Styro-Geyser. April 26, Chris Dunn, Alex Lewis, John Mullen, Michael Swift

Transcription

1 Styro-Geyser April 26, 2009 Chris Dunn, Alex Lewis, John Mullen, Michael Swift

2 Abstract ii The Styro-Geyser was an ingenious Rube Goldberg device built by Chris Dunn, Alex Lewis, John Mullen, and Michael Swift. The device was composed of several simple steps which ultimately turned on a electric fan and levitate a Styrofoam ball. It was build from readily available materials in Estrabrook 13 and from materials bought at Lowe s. Several major conclusions were found including the value of teamwork and the application of physical concepts to actual experiments.

3 1 Introduction A Rube Goldberg device is a deliberately over engineered apparatus that performs a very simple task in a very complex fashion, usually by a chain reaction. The goal is to incorporate several smaller simple processes together. The purpose of Team Project 3 for Engineering Fundamentals 151 was to build a Rube Goldberg device, under the following guidelines of four objectives: 1) Solve an open-ended problem while working and emphasizing teamwork. 2) Demonstrate and practice ways that engineers communicate presentations, spreadsheets, and written reports. 3) Apply physical principles learned and covered in Engineering Fundamentals 151 and Engineering Fundamentals ) Most importantly, have fun Design Process The criteria for the device required that the project have at least five different steps. Next, the device had to operate without interaction of manipulation once started. Also, the device was supposed to operate an electrical device. Therefore, the group decided to involve the following four principles of engineering: 1) Conservation of Energy (including potential, kinetic rotational, and kinetic translational) 2) Conservation of Linear Momentum (collusion) 3) Torque (rotational motion) 4) Center of Mass (balancing an object) Device Description The Styro-Geyser consisted of six basic materials that can be found at any hardware store. 1) PVC Piping (no direct cost to the team since it was acquired from Estrabrook 13) 2) Pine Wood (no direct cost to the team, it was found in Estrabrook and at a team member s home) 3) Electrical Fan ($9.00 from Lowe s) 4) Light Switch ($2.25 from Lowe s) 5) Copper wiring (from Lowe s, but was not charged since a minute amount was used) 6) Various screws, nails, pieces of metal, Styrofoam balls, and miscellaneous objects ($5.00 from Lowe s)

4 2 Using these materials, an overview plan on how the device should work and operate was discussed and devised. The Styro-Geyser is instigated by a falling weight (3, D-Cell batteries) that is released from a hinged joint. This weight causes a pair of scissors to cut a string that is strung across two parallel pieces of wood. After the string is cut, a PVC pipe is released. The swinging PVC pipe lunges forward, contacting a balanced weighted spool. The spool then accelerates down a wooden 12 inclined ramp striking, flipping, and turning on the light switch. This light switch is connected to an electric fan with copper wiring. The flipped switch created a closed circuit, which then caused the fan to begin rotating, funneling air into a tall PVC pipe. The airflow caused a Styrofoam ball on the inside to elevate and levitate at the top of the pipe. Results of Testing After the construction of the Styro-Geyser was complete, the only object missing was the ball to used in the grand finale. The initial test was to see how powerful the fan really was and how dense of a ball it could support. To do this, three different balls were used: golf, ping-pong, and Styrofoam. Testing the golf ball first, it was quickly realized that the fan lacked the power to elevate it let alone cause it to float. Next, the ping-pong ball was tested. The fan caused it to elevate but not fully leave the PVC piping. Not wanting to cut the pipe down anymore, the Styrofoam ball was tested and ultimately selected since the fan provided sufficient power to elevate and levitate it. Excited with this unexpected development, the Styro-Geyser, the Styro-Geyser was fully tested for the first time, and it worked perfectly. Conclusions The Styro-Geyser was a successful Rube Goldberg device. It never failed in any of the test runs. The device also performed nicely the first time during the Engineering Fundamentals 151 presentations. The device lasted for six seconds and had five total steps, meeting the required amount. In the team s opinion, the Styro-Geyser was inefficient and complicated, and clearly demonstrated the creative teamwork. The only and primary obstacle stemmed from rewiring the fan so that the light switch would turn the fan on and off. This was solved by cutting and soldering copper wire to the fan and then wrapping it around the light switch to create a circuit. If anything could have done anything differently in the design of the device, it would have involved fire in some way, shape, or form. The only reason fire was not chosen for the Styro-Geyser was because Professor Schleter had forbidden fire, explosions, sharp projectiles, high-speed, etc. He and Dr. Arazi wanted all of the Rube Goldberg devices to operate in a safe, clean, and non-destructive manner. Also, teamwork and physical concepts were reinforced and applied thus strengthening both the understanding and practice of teamwork and physical concepts. Appendices

5 The initial exposition of conservation of energy occurred at the falling weight. 3 mgh = ½ mv 2 using the values from the experiment: (2.5lbs)(.708ft)= 1/2(2.5/32.2)v 2 solving for final velocity, it was determined to be 6.75 ft/s. The next calculation was the torque of the swinging PVC. Solving for torque using the equation τ = Frsin where F=(.667lbs), r = (.917ft), and = 130, it was found to be.468ft-lbs. The swinging PVC also demonstrated conservation of energy by: mgh= 1/2 mv 2 + 1/2I 2. Plugging in the values it was discovered the ideal velocity of the was equal to (.25lbs +.31lbs)(4.5/12 ft) = 1/2(.25lbs +.31lbs)v 2 + 1/2(1/3(.25lbs/32.2ft/s 2 )(.91667ft) 2 + (.33lbs/32.2ft/s 2 )(1.1ft) 2 (v 2 /1.1ft 2 ). Solving for velocity, it was found that the pipe swung at.844ft/s. Once the pipe comes into contact with the balanced spool conservation of momentum is displayed. The equation mvd=m v can be used to solve for the velocity of the spool, which is necessary to solve for the final velocity of the spool whenever it reaches the bottom of the ramp. The mass of the pipe is (.25lbs +.33 lbs)/(32.2 ft/s 2 ). The initial velocity that was solved for previously by using conservation of energy with regard to the pipe was (.844 ft/s). The distance was (.125ft) and the mass of the spool on was measured to be (.5lbs)/(32.2 ft/s 2 ). Therefore, the velocity was solved for and determined to be.1224 ft/s. Finally, conservation of energy was solved for in the spool using mgh + 1/2mv 2 + 1/2I 2 = 1/2mv 2 + 1/2I 2 where the initial velocity was (.1224 ft/s), h=(.708sin12 ft) and every other unit canceled and was arbitrary. The final velocity equaled to 2.61 ft/s.