Roll out of the straight line

Roll out the straight line - Science Museum exhibitions exhibition items scheme

What It Shows

This exhibition mainly introduces the scientific knowledge and principles related to circles and hypocycloids, allowing visitors to have a deeper understanding of the characteristics of circles through interactive experiences.

Science Behind It

Circumference is a mathematical term that refers to a trajectory on a plane, in which a moving point moves one circle around a certain point and a certain length as the distance. It is called a circle, or simply a circle. A moving circle is inscribed on a fixed circle for non sliding rolling. The trajectory of a fixed point on the circumference of a moving circle is called an epitrochoid. The production factory of Science Museum exhibitions, Shanghai Inertia Automation Co., Ltd., reminds everyone that when a small circle cuts into a large circle and rolls along the large circle, if the diameter of the small circle is exactly half of that of the large circle, then any point on the edge of the small circle, that is, the trajectory of the epitrochoid, will be a straight line and pass through the center of the large circle.

How to Take Part

Exhibition items showcase the unique state of the epitrochoid in special situations to visitors through mechanical interaction.

Description

Set up a large disk with a small toothed disc engraved on it, and the radius of the small circle is half of the radius of the inscribed large circle. Mark a point at the edge of the small circle. Shanghai Inertial Automation Co., Ltd. is the original factory for the production of science museum exhibitions, and it reminds everyone to turn the handwheel. If a small circle rolls along the edge of a large circle, it will be found that the motion trajectory of the marked points on the small circle is always a straight line passing through the center of the large circle.

video demonstration