2. eBook_Figure Skating Spins_2

Figure Skating Spins Volume 1, Issue 2 November 2017 Supervising Teachers: Alexandros Markoulakis Eugenia Potiriadou 2nd General Lyceum of Kamatero 1

CONTENTS Volume 1, Issue 2 November 2017 2nd General Lyceum of Kamatero Inside this issue: Front Cover 1 Contents 2 Worksheet 3 Our Video 5 Some More Data 6 Our Prezi 8 What Physics tells us 9 What Physical Education tells us 13 Sport Science Stories 22 Photos 26 Back Cover 29 2

Figure Skating Spins 2nd WORKSHEET 22/10/2017 Supervising teachers: Alexandros Markoulakis Eugenia Potiriadou What You Need A chair that 1 2 Gym 2 Weights or 2 soup cans (full) What You Do A friend 3 1. Grab one weight in 3. When you are spinning fast, pick up Grab a chair each hand and sit in the your feet. Have your friend count how chair. Stretch your arms many revolutions you make before the that spins and out to your sides, parallel chair comes to a stop. 2 gym weights to the ground. 4. Now get the chair at the same speed to test how 2. Start spinning the and cross your arms tightly to your chest. figure skaters chair by pushing off the How many times did you go around? floor with your feet. (Your can increase friend could also help by speed in a pushing you around by spin. your feet). 3

School: 2nd General Lyceum of Kamatero This worksheet’s activities as well as 2ο GENERAL LYCEUM OF the following activities/exercises should KAMATERO be uploaded (as videos, pictures, ppt, Phone: ........................ word etc) on the Twinspace platform. Fax: ..................... E-mail: [email protected]  Write and explain the theory Deadline: 06/11/2017 (equations, conservation laws etc) behind the conservation of angular momentum that causes the skater’s spin to increase as she pulls her arms in toward her body.  Find and write down stories about skaters that you think they are worth mentioned. What’s Going On? You spun more times with changed was your radius. your arms crossed, didn’t How? you? That’s due to a phys- ics principle called angu- lar momentum. Angular When you stretch out your momentum is created by arms, you create a large the combination of angu- radius. When you cross lar speed (how fast you your arms over your chest, spin) and radius (the dis- you create a smaller radi- tance from the center of us. Crossed arms translate the circle you spin in to its into faster spins and more edge). spins. Let’s assume that the That’s why figure speed of your spins skaters end their rou- (outstretched arms and tines with a spin that ro- crossed arms) were simi- tates faster as they pull lar. Then we can assume their arms closer to their that your angular speed bodies. was consistent. So, what 4

Our video Volume 1, Issue 2 November 2017 2nd General Lyceum of Kamatero https://youtu.be/UJqsepAeQwY YOU TUBE Επιλέξτε το παραπάνω link για να δείτε το βίντεο που γυρίσαμε στην αίθουσα γυμναστικής του σχολείου και στο μάθημα της Φυσικής Αγωγής. Select the link above to see the video that we shot in the school gym hall during the physical education lesson. 5

Some more data Volume 1, Issue 2 November 2017 While we waited to get started, John’s scream decibels were recorded and 2nd General Lyceum analyzed by an Apple application: “Decibel X”. We compared John’s of Kamatero scream with that of the teacher’s voice and that of the sound background. 6

Some more data Volume 1, Issue 2 November 2017 2nd General Lyceum of Kamatero While we waited to get started, John’s scream decibels were recorded and analyzed by an Apple application: “Decibel X”. We compared John’s scream with that of the teacher’s voice and that of the sound background. 7

Our Prezi Volume 1, Issue 2 November 2017 2ND GENERAL LYCEUM OF KAMATERO Prezi presentation 2nd General Lyceum of Kamatero Volume 1, Issue 1 Newsletter Date Select the following link or photo to get our Prezi presentation: https://prezi.com/view/1pAKRELcfLZej5lv8Obp/ Figure Skating Spins—Prezi presentation 8

Changes in the ice skater’s rate of spin Volume 1, Issue 2 November 2017 2ND GENERAL LYCEUM OF KAMATERO What Physics tells us—Some definitions 2nd General Lyceum of Kamatero Volume 1, Issue 1 Newsletter Date Angular Momentum (L) ONSERVATION OF Angular momentum is the product of the rotational inertia (I) and C CONSERVATION OF the rotational velocity (ω): A ANGULAR MOMENTUM NGULAR MOMENTUM L = I ω where, moment of inertia, I, characterizes the resistance to change L initial = L final in rotation and the rotational velocity, ω, has to do with how many degrees per second it takes to go around. If the net torque acting on a If the net torque acting on a Moment of Inertia (I) system is zero, the total system is zero, the total angular momentum of the angular momentum of the system is conserved. For straight-line motion, inertia is mass. For rotational motion, it's a system is conserved. bit more involved. Roughly speaking, moment of inertia characterizes the resistance to change in rotation. Conservation of angular momentum is the key to understanding what happens when the spinning ice skater increases her rotational velocity by pulling in her Rotational velocity (ω) arms. The rotational velocity has to do with how many degrees per second it takes to go around. 9

Momentum and Impulse Connection— The Impulse-Momentum Change Theorem Volume 1, Issue 2 November 2017 2ND GENERAL LYCEUM OF KAMATERO What Physics tells us 2nd General Lyceum of Kamatero Volume 1, Issue 1 Newsletter Date How do figure skaters exploit Newtonian physics when they spin? How ice-skaters use their arms to moderate their moment of inertia, which in turn affects the angular velocity of their spins? The biomechanics is fairly straightforward... Figure Skating Spins Conservation of angular momentum is the key to understanding what happens when the spinning ice skater increases her rotational velocity by pulling in her arms. The external torque acting on the skater about her axis of rotation is very small, so the condition for conservation of angular momentum exists. Why does her rotational velocity increase? When the skater’s arms and one leg are extended, they contribute a relatively large portion to her total rotational inertia—their average distance from her axis of rotation is much larger than for other portions of her body. Rotational inertia depends on the square of the distance of 2 various portions of her mass from the axis (I = m r ). The effect of this distance is substantial, even though her arms and one leg are only a small part of the total mass of the skater. When the skater pulls her arms and leg in toward her body, their contribution to her rotational inertia decreases, and therefore, her total rotational inertia decreases. 10

Momentum and Impulse Connection— The Impulse-Momentum Change Theorem Volume 1, Issue 2 November 2017 2ND GENERAL LYCEUM OF KAMATERO What Physics tells us 2nd General Lyceum of Kamatero Volume 1, Issue 1 Newsletter Date How do figure skaters exploit Newtonian physics when they spin? How ice-skaters use their arms to moderate their moment of inertia, which in turn affects the angular velocity of their spins? The biomechanics is fairly straightforward... Figure Skating Spins Conservation of angular momentum is the key to understanding what happens when the spinning ice skater increases her rotational velocity by pulling in her arms. Conservation of angular momentum requires that her angular momentum remain constant. Since angular momentum is the product of the rotational inertia and rotational velocity, L = I ω, if I decreases, ω must increase for angular momentum to stay constant. She can slow her rate of spin by extending her arms and one leg again, which she does at the end of the spin. This increases her rotational inertia and decreases her rotational velocity: angular momentum is conserved. This phenomenon can be explored using a rotating platform or stool with good bearings to keep the frictional torques small. Students hold masses in their hands, which increase the changes in rotational inertia that happen as the arms are drawn in toward the body. 11

Momentum and Impulse Connection— The Impulse-Momentum Change Theorem Volume 1, Issue 2 November 2017 2ND GENERAL LYCEUM OF KAMATERO What Physics tells us 2nd General Lyceum of Kamatero Volume 1, Issue 1 Newsletter Date How do figure skaters exploit Newtonian physics when they spin? How ice-skaters use their arms to moderate their moment of inertia, which in turn affects the angular velocity of their spins? The biomechanics is fairly straightforward... An Exercise 2 An ice skater has a rotational inertia of 1.2 kg·m when her arms are extended and 2 a rotational inertia of 0.5 kg·m when her arms are pulled in close to her body. If she goes into a spin with her arms extended and has an initial rotational velocity of 1 rev/s, what is her rotational velocity when she pulls her arms in close to her body? Since angular momentum is conserved: Data I1 = 1.2 kg·m 2 Dividing both sides by I 2 , I2 = 0.5 kg·m 2 ω1 = 1 rev/s ω2 = ; 12

Figure Skating Spins Volume 1, Issue 2 November 2017 MUSCLES USED IN 2nd General Lyceum 2ND GENERAL LYCEUM OF KAMATERO MUSCLES USED IN FIGURE SKATING of Kamatero What Physical Education tells us Volume 1, Issue 1 FIGURE SKATING What Physical Education tells us Newsletter Date Ankle JointAnkle Joint The calf muscles (soleus and gastocnemius) and the anterior shin section (tibialis anterior) muscles con- tract isometrically during the push-off phase and the glide phase. Knee JointKnee Joint The knee performs the action of extension (skating stride push-off) and flexion (returning the leg to the glide position). The quadriceps are made up of four muscles: vastus intermedius, rectus femoris, vastus lateralis, vastus medialis. The movements of the Three muscles make up the hamstring muscle knee are: group: Knee Extension -  biceps fermoris quadricep muscle  semitendinosus group are the key  semimembranosus muscles involved in the knee extension. Knee Flexion - Hamstring muscle group are responsible for knee flexion. 13

Figure Skating Spins Volume 1, Issue 2 November 2017 MUSCLES USED IN 2nd General Lyceum 2ND GENERAL LYCEUM OF KAMATERO MUSCLES USED IN FIGURE SKATING of Kamatero What Physical Education tells us Volume 1, Issue 1 FIGURE SKATING What Physical Education tells us Newsletter Date Hip JointHip Joint The hip joint allows for a wide range of motion providing six important movements. Many muscles cross the hip from various angles. In skating, the ab- duction, extension and external rotation motions are the three most important. Some of these muscles interface with the knee joint. The six movements of the hip joint are: 1. External Rotation - muscles of the external rota- tion turn the leg and kneecap outward. 2. Internal Rotation - muscles of internal rotation turn the leg and kneecap inward. 3. Abduction - The abduction muscles move the leg away from the midline of the body. 4. Adduction - The adduction muscle group consist of the groin muscles that move the legs toward the midline of the body. 14

Figure Skating Spins Volume 1, Issue 2 November 2017 MUSCLES USED IN 2nd General Lyceum 2ND GENERAL LYCEUM OF KAMATERO MUSCLES USED IN FIGURE SKATING of Kamatero What Physical Education tells us Volume 1, Issue 1 FIGURE SKATING What Physical Education tells us Newsletter Date 5. Extension - muscles move the thigh backward opposing the flexion muscles. 6. Flexion - muscles move the thigh toward the chest opposing the extension muscles. Trunk (Core)Trunk (Core) The abdominal and extensor muscles of the back are the support muscles that help stabilize the core area. These are the muscles that connect the lower body movement to the upper body maintaining sta- bility in the hip and lower back. The movements of the trunk are: 1. Flexion - the rectus abdominus muscles lean the chest and stomach forward. 15

Figure Skating Spins Volume 1, Issue 2 November 2017 MUSCLES USED IN 2nd General Lyceum 2ND GENERAL LYCEUM OF KAMATERO MUSCLES USED IN FIGURE SKATING of Kamatero What Physical Education tells us Volume 1, Issue 1 FIGURE SKATING What Physical Education tells us Newsletter Date 2. Extension - the erector spinae muscles of the back support the spine when it flexes forward. 3. Rotation - the external and internal oblique ab- dominal muscles control the trunk rotation. Click HERE or on the following Prezi presentation to find more information on the muscles involved in Ice Skating. 16

Figure Skating Spins Volume 1, Issue 2 November 2017 THE BENEFITS OF 2nd General Lyceum 2ND GENERAL LYCEUM OF KAMATERO THE BENEFITS OF ICE SKATING of Kamatero What Physical Education tells us Volume 1, Issue 1 ICE SKATING What Physical Education tells us Newsletter Date Better balanceBetter balanceBetter balance Ice skating helps improve your balance through fun and positive exercise. Travelling across an incredi- bly slippery surface should quickly train you to stay on your feet. Improves joint flexibilityImproves joint flexibilityImproves joint flexibility If your leg joints creak every time you rise from your bed in the morning, ice skating could offer a real solu- tion. With its emphasis on quick foot movements and strong knees, your leg joints will receive a great workout and hopefully feel more flexible in no time. Builds leg musclesBuilds leg musclesBuilds leg muscles Focusing on lower-body movement, ice skating offers great exercise for the leg muscles, building and toning them up over time. 17

Figure Skating Spins Volume 1, Issue 2 November 2017 THE BENEFITS OF 2nd General Lyceum 2ND GENERAL LYCEUM OF KAMATERO THE BENEFITS OF ICE SKATING of Kamatero What Physical Education tells us Volume 1, Issue 1 ICE SKATING What Physical Education tells us Newsletter Date CardioCardioCardio Aerobic exercise is an important aspect of cardio- vascular health, and ice skating provides a great aerobic workout. The best part about skating is you get a great cardio workout without even knowing it. EnduranceEnduranceEndurance Ice skating requires energy over an extended period of time, making it a great way to build your endur- ance. The longer you skate, the more you’ll improve your endurance, not just for ice skating but for other sports and activities as well. Weight managementWeight managementWeight management If you are trying to lose or maintain your weight, ice skating is a good way to burn calories while hav- ing fun! Ice skating burns from 300-650 calories per hour, depending on how hard you skate. 18

Figure Skating Spins Volume 1, Issue 2 November 2017 THE BENEFITS OF 2nd General Lyceum 2ND GENERAL LYCEUM OF KAMATERO THE BENEFITS OF ICE SKATING of Kamatero What Physical Education tells us Volume 1, Issue 1 ICE SKATING What Physical Education tells us Newsletter Date Stress reliefStress reliefStress relief Regular physical activity like ice skating can help combat the effects of stress. Ice skating is one of the most fun ways to exercise, especially if you skate outdoors where you can soak up the scenery and enjoy nature. Improves jointsImproves jointsImproves joints Through gliding and synchronized movement of the legs, the joints and muscles will get a great workout and will become flexible in no time. Skating is said to be more beneficial than cycling and running. Mental fitnessMental fitnessMental fitness The fresh air and sunshine in outdoor ice skating, as well as the company of family and friends, great- ly help in unwinding from a long week of work and stress. Self confidence is definitely improved as well. 19

Figure Skating Spins Volume 1, Issue 2 November 2017 2nd General Lyceum 2ND GENERAL LYCEUM OF KAMATERO of Kamatero What Physical Education tells us Volume 1, Issue 1 What Physical Education tells us Some deviations from the School Physics Newsletter Date I won a gold medal in the Isle of Wight figure skating championships in 2008. Yes, bringing the arms inward can quicken the spinning speed, but not necessarily- --the axis of rotation is not fixed and the body is non-rigid. In the `candlestick’ spin, yes, the arms point straight up the spin axis and it goes really fast. Physicists often highlight arm positions in spins, but much larger effects come from the momentum of the free leg with its extra kilogram or more of whirling boot and blade, at the far end, as in the sit-spin illustrated. A normal spin is often entered on a backward right-inner-blade-edge so the skater travels clockwise around the intended spin axis. This considerable translation mo- mentum is neutralized, off-axis relative to the skater’s centre of gravity, by a step forwards and a kick sideways with the right-blade, left arm leading, right arm trailing, onto the left-blade-outer-edge which follows a decreasing circular trajecto- ry, while the skater adjusts to semi-mechanical rigidity, having a backward mo- mentum on the left upper-body and a forward momentum on the right. This now anticlockwise angular momentum can be guided into a faster spin by bringing that whirling boot onto the rotation axis---work is done by muscles against centrifugation, so the spin energy increases. 20

Figure Skating Spins Volume 1, Issue 2 November 2017 2nd General Lyceum 2ND GENERAL LYCEUM OF KAMATERO of Kamatero What Physical Education tells us Volume 1, Issue 1 What Physical Education tells us Some deviations from the School Physics Newsletter Date But get it wrong and muscles dissipate rather than supply energy---like they do when descending stairs. A floppy spin is full of mechanical irreversibilities and rap- id entropy production. If you pull your arms carefully inwards against centrifugal forces, the spin quick- ens, but if the rotation axis changes, a retarding torque can arise from the chang- ing direction of the blade on the ice together with the spin axis increasing its dis- tance from the small moving blade-to-ice contact area. Also consider how much ex- tra circulating blood may be in the hands due to previous spins---hand, arm and leg masses vary. Far from ‘straightforward biomechanics’, the situation is full of varia- bles---gyroscopic effects, backbone flexure, blade rocking, vestibular and visual feedback, ice condition, etc. In Olympic skating you are watching the effects of very fine adjustments to many hidden variables. The best way to progress your understanding is to get some lessons and have fun. Also have a good look at the reverse curvatures of figure skating blades and how they function. http://physicsworld.com/cws/article/multimedia/2014/feb/10/how-do-figure- skaters-exploit-newtonian-physics-when-they-spin 21

SPORTS SCIENCE STORIES Volume 1, Issue 2 November 2017 HOLLYWOOD STAR 2nd General Lyceum 1. of Kamatero History—Early Pioneers  Figure skating has developed from a practical way to get around on ice into the elegant mix of art and sport it is today.  The Dutch were arguably the earliest pioneers of skating. They began using canals to maintain Sonja Henie made her Olympic debut in communication by skating from village to village as Chamonix in 1924, aged just 11, and was far back as the 13th century. Skating eventually spread across the channel to England, and soon so nervous she had to ask her coach what the first clubs and artificial rinks began to form. to do midway through her routines. How- Passionate skaters included several kings of England, Marie Antoinette, Napoleon III and ever, she won gold in the next three Olym- German writer Johann Wolfgang von Goethe. pic Games and developed a huge legion of fans. She later moved into films, where  Two Americans are responsible for the major she greatly increased the popularity of her developments in the history of the sport. In 1850, Edward Bushnell of Philadelphia revolutionised sport. skating when he introduced steel-bladed skates allowing complex manoeuvres and turns. Jackson Haines, a ballet master living in Vienna in the Watch the video: 1860s, added elements of ballet and dance to give https://www.youtube.com/watch?v=7sjnfk the sport its grace. EOpsE  Figure skating is the oldest sport on the Olympic Winter Games programme. It was contested at the 1908 London Games and again in 1920 in Antwerp. Men’s, women’s, and pairs were the three events contested until 1972. Since 1976, ice dancing has been the fourth event in the programme, proving a great success. 22

SPORTS SCIENCE STORIES Volume 1, Issue 2 November 2017 2. 2nd General Lyceum of Kamatero Sonja Henie (8 Apr. 1912 – 12 Oct. 1969) was a Norwe- gian-born figure skater and film star. She was a three- time Olympic Champion (1928, 1932, 1936) in Ladies' Singles, a ten-time World Champion (1927-36) and a six- time European Champion (1931-36). Henie won more Olympic and World titles than any other ladies' figure skater. At the height of her acting career, she was one of the highest paid stars in Hollywood and starred in a se- ries of box-office hits, including \"Thin Ice\" (1937), \"My Lucky Star\" (1938), \"Second Fiddle\" (1939) and \"Sun Val- ley Serenade\" (1941). 23

SPORTS SCIENCE STORIES Volume 1, Issue 2 November 2017 3. 2nd General Lyceum of Kamatero 24

SPORTS SCIENCE STORIES Volume 1, Issue 2 November 2017 CHILDREN ICE SKATING ON 2nd General Lyceum 4. THE FROZEN WATERS OF A of Kamatero SCHUYLKILL CANAL ICE SKATING AT THE NATU- RAL HISTORY MUSE- UM, LONDON 25

PHOTOS Volume 1, Issue 2 November 2017 2nd General Lyceum of Kamatero 26

PHOTOS Volume 1, Issue 2 November 2017 2nd General Lyceum of Kamatero 27

PHOTOS Volume 1, Issue 2 November 2017 2nd General Lyceum of Kamatero 28

Figure Skating Spins Volume 1, Issue 2 November 2017 Supervising teachers: Alexandros Markoulakis 2nd General Lyceum Eugenia Potiriadou of Kamatero 29