Adventures in Energy Skate Park Lab

Adventures in Energy Skate Park Skateboarding has seen an immense growth in popularity over the last several years. What started as a way for surfers to kill time when the waves were not high enough for surfing has turned into an organized, competitive sport that boasts internationally known athletes and a million dollar industry. One way physics comes into play in the halfpipe is with the principle of conservation of energy. This principle states that energy cannot be added or subtracted from the original energy of a system. Energy can, however, be transformed, between forms. The primary forms of energy that skaters experience in the half pipe are potential energy and kinetic energy. Potential energy is stored energy that is related to height. When skaters are at the tops of the ramps, they have the highest amount of potential energy. Kinetic energy is energy of motion. The faster skaters move, the more kinetic energy they have. In a halfpipe, energy is constantly transformed between potential (at the top) and kinetic (as they travel down the sides) as the skater goes back and forth between the ramps. However, they cannot continue this movement forever, due to the force of friction which acts against skaters, causing them to slow down unless they apply more force to their movements. Read the text above to answer questions 1-4: 1. Define potential and kinetic energy. Potential Energy → stored energy Kinetic Energy → energy of motion 2. Describe when potential and kinetic energy are at their highest in the halfpipe. Potential Energy → at the top of the pipe Kinetic Energy → at the bottom of the half pipe 3. Why did skateboarding begin? For surfers to practice when the waves were not high enough. 4. What force acts against the skateboard and slows skaters down? Gravity and friction THE LAB ACTIVITY Purpose – The purpose of the energy skate park simulation is to see how energy gets transferred in a real world application. In this simulation you will manipulate the skater and track to determine how it affects the energy of the system. In our skate park, there is no friction until part C, so you will not be dealing with that factor. PART A: Exploring the Skate Park In the next 10 minutes, explore the simulation with your partner and complete the following checklist: 1. Move the blue dots on the track and run the skater. 2. Try out different locations. 3. Try different skaters. 4. Try the different energy graphs. 5. Add friction to a track. PART B: Exploring Conservation of Energy RESET THE SIMULATION. Observe the movements of the skater in the half pipe. 1. Does the skater hit the same height on the opposite sides of the track? Is this realistic? The skater does hit the same height on the opposite side of the track but this is not realistic because friction is not taken into account. Turn on the pie chart and the bar graph. 2. Watch what happens to the PE as the skater is higher on the track. What is the relationship between the PE and the height of the skater on the track? PE increases as the skater gets higher on the track. 3. Watch what happens to the KE as the skater moves faster and slower on the track. He is slowest at the top of the track just before he reverses direction and fastest at the bottom of the bend. What is the relationship between the KE and the speed of the skater on the track? KE gets higher as the speed is faster. 4. Watching the bar graph…what general statement can you make about the relationship between KE and PE? As PE increases KE decreases and vice versa. Tools 1. What color represents potential energy and which is kinetic energy? What does the color orange represent? PE is blue, KE is green, and the orange is thermal energy. 2. What determines the Thermal energy pie section? What rules does it seem to follow? Thermal energy happens when the skater hits the track or the ground --- collision! 3. What determines the Potential energy pie section? What rule(s) does it seem to follow? Potential energy is determined by how far above the ground the skater is. The higher up, the more potential energy. 4. What determines the Kinetic energy pie section? What rules does it seem to follow? Kinetic energy is determined by how fast the skater is moving. The faster a skater moves, the more kinetic energy he has. 5. Click on Bar Graph on the tool panel. What does the bar graph show? What rules does it follow? The bar graph shows KE, PE, TE and total energy. The PE and KE “switch places.” Thermal energy only shows up if the skater hits the track or ground. But the total energy is the same at all times--- it is the KE + PE + TE. 6. When does the skater have the highest amount of kinetic energy? Potential energy? When does the skater have the lowest amount of kinetic energy? Potential energy? KE is highest at the bottom of the ramp. PE is the highest at the top of the ramp and vice versa. 7. Fill out the table below. Is the energy increasing, decreasing, or staying the same? Skater’s Movement Image Potential Energy Kinetic Energy Total Energy Downhill D I S Uphill I D S 8. As an object moves down the track, the kinetic energy ___increases______ and the potential energy __decreases_________. When the object moves up the track the kinetic energy ___decreases_____ and the potential energy ___increases____. 9. Look at your data table and focus on the Total energy column. Write a statement or two about the “total energy” of the object moving up and down the track. The total energy is always the same. It is the sum of the potential energy and the kinetic energy. 10. Describe how the bar graph changes as the skater moves along the track (i.e. what happens when the skater is high on the track? Low on the track?). KE increases as he goes down the ramp and the PE increases as he goes up the ramp. 11. What do you think conservation of energy means? Energy is neither created nor destroyed only transformed in this case from PE to KE and back! 12. Explain which visual aid (the pie, energy vs. position, or bar graph) helps you understand conservat≠ion of energy better, and why. Answers will vary... The bar graph worked best for me because you can see the height of the PE and KE bars would add to the total bar and the total bar does not change at all --- energy is transformed but not lost. 13. What general rule about the hills do you have to follow to get the skater to go all the way from one side of your track to the other? What can affect whether it works or not? The hill can not be higher than the starting point. PART C: Adding Friction 1. Reset the simulation. a. Open the bar graph again b. Click “Track Friction.” c. Move the slider to change the friction 2. Fill out the table below. Is the energy increasing, decreasing, or staying the same? Skater’s Movement Potential Energy Kinetic Energy Total Energy THERMAL ENERGY Downhill D I S I Uphill I D S I I 3. As an object moves down the track, the kinetic energy ___increases______ and the potential energy ___decreases_________. The total energy ____stays the same______________. 4. After watching the bar graph while the object is moving, especially with “lots” of friction, write a title for the last column. Fill in the last column. 5. Complete the observation statement: a. As the skater moves with friction, the kinetic energy and potential energy both _decrease__, the thermal energy___increases_____ and the total energy ___stays the same_____. 6. Write a possible explanation for this. The friction causes thermal energy. Some of the kinetic energy is transformed into thermal energy and then there is less to move the skater back up the ramp giving them less potential energy. 7. Discuss what changed and what stayed the same when friction was added to the skate park . The total energy still stayed the same but as time went on the PE and KE decreased from the beginning and the TE increased. Eventually the skater stopped moving and all that was left was a little PE because he was above the ground and a lot of thermal. 8. Which situation, with friction or without friction, is more similar to your everyday experience on a skateboard or bicycle? Write at least 2 sentences to explain your answer. When I ride a bike there is friction between the tires and the road. If I were to coast down a hill I could not make it back up to the corresponding side of the other hill. Friction would be “slowing” me down.