Science Project. Ideal Trajectory of Air Pump Rockets

Transcription

1 Science Project Ideal Trajectory of Air Pump Rockets Physics Lopez Island High School March 3, 2014 Fletcher Moore

2 Abstract This experiment uses model air rockets to test the ideal trajectory a rocket may be launched at to achieve maximum height. We fired multiple rockets at different angles of launch and measured how far each traveled. We then calculated the height each rocket obtained using an equation which involved the time the rocket was in the air and how far it traveled. If this experiment is conducted correctly than it should reflect the most efficient trajectory for all objects (not just these specific air rockets). The purpose of this is to find an optimal angle for launch which would generate the highest altitude. This could be used in everyday life on any object. We found, from this experiment, that an optimal launch angle for maximum height is around 55 degrees. These conclusions were not concrete due to a chance of corrupted data by uncontrollable variables. An important follow up to this experiment would be to see if other objects with different shapes from our air rockets would travel in different ways. This would show us whether the results from the experiment actually apply to everyday life. Introduction This experiment was conducted to find which angle of release would send an air rocket the highest. We conducted this experiment in such a way that we would not be able to immediately observe the results, but rather we would need to collect data and use formulas and calculations to discover the actual numbers. This experiment is interesting because the results we find should apply to all objects and could be applied in real world situations. I think that the rocket which is fired at the highest angle (60 ) will reach the highest altitude. Experimental Write Up Background Information: This lab was conducted during class time as a classroom assignment. The rockets were designed for this use and we were provided with tools suited to measuring this data. The original lab we were assigned was much less involved but I expanded on it for the sake of this extensive write up. Question: At which angle of projection will an air pump rocket meet its maximum height? Hypothesis: The rocket which is launched at the steepest angle (60 ) will reach the highest altitude. This is because less of the kinetic energy of the rocket will be wasted on horizontal motion and will rather be directed upwards. Logical Steps:

3 1. Set up Rocket stand, making sure all components are whole and functional. Carefully select 7 angled wedges with launch degrees of 30, 35, 40, 45, 50, 55 and Select your first angled wedge, place in rocket stand and measure angle with a protractor. 3. Place washer marked low on end of rocket stand. Firmly push rocket onto rocket stand making sure the black plastic washer clicks into place. 4. Attach bicycle pump and ready timer. 5. Pump firmly until the rocket is released. 6. Time the rocket s flight and record. 7. Measure distance rocket traveled and record. 8. Repeat steps 3-7 twice more. 9. Repeat steps 2-8 with the 6 remaining angled wedges. Materials List: Air Rocket and Stand Angled wedges Protractor Measuring wheel Stopwatch Controlled Variables: Same equipment used in each trial. Same pumping technique. Same low power washer used each time Manipulated variable: Angle at which the rocket is launched. Responding Variable: The maximum height the rocket reaches. Validity Measures: All trials were done on the same day with the same weather conditions. Each angle was used and recorded 3 times and an average was used to reduce inaccuracy.

4 Several people participated in the experiment to watch for errors and inaccuracies. Steps for finding data: Calculate horizontal velocity by using the equation: distance/time Calculate vertical velocity by using the equation 4.9(t). We came to this equation by simplifying the pervious equation. Now that you have vertical velocity you can solve for height. To do this you must substitute t (time) for ½t in the equation. Our final equation was, Yf=-4.9 (½ t) 2 +Viy( ½ t)+ Yi Degree of Launch Average Distance (meters) Average Time (seconds) Data Table Horizontal Acceleratio n (m/s 2 ) Vertical Acceleratio n (m/s 2 ) Overall Velocity (m/s) Max Height (meters)

5 Max Height (meters) Average Distance (meters) Average Distance (seconds) Graphs of Results Horizontal DIstance Time Degree of Launch Height Degree of Launch Degree of Launch Conclusion: The rocket achieved it maximum height of almost 24 meters when launched at an angle of 55 degrees while the rocket launched at 60 degrees reached a height of 22.4 meters. The rockets which were shot at a higher angle were consistently higher than the others even though the absolute steepest did not gain the most altitude there may be some factors which could have contributed to that. There may have been a slight tailwind during trials, which could have slightly lifted the rocket, when fired at a slightly lower angle such as 55 degrees, giving it a small advantage in maximum height.

6 Discussion This experiment went very smoothly and the rockets performed flawlessly. We were able to accurately record all of our launches while doing everything possible to make sure they were consistent. However there were several things which could have gone wrong with the rockets and environment. There may have been a wind which arose during our experiment which could have created a variable between the separate launches. Another factor which could have caused inaccurate results could have been based on the rockets themselves. To set up the rocket to fire you must force the washer onto the end of the rocket stand until it clicks on. However after many launches, this washer may have become looser and therefore easier to detach. This would have given later launches less power than the ones before them I did not see any evidence of these kinds of incidents taking place but they are possibilities in this experiment. This experiment gave us a good idea of what angle objects can travel the highest at. However there are follow up experiments which could solidify our results. One example would be to conduct a similar experiment but using different objects. This would show us how different shapes react to different angles of launch. This experiment would be difficult because rockets are designed to fly straight and steady while most other objects are not. This experiment got straight to the core of my original question and hypothesis. I was able to fully address what I intended to at the beginning. We controlled the experiment to the best of our ability and came out with successful results. My hypothesis was not entirely correct but I was right in my general idea. I thought that the higher the angle of release the greater the altitude of the rocket. The data did follow this trend but it showed that the rocket gained the highest altitude at 55 degrees instead of 60, (which was the highest.) This could have been due to how the rockets and launchers are designed or the specific parameters of the experiment. I still believe that a higher launch angle will give the greatest altitude even if this experiment did not show those results.