Abstract

Objective

The goal of this sports science fair project is to investigate the effect of speed on the distance and height of the skateboarding trick "the ollie."

Introduction

Skateboarding is a sport that requires skill, fearlessness, and years of practice. Many skateboarders are passionate about their sport and consider it an art form. The skateboard is a simple piece of equipment. It is composed of three parts: (1) the board, (2) the wheels, and (3) the trucks, which connect the wheels to the board. It is amazing to see a skateboarder riding down the street without running into things and jumping over obstacles, such as sidewalks and staircases. What is really cool to watch is when they jump over obstacles—the board seems to stick to the skater's feet in midair. This trick is called an ollie (after Alan "Ollie" Gelfand) and it is the basis of more-complicated skateboarding tricks. But how does a skater perform this trick? Shouldn't the board fall to the ground, along with the skater? Isn't that how gravity works? Let's learn more about this trick.

There are three forces that come into play as the skateboarder rides forward on his or her skateboard. These forces are the weight of the rider pressing down on the board, the effect of gravity pulling down on the rider, and the forces of the ground pushing up. When a skateboarder decides to perform an ollie, the first step is to crouch down slightly. This helps the skateboarder jump and accelerate upward. Then the skateboarder presses down with his or her rear foot, sharply, on the tail of skateboard. This causes the skateboard to flip up counterclockwise or clockwise, depending on in which direction the skateboarder is travelling. The ground pushes back against the board and causes it to rotate clockwise or counterclockwise. As the board is rotating, the skater drags his or her forward foot up along the board. This pulls the board higher up. The skater then pushes down with his or her forward foot on the front of the board, while pulling up on his or her rear foot to get out of the way of the rotating board. The skater and the board are level at this point and look stuck together. Finally, gravity takes over and pulls the skater and the board back to the ground.

In this sports science fair project, you will investigate whether a skateboarder's initial speed affects the length and height of the ollie. See how high the experienced skateboarder (you, or someone you know) can go, and how far he or she can jump! Maybe over a soda can or over a curb? Who knows? Once you've figured out the physics of skateboarding, and with a few years of practice, maybe you could be the next Tony Hawk or Danny Way—executing 900s, 360 flips, and jumping over the Great Wall of China!

Terms, Concepts, and Questions to Start Background Research

• Ollie
• Gravity
• Force
• Acceleration
• Speed

Questions

• What are the parts of a typical skateboard?
• How are the wheels, trucks, and board connected and how does it all work together to allow the skateboarder to turn?
• What skateboard tricks have ollies in them?
• What are the forces that affect the skateboarder as he or she rides?

Bibliography

• The Exploratorium. (n.d.). Skateboard Science. Retrieved May 12, 2009, from http://www.exploratorium.edu/skateboarding/
• Tesler, P. (2007, May 4). Physical. Current Science. Retrieved July 31, 2009, from http://www.dannyway.com/_press/PhysicsOfSkating.pdf

The following website belongs a well-known professional skateboarder, Tony Hawk, which has videos that show him performing very complicated tricks, like the 900.

• Hawk, T. (2009). Tony Hawk: Official Website. Retrieved May 12, 2009, from http://www.tonyhawk.com/index.html

For help creating graphs, try this website:

• National Center for Education Statistics. (n.d.). Create a Graph. Retrieved May 12, 2009, from http://nces.ed.gov/nceskids/CreateAGraph/default.aspx

Materials and Equipment

• Large area that is free from pedestrian and automobile traffic. The skateboarder needs to skate near a wall or a landmark so that you can use it to make marks and observations.
• Digital video camera
• Tripod that fits the video camera
• Meterstick
• Chalk of various colors
• Volunteers (2, in addition to you). One person will perform the ollies, one will videotape the ollies, and another person will help to mark the length and height of the jumps. You might want an adult who is familiar with the digital video camera to record the ollies.
• Stopwatch
• Lab notebook
• Graph paper

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Experimental Procedure

Important Notes:

• You, or someone you know, must own a skateboard and safety equipment, and know how to skateboard to perform the ollie trick.
• All safety equipment must be worn by the person performing the ollie.
• You should perform the tests in a skateboard park or in a large area where it is legal and safe to skateboard.

Setting Up the Experiment

1. Set up the area where you will be doing the ollies for the science fair project.
   1. Use the chalk to make a mark on the ground where the ollie will start. Use the meterstick and make chalk marks on the ground every ½ meter (m) for 5 m.
   2. Make chalk marks on the wall to determine the height of the ollie. Use the meterstick and make the marks every 1/4 m, starting from the ground. Clearly label each mark with its height from the ground.
   3. Find a good spot for the observer volunteer to observe the ollies. He or she shouldn't get in the way, but needs to be able to see how high and how far the person performing the ollie goes.
2. The volunteer who will be recording the ollies should know how to operate the digital video camera. Find a good spot for this volunteer to stand and videotape. The volunteer needs to capture the person skating and performing the ollie in front of the wall. Place the tripod on the correct spot and attach the camera to the tripod. Adjust the video camera so that you can use it to determine the height of the jump. Make sure that you can see the numbers on the wall clearly on the video camera. The volunteer who is videotaping must be positioned a little bit past the mark on the ground where the person will be starting the ollie.
3. The person performing the ollie should put on the helmet, the elbow pads, and the knee pads. The person should get on the skateboard and warm up—skate around and make sure that he or she feels comfortable and ready. Make sure that the other two volunteers are ready to make their observations and that the video camera is ready to record.

Testing

1. Place the front of the skateboard on the chalk mark that you drew on the ground. The first ollie will be performed at zero speed; in other words, in the spot on which the person is standing. The stopwatch is not needed in this step.
2. Have the person pop the ollie. The volunteer who is observing how far the person jumps should note the location of the front of the skateboard when it lands. Use the meterstick to measure the distance. Record the length of the ollie in your lab notebook in a data table, like the one shown below.

3. Rewind the video and read the height of the ollie from the recording. Record this height in the data table and then fast-forward the video to where the ollie ended.
4. To reduce error in you measurements, repeat steps 1–3 two more times. Always record the data in your lab notebook. Redraw the marks on the ground with chalk, if necessary.
5. Now take the skateboard 5 m away from the marks on the ground. Have the observer volunteer use the stopwatch to time how long it takes for the person skateboarding to get to the first mark on the ground. They should start the stopwatch when the person starts to ride, and stop the stopwatch when the person pops the ollie at the first mark on the ground. Make sure that the other volunteer is video taping. The person should ride toward the first mark on the ground at a medium speed. When the front of the board gets to the first mark on ground, he or she should pop an ollie. Have the observer volunteer use the chalk to mark the location of the front of the board when it hits the ground. Measure the distance from the first mark where the person popped the ollie to the landing mark. Record this data, along with the time on the stopwatch, in your lab notebook.
6. Rewind the video and read the height of the ollie from the recording. Record this height in the data table and then fast-forward the video to where the last ollie ended.
7. Divide the distance that the person rode to the first mark by the time that it took to get there (the time from the stopwatch). This is the speed that the skateboarder was going when he or she popped the ollie. Record the speed in your lab notebook.
8. To reduce error in your measurements, repeat steps 5–7 two more times. Have the person skateboarding try to move at the same speed at which he or she rode the first time. Record all data in your lab notebook.
9. Now repeat steps 5–8, except have the skateboarder go as fast as he or she can, or at least increase his or her speed over the last three trials. Record all data in your lab notebook. In the end, you should have a total of at least 9 trials (3 for each speed).

Analyzing the Data.

1. Average the length and height data for each of the three speeds. Record this data in a table like, the one shown below.

2. Graph the data. You can graph the data by hand or if you have questions about graphing, or would like to make your graphs online, visit the following website: Create a Graph. Make two graphs. For the first graph label the x-axis Speed and the y-axis Average Ollie Length. For the second graph label the x-axis Speed and the y-axis Average Ollie Height. How does speed affect the length of the ollie and the height of the ollie?

Variations

• Can you improve upon the procedure? Are there other variables that are affected by speed?
• Using a timer function in the digital camera, record the time that you are in flight during an ollie. Is the time of flight dependent on speed?
• How does the shape of the skateboard affect ollie length and height? Do the experiment and find out.
• Add a kick flip to the ollie. How does this affect the height and length of the trick?
• If you are really into skateboarding, try another Science Buddies skateboarding science fair project, Skateboard Extremes: Which Wheels are Best for Speed & Turns?

• For more science project ideas in this area of science, see Sports Science Project Ideas.

Credits

Michelle Maranowski, PhD, Science Buddies

Special thanks to Jonathan Perez and Circle-A Skateboards in San Jose, California for advice and help testing this project.

Last edit date: 2009-07-08 10:17:00