Which method can be used to prove a bent tube is clear of obstruction?

Using a wooden ball to prove that a bent tube is clear of obstruction exploits the principle of physical blockage. When the wooden ball is introduced into the tube, it should be able to travel through without encountering any resistance if the path is clear. This method is effective because it provides a tangible way to assess the internal conditions of the tube and ensures that there are no physical blockages that could hinder fluid flow.

The choice of a wooden ball is particularly advantageous because it is lightweight and can easily navigate a straight path in a clear tube. If the ball meets any resistance due to an obstruction, it will stop, indicating a blockage. This method is straightforward and can be easily executed in various scenarios without needing additional equipment.

Other methods, while they may help to assess or address blockages, can have limitations. Using a portable light, for instance, might not provide a comprehensive view of the tube's interior, particularly in bends or areas where light penetration is poor. Suction through a vacuum might help in removing debris but does not confirm that the entire path is free of obstruction. Water flushing is effective for clearing certain types of obstructions but could miss issues that are lodged within the bends or angles of the tube where water flow may not effectively reach.

Thus,