The Pythagoras cup, also known as a "trick cup" or "goblet of justice," is a clever device that demonstrates the principles of fluid dynamics and gravity.
Understanding the Design
The cup is designed with a central column that extends from the base to the top of the cup. This column has a hole at the bottom, connecting the inside of the cup to the outside. The cup's rim is designed to have a specific shape, usually a curve or a lip, which plays a crucial role in its functionality.
How It Works
- Filling the Cup: When you pour liquid into the cup, it fills up normally, as the hole at the bottom is blocked by the central column.
- Reaching the Critical Point: As the liquid level rises and reaches the top of the central column, the liquid starts flowing through the hole, creating a siphon effect.
- The Siphon Effect: The siphon effect causes the liquid to drain rapidly from the cup, leaving the user with nothing but the bottom of the cup.
The Secret
The secret lies in the shape of the cup's rim. The curve or lip on the rim ensures that the liquid level rises above the hole in the column, creating a siphon effect. Without this specific design, the liquid would simply overflow from the top without draining through the hole.
Practical Applications
While the Pythagoras cup is primarily a fun and educational tool, its principles can be applied in various practical scenarios:
- Irrigation systems: Similar siphon effects are used in irrigation systems to move water from a higher reservoir to a lower field.
- Drainage systems: Siphons are used in drainage systems to remove excess water from areas where gravity alone is insufficient.
In Conclusion
The Pythagoras cup is a simple yet clever device that demonstrates the principles of fluid dynamics and gravity. Its design cleverly utilizes the siphon effect to create a surprising and entertaining result.
