Gyroscope in a Suitcase

Demo:

Gyroscope in a Suitcase (outside)

Gyroscope in a Suitcase (inside)

 

This demonstration consists of a gyroscope in a brown suitcase. While the gyroscope is spinning, a person picking up the suitcase will start to notice some weird effects. If we assume the gyroscope is spinning forward when picked up, walking in a straight line will show no effects. As the person makes a left turn however, the briefcase will bend inward towards the carrier. As the person makes a right turn , the briefcase will bend outwards away from the carrier. These effects are all due to the changes in angular momentum of the gyroscope.

The angular momentum direction can be found by using the right hand rule on the spinning gyroscope. The equation for angular momentum is as follows where L is the angular momentum, I is the moment of inertia, and w is the angular velocity. 

\vec{L} = I\vec{w}

The torque of the gyroscope can be calculated with the following equation where T is torque, dL is a small change in angular momentum, and dt is a small change in time. 

\vec{T} = \frac{d\vec{L}}{dt}

Since for our suitcase, the only change in angular momentum comes from the change in direction, not the change in magnitude, when the suitcase is rotated a small angle, d\theta , in a small time, dt, then the torque equation is shown as follows.

\vec{T} = \frac{\vec{L}sin(d\theta)}{dt}

This shows why taking a turn will result in a torque on the suitcase, but not walking in a straight line.

The gyroscope is powered by 2 9V batteries attached to a switch and motor. The circuit diagram can be seen below.

Gyro in a Suitcase Circuit Diagram

Written by: Finn Amend