Propulsion Power! Which will Move a Wooden Car 10 Feet in the Shortest Time, Fan Power, Soda and Mentos or Rocket Propulsion?

Research Questions:

• What is propulsion power? 
• What is Newton`s Third Law of Motion? 
• What are common fuels? 
• What is momentum? 
• What is an exothermic reaction? 
• What are the different sources of energy for propulsion power? 
• What are the intervening variables in this project? 
• Soda and Mentos, how are they combined? Is this a safe combination? Are there safety
• precautions to be taken in combining these two substances?

On the information level, this experiment serves to acquaint students with basic and current information on the process of propulsion. Propulsion is the process of causing a body to move by exerting a force against it. It is based on Newton`s Third Law of Motion namely that every action has an equal and an opposite reaction. Stated in terms of momentum, the law states that the force applied to any body is equal to the rate of change of momentum of that body and is exerted in the same direction as the change of momentum. However, it is obvious that a key factor is the medium in which the vehicle is traveling, be it air or water. To produce momentum and propulsion, we require an energy source. The most common energy source is heat generated by the combustion of exothermic chemical reactions. These yield heat. Another source of energy is nuclear energy and a third source is aerodynamic force. Still another source is propellants as in rockets. In this project, we have three contestants to produce the greatest momentum. Keep in mind that momentum is defined as the product of a body`s mass and velocity. Your task is to discover which one, the action of the fan, the chemical reaction of the coke and mentos (peppermint) or the rocket power will provide the maximum momentum in the shortest period of time.

This science fair experiment also serves to acquaint students with the essential processes of sciencing such as the importance of the use of a control, of identifying dependent and independent variables, of data collection, of pictorial and or graphic presentation of data and of being able to make better judgments as to the validity and reliability of their findings. They take on the role of scientists and in the process they learn to act as one.

Materials:

• a car made from wooden blocks
• 3 large diet coke cola
• a package of mentos 
• a rocket kit
• a fan car assembly kit
• a stopwatch
• a plastic marker 
• string
• nails
• tap
• meter stick
• a tool kit

These are readily available at the local hardware store and hobby store. Some are available from home.

Experimental Procedure:

1. Gather all the materials you will need for this project. These include: a car made from wooden blocks,3 large diet cokes, a package of mentos , a rocket kit, a fan car assembly kit , a stopwatch, a plastic marker , string, nails, tap, measuring stick and a tool kit. Do not forget your safety glasses, apron and gloves. You may wish to take photos of the experiment so include a camera. In addition, you can also photograph the processes of constructing the rocket, the fan and the car.
2. Copy the Data Chart so that you can readily record your findings.
3. Prepare and state your hypothesis. Based on your armchair research, which of the methods of propulsion will provide the greatest and most rapid momentum? In short, the winner will be?
4.  You will begin by assembling all of the “props” you require using each of the three kits and following the specific enclosed directions. You will construct a car, a rocket to be attached to the car and a fan assembly to be attached to the car. Wear your safety glasses.
5. Now, select your road and measure the 10 foot distance the car will travel in each of the trials you will make using each of the sources of propulsion power, the fan, the rocket and the chemical reaction of mentos and coke.
6. Begin with the fan; make two trials, record the time it took to reach the finish line.
7. Now attach the rocket to the car and again, make two trials and record the time it took to reach the finish line. Record your findings. Wear your safety glasses and apron and gloves.
8. Now combine the mentors and the coke and observe the effect of the resultant pressure on your car and again record the time it took to move 10 feet. Two trials! Record your findings.
9. Review the data. Average your findings. What are your conclusions? And the winner is ___!
10. Write up your final report. Include the research, the data, and the photos. Do not forget your bibliography. You may want to include some statement as to what you view as practical applications of your research as well as how you felt about doing this project.

                                                      The Data Chart of Observations

Terms/Concepts: Power, propulsion power, force, fluids, fuels, energy, Newton`s Third Law of Motion, momentum, velocity, aerodynamic force, fuel consumption, turbine propulsion ,nuclear energy and exothermic reactions.

References:

McGraw-Hill Concise Encyclopedia of Engineering. © 2002 by The McGraw-Hill Companies, Inc.