Bicycle Physics

Spring is a great time to teach a child how to ride a bike. Since learning how to ride a bike is such an important rite of passage for kids, we thought is was worth sharing that the long held view of how a bike maintains it’s balance was recently re-imagined. We came across this in a list of Discover Magazine’s 100 Top Stories Of 2011 reported by Gillian Conahan.

As your little Lance Armstrong soon finds out (while scaring the daylights out of mom and dad :) it’s possible to ride a bike with no hands. A moving bicycle can recover from wobbles with no steering input and even without a rider. The story behind the physics is a little more complicated than, “Look mom, no hands”. In fact, it’s never been agreed upon exactly how a moving bicycle maintains its balance. Many argue the rotating wheels act like a gyroscope and keep the bike stable (that one makes the most sense to me) while others maintain the “trail” (the angle between the steering axis of a bike and the point of contact with the ground) ensures stability during turns.

This past year Dutch and American engineers built a better bicycle (or at least one that defied both theories) by devising a bike with a minimal trail and with discs that rotate in the opposite direction of its wheels to cancel out the gyroscopic effect. The big finding? Even without either form of stabilization, the bike was able to stay upright, maintain balance and cruise along riderless.

“It shows that what everyone thought about bicycle self stability for the past 110 years is wrong,” says Cornell engineer Andy Ruina. “Neither gyroscopes nor trail are necessary.” Other factors like distribution of mass in the front frame by  mounting the front wheel forward of the usual place played an important role in keeping the bike upright. What does this all mean? As Sid The Science Kid says in our sons favorite new TV show, maybe we will end up with some Super-Duper-Ooper-Schmooper new bike designs in the near future.

You will still need plenty of good old fashioned energy to pedal the bike, no matter how it balances. Pasta is a great source of energy and Mac & Cheese is one of the best ways to serve it up :) See you next week. xo –Amelia