This video was taken at Heureka Science and Technology museum, Vantaa, Finland. Heureka, is the place to experience science with all our senses live through practical demonstration. The above video is called "Straight Through the Curve", Meaning, how can a Straight rod pass through the curve without disturbing the curve and any other object nearby. Can a straight steel rod pass through a curvical slot? but it does as seen in the above video. Lets debug the physics behind it. 

1, The straight stick/rod is attached to the verticle rod(axle).

2. The curvical plane or slot is also attached to the vertical rod.

3. Ends of the Straight Rod is having metallic sphere shaped

4. The straight rod is positioned in certain angle in such a way that the ends of the stick are farther from the vertical rod

5. Each of the end points also can pass through the opening provided in the curvical plane.

6. Notice that the shape of the opening (Curvical slot) is a Hyperbola.

7. The surface which the straight stick describes as it spins around its axle is a Hyperboloid.

It is often difficult to perceive the path that a moving object will take in reality. As a real time eample we can say shifting our residence from 1 location to another, sometimes we may think how we took the sofa inside our residence when we feel difficult while moving it out. 

comment your views and your scientific explanation to this experiment if anyso that it would be a learning for me and visitors. Thanks for reading