We still don’t really know how bicycles work

Forget mysterious dark matter and the inexplicable accelerating expansion of the universe; the bicycle represents a far more embarrassing hole in the accomplishments of physics.

Let’s be honest, a bit of the pleasure at Chris Froome’s victory in the Tour de France is down to this being our second victory in a row and to the thought that the French haven’t won it since 1985. What must be worse for them, though, is that when it comes to the science of team cycling, even the Belgians are in front.
 
At the University of Mons, researchers are developing something called the Anaconda. It’s never going to be much of a speed machine because it is, in effect, a chain of monocycles with handlebars. These units are connected, by means of hinges that allow them to snake along, to a normal two-wheeled bike at the front. Every rider in the chain can be going in a slightly different direction, which means it takes an enormous amount of control and collaboration to move the thing forward. According to Olivier Verlinden, chief engineer on the project, the main qualification for riders is to be unafraid of falling off.
 
It’s fun, apparently. The idea is to unleash it as a beach-resort bike, the kind of thing that stag and hen parties will use to terrorise seaside towns across the world. But it is also scientifically interesting. Why? Because we still don’t really know how bicycles work.
 
It is rare that most people appreciate the bicycle, but it is quite an extraordinary machine. Push a riderless bike, letting it roll freely at high enough speeds, and it can withstand pushes from the side – it will wobble a little, but quickly recover. In the conventional analysis, that is because the gyroscopic force of the front wheel, its mass and the spontaneous turn of the handlebars all act together to keep the bicycle rolling forwards. This has something to do with the gyroscopic effect, the force that keeps a spinning top upright. You can feel this by removing a wheel from your pushbike and spinning it while you hold the axle spindles. If you try to change the orientation of the wheel, you’ll feel it push back against you.
 
The first mathematical analysis of bicycles suggested that this is also what keeps a moving bike on its wheels. But although the equations were written down in 1910, physicists always had nagging doubts about whether this was the whole story.
 
The most definitive analysis came exactly a century later. It involved an experimental bicycle that had all its gyroscopic effects cancelled out by a system of counter-rotating wheels. The effort of building such a strange contraption was worth it: the resulting paper was published the prestigious journal Science.
 
The publication plunged bicycle dynamics back into chaos. It turns out that taking into account the angles of the headset and the forks, the distribution of weight and the handlebar turn, the gyroscopic effects are not enough to keep a bike upright after all. What does? We simply don’t know. Forget mysterious dark matter and the inexplicable accelerating expansion of the universe; the bicycle represents a far more embarrassing hole in the accomplishments of physics.
 
And it may not be solved any time soon; very few researchers are working full-time on bicycle dynamics and there’s very little money in it. Once we’ve discovered exactly how these contraptions work, it might be possible to come up with bold new designs of bicycle – perhaps even better than the Anaconda. But nobody is desperate for that to happen; not even the French.
 
Maybe that’s OK. In an age where we have worked out the history of the cosmos and the secret of life, it’s rather nice that the humble bicycle keeps our feet on the ground. 
 
Cyclists during the Tour de France. Photo: Getty

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 29 July 2013 issue of the New Statesman, Summer Double Issue

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A small dose of facts could transform Britain's immigration debate

While "myth-busting" doesn't always work, there is an appetite for a better informed conversation than the one we're having now. 

For some time opinion polls have shown that the public sees immigration as one of the most important issues facing Britain. At the same time, public understanding of the economic and social impacts of immigration is poor and strongly influenced by the media: people consistently over-estimate the proportion of the population born outside the UK and know little about policy measures such as the cap on skilled non-EU migration. The public gets it wrong on other issues too - on teenage pregnancy, the Muslim population of the UK and benefit fraud to name just three. However, in the case of immigration, the strength of public opinion has led governments and political parties to reformulate policies and rules. Theresa May said she was cracking down on “health tourists” not because of any evidence they exist but because of public “feeling”. Immigration was of course a key factor in David Cameron’s decision to call a referendum on the UK’s membership with the EU and has been central to his current renegotiations.  

Do immigration facts always make us more stubborn and confused?

The question of how to both improve public understanding and raise the low quality of the immigration debate has been exercising the minds of those with a policy and research interest in the issue. Could the use of facts address misconceptions, improve the abysmally low quality of the debate and bring evidence to policy making? The respected think tank British Future rightly warns of the dangers associated with excessive reliance on statistical and economic evidence. Their own research finds that it leaves people hardened and confused. Where does that leave those of us who believe in informed debate and evidence based policy? Can a more limited use of facts help improve understandings and raise the quality of the debate?

My colleagues Jonathan Portes and Nathan Hudson-Sharp and I set out to look at whether attitudes towards immigration can be influenced by evidence, presented in a simple and straightforward way. We scripted a short video animation in a cartoon format conveying some statistics and simple messages taken from research findings on the economic and social impacts of immigration.

Targeted at a wide audience, we framed the video within a ‘cost-benefit’ narrative, showing the economic benefits through migrants’ skills and taxes and the (limited) impact on services. A pilot was shown to focus groups attended separately by the general public, school pupils studying ‘A’ level economics and employers.

Some statistics are useful

To some extent our findings confirm that the public is not very interested in big statistics, such as the number of migrants in the UK. But our respondents did find some statistics useful. These included rates of benefit claims among migrants, effects on wages, effects on jobs and the economic contribution of migrants through taxes. They also wanted more information from which to answer their own questions about immigration. These related to a number of current narratives around selective migration versus free movement, ‘welfare tourism’ and the idea that our services are under strain.

Our research suggests that statistics can play a useful role in the immigration debate when linked closely to specific issues that are of direct concern to the public. There is a role for careful and accurate explanation of the evidence, and indeed there is considerable demand for this among people who are interested in immigration but do not have strong preconceptions. At the same time, there was a clear message from the focus groups that statistics should be kept simple. Participants also wanted to be sure that the statistics they were given were from credible and unbiased sources.

The public is ready for a more sophisticated public debate on immigration

The appetite for facts and interest in having an informed debate was clear, but can views be changed through fact-based evidence? We found that when situated within a facts-based discussion, our participants questioned some common misconceptions about the impact of immigration on jobs, pay and services. Participants saw the ‘costs and benefits’ narrative of the video as meaningful, responding particularly to the message that immigrants contribute to their costs through paying taxes. They also talked of a range of other economic, social and cultural contributions. But they also felt that those impacts were not the full story. They were also concerned about the perceived impact of immigration on communities, where issues become more complex, subjective and intangible for statistics to be used in a meaningful way.

Opinion poll findings are often taken as proof that the public cannot have a sensible discussion on immigration and the debate is frequently described as ‘toxic’. But our research suggests that behind headline figures showing concern for its scale there may be both a more nuanced set of views and a real appetite for informed discussion. A small dose of statistics might just help to detoxify the debate. With immigration a deciding factor in how people cast their vote in the forthcoming referendum there can be no better time to try.