Science of NHL Hockey: Kinematics Subject Area: Physics, Math Grade Level: 9–12 (Physics) Lesson Title: Kinematics National Science Education Standards Science as Inquiry: 9–12 Motions and Forces: 9–12 Suggested Prior Knowledge definition of speed; definition of constant acceleration; use of stopwatch and measuring tape or meter stick Purpose and Introduction: This video focuses on the motion of individual hockey players, making the relationship to science concepts of speed, velocity, and acceleration. The activity enables students to understand the basics of kinematics and to measure speed and acceleration with simple equipment. Key Vocabulary: acceleration—change in velocity over time; either a change in speed or a change in the direction of motion. kinematics—description of the motion of objects without consideration of the causes of the motion. position—the location of an object in space. velocity—the change of an object’s position over time. Objectives: 1. Students will design and carry out an investigation to measure acceleration. 2. Students will determine the relation between distance and constant acceleration. 3. Students will determine the dependence of acceleration on the inclination of a ramp. Materials: - safety goggles - hard rubber ball (if available, a hockey puck for a visual connection) - grooved track 1 m long (if unavailable, substitute a board with cardboard taped to the end to create a ramp) - two books of the same thickness - measuring tape or meter stick - stopwatch Procedure: 1. Review with students the definitions of speed and velocity. Remind them how time, distance, and speed are related. Summarize the discussion of acceleration in the video. Speed and acceleration are crucial for players in hockey (and other sports, such as basketball, soccer, lacrosse and jai alai). Speed and acceleration are also vital to moving the puck (or a ball, in other sports). Make sure students recognize acceleration can be either a change in speed or a change in direction. 2. Discuss with students how they can design an experiment to measure acceleration. Begin with a leading question such as How can you describe the motion of a moving hockey puck? Then guide discussion with questions such as the following: What kind of acceleration does a falling puck undergo? How can you slow down this acceleration so that it is easier to study? What equipment is necessary to measure the acceleration? How can you vary the rate of acceleration? What is the formula for the distance traveled by an accelerating body? 3. Lab protocols should be followed, incorporating safety equipment. Goggles must be worn at all times. 4. The basic procedure suggested here is to measure the time a ball takes to roll several distances down a track. From their measurements, students should be able to find a quadratic equation relating time and distance. However, students may prefer to construct another activity using these materials. For instance, they may choose to measure the speed of the ball at the bottom of the track and relate that speed to the time spent accelerating down the track. Encourage students to think of other ways to measure acceleration. 5. If students need prompting, suggest they begin by propping up one end of a track with a single book. Then measure the time the ball takes to roll a fixed distance down the track. Encourage students to increase accuracy by measuring the time more than once for each distance and averaging the measurements. 6. After students measure times for a few distances, they should graph distance vs. time and distance vs. (time)2. (Distances such as 5 cm, 20 cm, 45 cm, and 80 cm are convenient to work with, but students may not recognize this.) The second graph should show a straight line, and students can calculate the acceleration using the formula d = 0.5at2. Data Angle of Track (degrees) Distance Down Track (meters) Time to Bottom of Track (seconds) Average Speed on Track (m/s) 7. Students could then increase the inclination of the track and repeat the procedure, measuring the times for the same distances as in the first part of the procedure. When the track is propped up with two books, the acceleration should be twice that measured for a single book. 8. Revisit the video to make connections between the aspects of kinematics of the balls on the track and the hockey players on the ice. Have students compare their graphs and calculations to those in the video. 9. To conclude the activity, ask students to think about a hockey player skating in a circle at a constant speed. Is the velocity of the player constant? How do you know? Is the acceleration of the hockey player constant? How do you know? If student are familiar with vectors, show them the diagram below for an object that moves in a circle with constant speed v. Have them sketch the acceleration represented by the change in velocity between point A and point B. (If necessary, review vector addition). Ask how it would compare to the acceleration acting between point C and point D. Ask what the direction is of the acceleration of the body at any point on the circle. Figure 1 Additional Resources: http://www.physics.ucla.edu/demoweb/demomanual/mechanics/kinematics/accele ration_down_an_inclined_plane.html http://www.utm.edu/departments/cece/cesme/psam/PSAM/psam17.pdf http://www.quora.com/What-is-the-maximum-speed-ice-hockey-players-reach http://www.real-world-physics-problems.com/physics-of-hockey.html http://www.hockeyplayer.com/paid/publish/article_359.shtml http://www.laurastamm.net/Power-Skating-Crossovers.aspx Student Worksheet for Kinematics Experiment Title: _____________________________Date: __________Name: _____________ Student Question or Hypothesis: ____________________________________________________________________________ Materials: - safety goggles - hard rubber ball (if available, a hockey puck) - grooved track 1 m long (if unavailable, substitute a board with cardboard taped to the end to create a ramp) - two books of the same thickness - measuring tape or meter stick - stopwatch Safety Concerns: _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ Procedure: ____________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ Data: Observations: __________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ Analysis of Data: _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ Conclusion: ___________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________