Physics EE (Extended Essay) on Bicycle Stability

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Discussion Overview

The discussion centers around an IB student's extended essay (EE) on the stability of bicycles, exploring various factors that influence this stability. The scope includes theoretical considerations and experimental design related to bicycle dynamics, particularly with and without a rider.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant suggests measuring how long a bicycle can remain upright, clarifying that this should be done while rolling, not standing still.
  • Some participants propose that studying bicycle stability with a rider is more relevant due to the practical application of bicycles in use.
  • Concerns are raised about human error when including a rider, which may affect the consistency of trials.
  • Various factors are proposed for investigation, including air pressure in the tires, weight distribution, and fork angle, among others, with some participants emphasizing the need for factors that are measurable yet not straightforward.
  • Links to previous discussions on bicycle stability and related topics are shared for additional context and resources.
  • References to literature, such as "Bicycling Science" by David Gordon Wilson, are provided as potential sources of information on the topic.

Areas of Agreement / Disagreement

Participants express differing views on whether to study bicycle stability with or without a rider, indicating that multiple competing perspectives remain on the best approach for the extended essay.

Contextual Notes

Participants note that the problem of bicycle stability is complex and has been debated for years, highlighting the unresolved nature of certain aspects of bicycle dynamics.

Who May Find This Useful

Students and researchers interested in bicycle dynamics, stability analysis, and those preparing extended essays in physics may find this discussion relevant.

manu101
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Hello! I'm new to the Physics forums so I'm not too sure if this is the right place. But hopefully it is :)
Anyway, I'm currently an IB student studying Physics at higher level and decided that I was going to do my EE (extended essay), which is about 4000 words, on physics.

Since I really wanted to do something related to stability, with help from my supervisor I decided to look into the stability of a bicycles. Anyway, I need help with deciding a few things to ensure I have enough content to write about for 4000 words as well as to be able to score high on my EE.

I'm investigating on two independent variables, two factors that affect how stable a bicycle is by measuring probably how much time it can stand upright without falling to one side. Nevertheless, I was wondering whether studying the stability of a bike with a rider on it or "rider-less" is better. The thing is that I think that studying the stability of a bike with a rider on it would be better as there are more factors that can be varied compared to rider-less, however, I feel like there is human error as we cannot ensure that certain variables will remain constant throughout all the trials (I hope you are getting my point).

Also, I need help deciding on what factors I should vary (I need 2 factors) so as to make my EE interesting and not such a straight forward answer. Here are some of the factors that I'm thinking of:

With rider: pressure of air in the wheels, weight distribution, height of the seat and/or handle, distance between handle and seat, distance between hands on handle, weight of rider (probably won't use this), distance between feet, fork angle.

Rider-less: pressure of air in the wheels, height of seat and/or handle, distance between handle and seat, angle of the seat?, fork angle

^^please feel free to add to the list, I'm trying to make it so the factors are not so "direct" but must still be measurable

Thanks for taking the time to read my threat, I'm open to any suggestions! :)
 
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Welcome to the PF. :smile:
manu101 said:
how stable a bicycle is by measuring probably how much time it can stand upright without falling to one side.
I'm pretty sure you mean "when rolling", not "when standing". Bikes fall over if they are not moving. :smile:

I'd vote for doing the analysis with a typical rider on the bike, since that is how they are used, and is the most important time for them to be stable. There have been some previous PF threads on the stability of bikes and motorcycles -- I will do a quick search to see if I can find a few to link to for you...
 
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Here's a Sciam article on it too:

https://www.scientificamerican.com/article/the-bicycle-problem-that-nearly-broke-mathematics/

Be aware that this is not a trivial problem and that folks have been arguing over it for years. Its akin to how the Stradivarius violin got its hauntingly beautiful sound.

Sometimes I wonder how classical physics was able to evolve and yet not have a good understanding of this phenomena. Einstein used to ride around on a bike a lot and apparently never considered it.

albert-einstein-riding-a-bike-768x509.jpg
 

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Get a copy of Bicycling Science Third Edition by David Gordon Wilson, and read Chapter 8: Steering and Balancing. Forty seven pages of everything you are looking for, and much more.
 
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jrmichler said:
Get a copy of Bicycling Science Third Edition by David Gordon Wilson, and read Chapter 8: Steering and Balancing. Forty seven pages of everything you are looking for, and much more.
I heard about this book while researching, thanks :)
 

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