Walking on Liquid: Surprising Fluids and the Physics Behind It

Have you ever wondered if it's possible to walk on liquid? It sounds like something out of a science fiction novel or a dream, but in reality, it is indeed possible under certain conditions. This article explores the fascinating physics behind these phenomena, focusing on non-Newtonian fluids, surface tension, and the materials that can mimic walking on water.

The Myth of Walking on Water

First, let's address a common myth: walking on water. Many people might think it’s impossible, but it can be quite close if we consider unconventional methods. However, the traditional concept of walking on water, like seen in religious stories, is purely impossible under normal conditions. According to the Mythbusters, no matter how big you make your footwear, it is not possible to walk on water as it behaves like an incompressible fluid.

Custard as a Non-Newtonian Fluid

One of the most interesting and delicious fluids that can support a person's weight is custard. Custard is a non-Newtonian fluid. Unlike most fluids, its viscosity changes based on the forces applied to it. When a person walks steadily on custard, it can provide a supportive surface for the duration of the step, thanks to its resistance to flow. To walk on custard, one needs to maintain a steady pace without stopping. A sufficient depth of custard is also crucial. It is worth noting that custard not only supports the weight of a person but can also be enjoyed as a dessert, making it both a practical and delicious material.

Water as a Liquid Ground on a Rainy Day

While custard may seem like a whimsical option, the rain-soaked ground also offers an interesting scenario. On a rainy day, when the ground is wet, it behaves like a thin liquid layer. While this layer is generally not very thick, it can still be considered a surface. However, walking on such a thin layer of water is nearly frictionless, making it perilous. Even though it is possible, it would be challenging to maintain balance without slipping.

Mercury: An Extreme Example

For something much more challenging, consider mercury, a highly toxic heavy metal. At room temperature, mercury is a liquid metal. An average adult weighing 160 pounds would displace just under a gallon of mercury, standing with their feet around a foot and a half below the surface. If one could manage to stand upright in such a situation (impossible without specialized equipment), walking on mercury is theoretically possible. However, the risk of both toxicity and extreme caution required makes it infeasible under normal conditions.

Surface Tension and Soap

Surface tension plays a key role in these scenarios. Surface tension is the force that allows small drops of water to shape into spheres and makes it possible to walk on certain surfaces. However, even a small amount of soap can significantly reduce this surface tension, making it difficult to walk on the surface.

Slipper Boogie Boards

Interestingly, it is possible to create a makeshift 'boogie board slipper' that can theoretically allow a person to walk on water. If one buys two boogie boards and straps them to their feet, they can simulate walking on water. However, it is important to note that this is more of a practical joke rather than a real-world technique. The supporting structure in this case is the buoyancy provided by the boogie boards, not the interaction with the water itself.

In conclusion, while walking on water as traditionally imagined is not possible, walking on custard, rain-soaked ground, and even mercury under specific conditions is theoretically within reach. The key lies in the physical properties of the fluid or material and the ability to maintain balance. Understanding the physics behind these phenomena can lead to innovative and practical solutions in various fields.