Water Rocket Extended Essay
Harriet Wehrenberg
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This problem involves two parts. In part one, water is being pushed out and providing an upward thrust. In part two the rocket is in free-fall which is easy to calculate if you don't include friction. In part one the thrust depends on the rate at which water is being ejected. This depends on the size of the nozzle and the pressure inside of the nozzle. This pressure depends on the depth of the water, the acceleration, and the pressure of the air left inside. As the water goes out, the mass of the rocket, the pressure of the air inside (which is undergoing an adiabatic expansion) and the acceleration all change. As Mr. White suggests, you will need a numeric simulation in which the value of each of the many variables is recalculated after each short interval of time (I would suggest starting with every 0.01 sec.). In recent decades I have been doing simulations on an Excel spreadsheet on which formulas are easily propagated and entries are easily changed. Also results can be plotted on a graph. If you can get a reasonable estimate for friction as a function of speed, you may want to also simulate part two.
There's probably no way you are going to be able to come up with a general equation that takes in all the different parameters this situation could have, but you can probably come up with something for a very specific case. That is, where you fix the geometry of the rocket and the surrounding air pressure / air characteristics (wind etc). You can then pick an initial combination of water volume and pressure, shoot off the rocket and record the height. Then you must replicate the experiment at least several times for that combo of water volume/pressure and then repeat the whole thing with a bunch of different combos of water/volume pressure (importantly realizing you cannot assume linearity).
Finally, plot out the data and hope there's a reasonable way to curve fit it. The physics theory should help guide what sorts of equations would reasonably represent this problem, but there are going to be free parameters which have to be found through experimentation described above or very precise computer simulation.
Writing a physics extended essay (EE) can seem like a daunting task, but with the right approach, it can be an enriching and rewarding experience. This article will guide You through the process of writing a physics EE, providing valuable tips and insights along the way.
Before diving into the specifics of writing a physics EE, it is important to understand the criteria that your essay will be assessed on. The criteria for a physics EE are divided into 11 different categories, which collectively add up to a maximum of 36 points. To achieve a high score, it is essential to address each of these criteria effectively. Don't be overwhelmed by the extensive list; by following a structured approach, you can easily fulfill all the requirements.
When selecting a topic for your physics EE, you have three main approaches to consider: experimental, database, and theoretical. While experimental-Based EEs are the most common, don't shy away from exploring database or theoretical ideas if you have a fresh and appropriate concept. Your chosen topic should primarily revolve around physical theories of an appropriate complexity. It is crucial to strike a balance, avoiding topics that are overly advanced and complicated, as it can make it challenging to Delve into the subject matter within the prescribed word limit. Additionally, ensure that your topic has a real-life application and a personal connection to you, as this will enhance the overall quality of your EE.
The research question forms the Core of your physics EE. It should reflect the topic you have chosen and consist of three essential elements: the independent variable, the dependent variable, and the real-life application of your investigation. A good research question follows a clear structure and aligns with the specified criteria. For instance, a research question could be, "How does the maximum Height that a Water rocket can reach change with the variation of the initially filled amount of water?" This question clearly identifies the independent variable (initially filled amount of water), the dependent variable (maximum height), and the real-life application (water rocket). Remember to formulate a research question that is concise, specific, and aligned with the objectives of your EE.
The structure of a physics EE generally follows a standard format. While the exact wording of each section may vary, it is more important to focus on the content rather than the section titles. Nevertheless, it is recommended to maintain a logical order and include the essential elements in each section. The structure typically consists of the following sections:
The abstract is a concise summary of your entire EE, providing a brief overview of the research question, methodology, results, and conclusion. The table of Contents lists all the sections and subsections within your EE, serving as a roadmap for the reader.
The introduction section serves as a comprehensive overview of your research question, explains its significance, and establishes a personal connection to the topic. Here, you will discuss why you chose the topic, its relevance to physics, and its real-life application. Provide the necessary background information and scientific knowledge required for readers to understand the Context of your investigation.
The methodology section outlines and explains your experimental process. It can be presented as a numbered list or in Paragraph form, depending on your supervisor's preference. It is crucial to include a Diagram or picture of your experimental setup, as visual aids enhance the reader's understanding. Additionally, discuss your controlled variables and any safety precautions, if applicable.
In the data collection section, present your quantitative raw data and qualitative observations. Be sure to include only Relevant observations to avoid unnecessarily consuming the word count. Note any measurement uncertainties in your tables and highlight safety hazards or risks involved in your methodology. Measurement uncertainties play a crucial role, so do not overlook them.
This section involves analyzing and processing your data to derive numerical values that address your research question. Graphs, figures, and trend lines should be utilized to present your findings effectively. Your conclusion should directly answer your research question and justify your findings with scientific research. Always refer back to your data and numerical values while explaining your conclusion.
The evaluation section provides an opportunity to discuss the strengths and weaknesses of your methodology. Focus on two solid strengths and weaknesses to avoid diluting the discussion. Propose improvements to your methodology to address the identified weaknesses and discuss possible extensions to your investigation.
These ideas demonstrate that the physics principle underlying your topic does not necessarily have to be within the IB syllabus. However, it is essential to strike a balance, ensuring that the chosen topic is not excessively complicated. By carefully considering these ideas, conducting thorough research, and conducting trial experiments, you can embark on a successful physics EE.
It has lightning bolts on the side and its name is Grease Lightning. Its empty mass is 0.1kg and coefficient of drag is 0.21. The lightning bolts make it faster while the paint job makes it stylish; a perfect combination of aesthetics and performance, I introduce to you our pride and joy, our fast and our furious, our bottle rocket.
Lab 6: Design and test your own water bottle rocket.
Work with a partner to design, build, and test a water rocket with an objective of maximizing the height of trajectory. You may do anything to the bottle except cut into it. The winning team will have the greatest average max height over their two best flights.
10 hours in the lab and it was born. Held together by an indiscernible combination of tape, glue, and more glue, it sat atop my mini-fridge for a long, suspenseful day before its first chance at the launch pad. Will it live up to its name? Will it make it through this day? Only time will tell.
Jesse explains the aerodynamic properties of our rocket. He goes into depth about the streamlined design of the tip to minimize drag, the payload inside the nose and the extended length that shift the center of mass upward to increase stability. He talks about the 120 degree separation of the fins and their careful placement to create maximum rocket stability while minimizing drag, and the rounded leading edge of the fin to gently separate the airflow over its two faces and the sharp trailing edge to bring it back together. He talks about the carefully chosen name and color scheme and how they were NOT indeed the whims of a giggling school girl and the only two colors of spray paint we found in the cabinet.
(Fearing I might intimidate prospective freshmen with the perceived meticulousness of the average MIT student, I feel I must interrupt this blog entry to share with you something much more representative of the typical caliber of my work,
I tried really hard to get a picture of the rocket in its ascent before it left the upper atmosphere but the shutter speed was too long (it was getting quite dark) and it was moving too fast and ended up disappearing in each picture. However, I did get a nice snapshot of it in orbit:
Aww, I remember we made bottle rockets a couple years ago for PREP.
Never did put that attention to the design. In fact, my entire design consisted of cutting apart a cereal box for fins, throwing some pennies in a car funnel, and attaching the whole thing with duct tape. Then spray painting it. Good times, good times.
Nice pictures.