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 →
Kinetic Energy →
  1. Describe when potential and kinetic energy are at their highest in the halfpipe.

Potential Energy →
Kinetic Energy →
  1. Why did skateboarding begin?
  1. What force acts against the skateboard and slows skaters down?

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.

START THE SIMULATION:

Click on Run Now (Green button)

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?

Turn on the pie chart and the bar graph.

  1. 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?
  1. 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?
  1. Watching the bar graph…what general statement can you make about the relationship between KE and PE?

Tools

  1. What color represents potential energy and which is kinetic energy? What does the color orange represent?
  1. What determines the Thermal energy pie section? What rules does it seem to follow?
  1. What determines the Potential energy pie section? What rule(s) does it seem to follow?
  1. What determines the Kinetic energy pie section? What rules does it seem to follow?
  1. Click on Bar Graph on the tool panel. What does the bar graph show? What rules does it follow?
  1. 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?
  1. 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
Uphill
  1. As an object moves down the track, the kinetic energy ______and the potential energy ______. When the object moves up the track the kinetic energy ______and the potential energy ______.
  1. 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.

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?).

  1. What do you think conservation of energy means?
  1. Explain which visual aid (the pie, energy vs. position, or bar graph) helps you understand conservation of energy better, and why.
  1. 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?

PART C: Adding Friction

  1. Reset the simulation.
  2. Open the bar graph again
  3. Click “Track Friction.”
  4. Move the slider to change the friction
  1. 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
Uphill
  1. As an object moves down the track, the kinetic energy ______and the potential energy ______. The total energy ______.
  1. 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.
  1. Complete the observation statement:
  2. As the skater moves with friction, the kinetic energy and potential energy both ______, the thermal energy______and the total energy ______.
  1. Write a possible explanation for this.
  1. Discuss what changed and what stayed the same when friction was added to the skate park .
  1. 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.

CONCLUSION

  1. Write a full paragraph explaining what affects the relationship between potential and kinetic energy as well as what the conservation of energy is.

PARAGRAPH WILL VARY

Key Points Include

  • PE is stored energy due to its position
  • KE is energy due to motion
  • PE transforms into KE as the skater moves down the hill
  • The faster the skater, the greater the kinetic energy
  • As the skater moves up the hill, the KE is transformed into PE
  • The total energy stays the same throughout the entire motion
  • Energy is neither created nor destroyed only transformed back and forth between KE and PE

PART D: CREATING A SKATE PARK

Thanks to your great skateboarding skills, city officials have asked you to add your expertise with designing a new skate park. Experiment with the different tracks that are available under the tracks icon at the top of the page and build your idea of the perfect track. Draw your track below. If your first track did not work (skater got stuck or fell off), design another track and explain why your first idea didn’t work. How can you use what you know about kinetic and potential energy to help you with your designs? Take a picture of your final track and insert here!

JFF – Just for fun (IF YOU FINISH EARLY!!)

  1. See if you can have the skater do two loops. Draw your track.
  1. See if you can have the skater go airborne, but land on another track.