Bicycle Aerodynamics by S.E. Cossey Mr. Cossey period x September 20, 2000

Title:Quest for Speed Purpose: To determine if lowering your body position while going downhill on a bicycle can actually improve your speed Which is faster? upright or tucked Hypothesis: A rider coasting downhill in a tucked position will reach a higher speed than if the rider remained upright

Materials: A long yards) a bicycle, a timer, a bike, start and finish markers and a rider(with helmet) Independent Variable: the rider’s body position on the bicycle (upright or crouched) Dependent Variable: the time it takes to go down the hill Constants: use same bike, same rider, follow same path, run all trials on the same day, hold same body position

Control: Compare course times for the upright position with the times for the crouched position Procedure: Mark the start and finish points for the course. From a still position lift foot and begin descent. Start timer the instant foot is off the ground. Follow same path down the course. Maintain same body position (either upright or tucked) for entire length of course. Stop timer the instant the end point is passed. Record data.

Data:

Conclusion: The data I collected supports my hypothesis that an aerodynamic body position will help increase downhill speed on a bicycle. On average my rider finished the course a full 2 seconds faster while in a crouched position.

How come this rider was not allowed to do some of the trial runs in the experiment? List as many reasons as you can.