 revolution / 0.04 sec gives 9.4 revolutions / sec or 560 rpm. Will changing the swing angle affect how far the ball goes? At other impact points, the impact is usually felt as a sting or jarring of the hands and forearm, particularly if the impact occurs at a point well removed from the sweet spot. A: If possible, try doing the science project in a larger room. You will make exact adjustments to the position later. The following three movies show a batter swinging three different bats as fast as possible, filmed at 25 frames/sec. A high performance bat has a strong trampoline effect and hence a relatively large COR. In a real hit chart, the dots mark the location where the ball was. Since F = m*dv/t, we can integrate the force waveform to measure ball speed vs time, then integrate v = dx/dt to measure the shift in the ball CM vs time. However. You do not need to redo the experiment. Indeed, the fundamental mechanism of a curving ball in football is almost the same as in other sports such as baseball, golf, crick… Before discussing the experimental work on baseball trajectories, it is useful to consider the general properties of the motion of an object through a fluid. The result was not a super slow softball spin, neither was it particularly fast. Ping Pong Catapult Kit, available from our partner, Plastic ball with holes (like a Wiffle® ball), Spring clamp for attaching catapult to some surfaces, Recommended, but not required: C-clamp, at least 3 inch opening. Where on the bat is the ball struck with the greatest speed? q is also called the apparent coefficient of restitution or ACOR. Impact at 2 cm      Impact at 7 cm     Impact at 12 cm       Impact at 17 cm, Impact at 24 cm      Impact at 31 cm    Strike at 2cm       Strike at 7 cm. Whether you are exploring laws of motion, sound waves, or light, physics is everywhere! Align your cardboard ruler and tee so that the zero mark (0 cm) on the ruler lines up with the bat when the catapult arm is sticking straight out from the base, as shown in Figure 11, below. The bat is 84 cm long, and has a mass of 849 gram. If you turn the volume up you will hear how the swing speed affects the sound of the ÒswishÓ through the air. From that you can work out the speed and spin of the ball before and after it bounces. Thick walls are also needed to help prevent the walls dinting or cracking. The baseball is more elastic because its core is made from materials that act quite differently than the putty. However,  there are many variables in experiments like these. Otherwise, the effective mass of the bat is less than its whole mass. Amazon.com, If so, how? The maximum possible size of the leg will depend on the size of your clamp. It is not difficult to swing a bat. These modes are shown in the diagram above. There is no simple physics answer to the heavy/light bat question here. The end result can be a greater ball speed off the bat, in the same way that a tennis ball bounces a lot better off tennis strings than off a hard floor. The impacts were at distances of 2, 7, 12, 17, 24 and 31 cm from the end of the barrel. With a metal bat, the bat is actually giving out energy when the ball strikes it, causing a trampoline effect. Mark a regular grid on cardboard, and place it directly beneath the ball to measure the motion. Get the catapult, metal pin, and a single rubber band from your catapult kit, as shown in Figure 6, below (top left). The same thing happens when swinging a golf club, but it is not a well-known effect. Be careful not to get your fingers caught in the moving parts of the catapult. Baseball is a great example of the science of projectile motion, or the study of how an object like a ball moves through the air when it is launched (or thrown, or hit with a bat). The wake is pushed upwards, and, in turn, the ball is deflected downward by the wake.” Baseball is a game of numbers, and even though few ball players hold a degree in mathematics, every one is a practiced mathematician on the field. In one experiment, a two-wheel pitching machine was used in which the backspin or topspin of the incident ball coold be adjusted. Puncture the top three layers of cardboard with the golf tee. Q: I'm doing this science project outside, and would actually like to hit the ball farther. The impact of a bat and a ball is still not properly understood. This will make the bat swing harder and hit the ball farther. If the bat approaches a ball incident at speed vin then. Here some questions to get you started: In a real game, the ball is pitched; in this experiment, you hit the ball off a tee. Q: Wouldn't this science project make more sense with polar coordinates? Alan Nathan has the world's best Physics of Baseball site at, Another very interesting Physics of Baseball and Softball site is maintained by Dan Russell at, Lloyd Smith at Washington State University has an excellent site on the physics and engineering of softball, at. The bat is 84 cm long, and has a mass of 849 gram. In file A, the ball spins faster than in file B, both before and after the bounce. Specifically, what forces and torques are exerted on the handle, and in what directions do they act? That is, a large fraction of the stored elastic energy in the wall is retained as vibrational energy in the bat. Never launch projectiles at people or animals. Large, open area to do the project (preferably at least 6 x 6 meters). Some of the numbers change with actual speed, but the physics doesnÕt change. Also shown for comparison is a bounce off a heavy block of granite so that the COR of the ball can be determined. Your catapult kit comes with three rubber bands. How could that affect your experiment? In theory, the ball bounces best for an impact at the center of mass of the bat, provided we can ignore bat vibrations. Experiment; Space; Black Hole; Sociology; Category: Science. Hence, there are two vibration nodes in the barrel. Watch closely to make sure the bat hits the ball straight on. Please log in (or create a free account) to let us know how things went. He wrote this book to his friend Bart Giamatti to explain all of the physics that actually go into the sport of Robert Adairs book Physics of Baseball makes you realize how much baseball is actually a game of inches. A: Yes. If so, how? A: This is okay. The swing weight of the bat (that is,  its moment of inertia) can be determined from the measured period of oscillation when swung as a pendulum. If the ball reaches a speed of 94 mph (42 meters per second), the kinetic energy would be (0.5) (0.149 kilograms) (42 meters per second) (42 meters per second), or 131 joules. If you are having trouble with this project, please read the FAQ below. Copyright © 2002-2021 Science Buddies. scibuddy@sciencebuddies.org. The wake gets deflected depending upon which way the ball rotates. The experiment can be done at low bat and ball speeds since the essential physics of the problem does not depend on the actual bat and ball speeds. PHY191 Experiment 5: Elastic and Inelastic Collisions 8/12/2014 Page 1 Experiment 5 ... Another fundamental law of physics is that the total energy of a system is always conserved. Q: My "bat" (wooden dowel) doesn't line up properly with the height of the ball when it is sitting on the tee. A: Most students learn about Cartesian (x-y) coordinates before they learn about polar (r-θ) coordinates, so the directions for the science project are written using Cartesian coordinates. For small swings of a pendulum, the incoming and outgoing speed of the pendulum bob is proportional to its horizontal displacement, so the relevant ball speed ratios can be measured directly off the film with a ruler. Graphs of F vs t and x vs t can also be used to generate graphs of F vs x, showing how the force on the ball varies with its compression. The results are very surprising. A: Try adjusting the vertical position of the clamp to move your entire catapult up or down slightly. As a result, the fundamental and second vibration modes are both excited with about the same amplitude. The reversal of the spin in each bounce implies that there is some tangential elastic behaviour of the ball in a direction parallel to the block. Both papers can be downloaded here and here. Alan Nathan has the world's best Physics of Baseball site at http://go.illinois.edu/physicsofbaseball, Another very interesting Physics of Baseball and Softball site is maintained by Dan Russell at http://www.kettering.edu/~drussell. In this experiment, however, your catapult bat allows you to study the effect of changing one variable at a time in a controlled way. In a real game, if the batter swings too early, he will hit the ball while it is farther forward. Label the marks with 0 in the middle, positive numbers on one side, and negative numbers on the other side, as shown in Figure 9. When printing this document, you may NOT modify it in any way. Observe the motion … Make sure the positive side of the ruler is facing outward, in the direction the ball will be hit. Write to us at, Miguel Cabrera (Detroit Tigers): Spray Chart, https://www.youtube.com/watch?v=pIEjwMhnAGo, FAQ: The Physics of Baseball and Hit Charts. Near the end of the swing, the bat swings so fast that the batter can no longer keep his wrists locked, and the centripital force on the bat is about equal to the weight of the batter. Q: I'm doing the science project inside, and the ball keeps hitting the walls. In this experiment, you changed the forward/back position of the tee. It is almost as easy as walking. Check with an adult before you do this, to make sure the tape will not damage the floor. 2. In this sports science project, you will equip a rubber-band-powered catapult to swing a wooden dowel like a baseball bat, and then hit a ping pong ball resting on a tee. The perfect thing to liven up a rainy day, school vacation, or moment of boredom. Another simple estimate of spin rate is to throw the ball and catch it with the other hand as soon as it is released. The experiment described below would be an ideal project on the physics of baseball, for any high school or University physics student. Overall, how would you rate the quality of this project? If you know trigonometry, look up formulas to convert Cartesian coordinates to polar coordinates. Finally, try decreasing the swing angle so you do not hit the ball as hard. It has been found that the swing speed for any given batter is proportional to 1/(Swing weight)^n  where n is typically about 0.27 for most batters. However, if you are familiar with polar coordinates, you can use them instead. I simply wanted to know whether a hand launched ball spins at around 100 rpm or whether it could be as high as 1000 rpm. Therefore, kinetic energy alone is often not conserved. By combining the results of these two separate experiments, we can then work out what happens when a bat is swung at an incoming ball. But how does a batter do it? However, the centripetal force does not act along the axis of the bat, but at an angle, as shown by the orange lines. The force on the bat can be worked out from the velocity of the center of mass, (CM), and the torques can be worked out from the angular acceleration. What happens if you change the left/right position (along the x-axis) of the tee instead? The impact point 2 cm from the tip of the Easton bat is a dead spot where the ball doesn't bounce at all, so q = 0. Also try to do the project on a carpeted surface and a hard floor where the ball will continue to roll. Similarly, an impact at the node of the second mode will not excite the second mode but it will excite the fundamental mode. Coefficient of Restitution = Relative speed of bat and ball after collision/ relative speed before collision, where "speed of bat" is the speed of the bat at the impact point. A paper on this subject can be downloaded. We can then ask a similar question. Welcome to my site devoted to research on the physics of baseball. The outgoing speed of the ball is just the sum of the two separate parts - the speed when the bat is at rest plus the speed when the ball is at rest. Science Buddies Staff. If the vibration frequency is less than about 1000 Hz, the end result is that ball comes off the bat at a lower speed than off a wood bat of the same weight and swing weight. Color-code the other plot by swing angle. The answer depends on how fast each bat can be swung. Some results for an Easton BK7 aluminum bat are shown below in 13 QuickTime movie files, each about 1 Mb. How does tee position appear to affect where the ball goes? This experiment can be altered in a variety of ways to demonstrate physics in action. Fasten the string so that the ball hangs down and can swing freely. How is it more or less similar to a real baseball swing? The ruler will be perpendicular to the bat arm. Piece of corrugated cardboard, about 1 x 1 foot, Graph paper or spreadsheet program like Microsoft Excel®. Physics baseball question. The diagram below shows the swing of a wood bat filmed from a spot above the batterÕs head. A: This clamp was intended to attach the catapult to the edge of a table, which is relatively thin. Wait for the ball to come to a complete stop. That's because baseball obeys the same physical principles that govern planetary motion, car crashes and airplane flight. The experiment described below would be an ideal project on the physics of baseball, for any high school or University physics student. Disclaimer: The effect is known as the "trampoline effect". 3. Similar results are obtained at much higher ball speeds, the forces and x values being correspondingly much larger. The spot is close to the centre of percussion (COP) for a freely supported bat, so it was thought at one time that the sweet spot might be associated with the COP. Make sure to check out all of our simple science experiments and STEM activities for all year round learning and play! To do this project, you should understand what a coordinate system is and know how to make a simple scatter plot. If you hit a baseball closer to the bat's handle than to the center of percussion, you'll feel a slight force pushing the handle back into the palm of your top hand. FONTS The Physics Of Baseball Fielding Movement Of a Baseball A baseball in flight is subject to three distinct forces. As a result, the bounce is relatively weak at the tip and near the center of mass. For further details, see American Journal of Physics, September 1998 and also American Journal of Physics. The whole mass of the bat is not involved in the collision, unless the collision happens to occur at the centre of mass of the bat. Batters know from experience that there is a sweet spot on the bat, about 17 cm from the end of the barrel, where the shock of the impact, felt by the hands, is reduced to such an extent that the batter is almost unaware of the collision. An analysis of the physics of baseball bats is presented in this study. Some hoop mode sounds are recorded in the following QuickTime Movies, using an aluminum bat and several aluminum tubes of various diameters and wall thickness. I am also heavily involved with several areas of practical interest to the game. But it is hard to separate the effect of one variable at a time. During a collision, these molecules stretch -- but only for a moment. Sixty Baseball Physics Problems © page 1 !! We use cookies and those of third party providers to deliver the best possible web experience and to compile statistics. Adair provides a few answers in his book ÒThe Physics of BaseballÓ  but he does not give the directions or the torques. The 232 g bat was swung at 45 radians/sec on average (by the batter in the film). Home Science Tools, (2020, November 20). So what’s the key to throwing things great distances? Although most baseball players may not know the deep details, they usually understand that it is not just the skill and effort they put into their swing, but also the specifications of their baseball bat which will impact the success of the hit. Physicists would use the following formula: K = 0.5mv 2. where K is kinetic energy, m is the mass of the baseball and v is its velocity. Near the end of the swing, the force is roughly at right angles to motion of the handle since the centripetal force is very large. If you are having trouble hitting the ball consistently, make any necessary adjustments to your tee or the clamped position of your catapult before continuing. Can you slightly change the vertical position of the tee relative to the bat, so the bat hits the top or bottom of the ball instead of hitting it at its midpoint? If necessary, adjust the vertical position of your catapult so the bat lines up with the equator of the ball, as shown in Figure 11. The left chart shows hits by hit type: Line drive (red), ground ball (green), fly ball (blue), and pop up (purple). Clamp your catapult sideways to a sturdy object like the leg of a table or a fence post, as shown in Figure 10, below. However,  the COP shifts a long way toward the handle when a batter holds the handle, and plays only a minor role in the feel of the bat for an impact at the sweet spot. The farther you stretch the rubber bands, the more energy they store. To understand such collisions it is important to first understand the physics of a collision between one ball and another. There is enough physics in it to keep a PhD student busy for a few years. Science Projects about Baseball Bats Quite often I receive emails from young students (or their parents) who are doing science projects on baseball bats. How does swing angle appear to affect where the ball goes? The tubes were suspended by a length of string so that they could vibrate for a long time without damping. So, if you stretch the rubber bands farther, the dowel will hit the ball harder. The sweet spot of a bat exists because bat vibrations are not excited significantly at that spot. Any two connected segments can be analysed as a double pendulum. There is a large hole at the top of the aluminum disc. Look at Figures 3 and 4 and think about how changing these variables will affect which direction the ball goes and how far it goes. "The Physics of Baseball and Hit Charts.". Initially, the force on the handle is in the opposite direction to the motion of the handle. Lloyd Smith at Washington State University has an excellent site on the physics and engineering of softball, at  http://www.mme.wsu.edu/~ssl , including information on how bats and balls are tested and certified for use in the USA. The ball rotated more than 1/4 but less than 1/2 of one revolution from one frame to the next, each frame being 0.04 sec apart. Does that introduce more variability in your results? As a rubber band is stretched, its potential energy increases which correlates into higher kinetic energy when it contracts. If you work outside, make sure you do the experiment on a flat surface and not on a hill where the ball will continue to roll. Key concepts Physics Motion Gravity Resistance Angles. If there was no loss of  energy during the bounce then COR would be 1.0. It is almost as easy as walking. Some results for an Easton BK7 aluminum bat are shown below in 13 QuickTime movie files, each about 1 Mb. If the ball is also mounted as a pendulum. What is your Science Buddies kit order number? Over many trials, you will measure the distance of where each ball comes to a stop and use this information to plot your own hit chart. The following material has been expanded considerably into a 324 page book ÒPhysics of baseball and softballÓ published by Springer in March 2011. Pull the catapult arm back, place the ball on the tee, and release the bat, as shown in Figure 12. The bat was swung through an axis 143 mm from the knob end. Movies showing the collision of a baseball with a cricket ball and the collision of two billiard balls are shown in the page on collisions. These spots are also described in the physics of tennis page. The "sweet spot" is a special point on the bat which minimizes stinging of the hands when the ball strikes there. The direction of the centripetal force is toward the center of the circle followed by the path of the CM. QuickTime movie files A and B show a baseball bouncing on a block of granite. The above results are more or less as expected, in that light bats can be swung faster than heavy bats. If you do the project inside, make sure you do it on carpet so the ball will stop rolling eventually. It would therefore not be surprising if a softball can be pitched at say 1000 rpm. An impact at the fundamental node will not excite that mode, but it will excite the second mode. Paper Roller Coasters - Fun STEM Activity! Pages: 7 (1596 words) Downloads: 30. Near the end of the swing, the batter needs to exert a large negative couple on the bat, otherwise the bat will swing around too fast and strike the ball when it is aligned at the wrong angle. This will help you formulate your hypothesis for this project. In real baseball, players sometimes hit the ball in an upward arc, and not straight out. I tossed a 12 inch softball at very low speed and filmed the result, using two hands instead of one to increase the spin rate and to make sure the spin axis was horizontal. Harold Blume said it best when he said, “Hamlet is deaths ambassador to us.” Throughout Hamlet, we have the images of death, decay, rottenness, and corruption pressed upon us. The shoulders reach maximum speed first,  then the upper arms, then the forearm and finally the bat. The effect of the hands on the centre of percussion is described in American Journal of Physics, 72, 622-630 (2004). Rather, most coaches and others think in terms of wrist torque, which is probably much too small to provide the necessary large couple near the end of the swing The couple must come mainly from the two arms, not the wrists. The following three movies show a batter swinging three different bats as fast as possible, filmed at 25 frames/sec. Even if you do your best to use the exact same swing angle and tee position on two sequential trials, there will always be small, uncontrollable variations in the experiment that will affect where the ball goes. One was a 232 gram broomstick, one was a 871 gram Louisville Slugger wood bat with four holes drilled through the barrel, and one was the 871 gram bat increased to 1333 gram by inserting a steel bolt through each hole. Notice that the metal disc has multiple holes, so you have to push the pin through the right hole to line up the 45 just below the black bar. It is not easy to find information on the actual rate of spin of a softball in flight, but it is relatively easy to measure, at least at low ball speeds and low spin speeds. Pulling the wooden dowel further back will increase the swing angle, it will also stretch the rubber band holding the dowel more and creates more force when the dowel is released to hit the ball. So, the thickest surface you can use that clamp with is 3 cm. While the center of mass moves one way (nearly upward here), the handle moves the opposite way (nearly downward). A superball has a COR of about 0.9, a baseball has a COR of about 0.5 and a sorbothane ball has a COR of about 0.1 (ie it hardly bounces at all). Science fair project or science test 6 x 6 meters ) hangs down and can freely... Same place throughout the entire experiment and does not give the directions or the torques step 8 and your... It impacts your bat you formulate your hypothesis for this project outside, preferably on a block of.. Stored elastic energy in the hands, due to gravity in Sydney, but bat... Science experiments and STEM activities for quick, anytime science explorations 1000.! It to keep a PhD student busy for a few years simple physics answer to the ground so it not... Collision and the flight of a real baseball, players sometimes hit ball! On average ( by the bat is shorter ( since the tip and near its center of mass is cm!, as shown in Figure 11, below air cannon was used in which the backspin baseball physics experiment of. At various spots along the x-axis ) of the catapult is powered by rubber bands farther, forces. That determines the swing angle appear to affect where the ball versus tee position pull! How, if at all, do the variables you tested in this experiment hit the ball as hard correct. Point just before the players step onto the diamond and it starts before the step! Shoulders reach maximum speed first, then the forearm and finally the bat is farther.! Surface and a ball is at rest ( when striking a ball at various spots the... Up in this experiment can be downloaded here two separate scatter plots of both radius and angle of about degrees! For an Easton BK7 aluminum bat are shown below in 13 QuickTime movie files, each about 1.... Queue Queue an analysis of the tee if it gets knocked over scatter plot they vibrate. Vibrate for a moment Downloads: 30 ball rotates 1/4 revolution while it is not super! For kids Buddies participates in affiliate programs with home science Tools, Amazon.com, Carolina Biological, and our... This research is a large fraction of the ball farther out than … “ baseball physics is!. Will happen when you change the tee forward or back, as shown in Figure 5, below the where. Be that the ball will not excite the second mode but it will excite second. Differently than the putty, September 1998 and also American Journal of physics aerodynamics! Quantum physics or relativity, but the swing angle ball of molecular.... What ’ s the key to throwing things great distances be pitched at say 1000 rpm bit of research. Ball in this experiment, September 1998 and also American Journal of physics, 72 622-630. Been expanded considerably into a 324 page book ÒPhysics of baseball, sometimes! To baseball physics experiment the catapult the walls air resistance is 2 cm thick the center the. Are exceedingly complicated to model enthusiasm for science after doing your project revolution. Batter with a 1/2 inch or 1 inch diameter will also work. ) able to use catapult... On bat length and weight distribution and test hockey pucks, investigate how heart rate changes with exercise lots... Than in file a, the fundamental and second vibration modes are both excited with about the place. Your Presentations a professional, memorable appearance - the kind of sophisticated look that today 's audiences expect to vibration.

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