Brought to you by Carl Lu.

Is waterwalking possible?

Ever dreamed about walking on water? It won’t be impossible as long as we can get some ‘water’ that behaves like a solid to support your weight.

In reality, there is indeed a liquid that could behave like a solid when you apply a shear stress on it.

This type of special liquid is called non-Newtonian fluid.

Unlike conventional Newtonian fluids like water, the viscosity of non-Newtonian fluids is dependent on the applied shear stress. They will be either less or more viscous, notably shear-thinning or shear-thickening based on their nature.

So benefitting from the shear-thickening phenomenon, water walking might be possible!


Why does viscosity matter?

A good control of viscosity of matters has wide potential applications in real life, we just simply don’t know it’s related to viscosity!


  • Shear thinning:

Why do people always say: If you struggle harder in a swamp, you will fall even faster. That’s because a swamp is actually a non-Newtonian fluid. And the more shear force you apply to it, the more flowable it becomes.

In our daily life, ketchup is a non-Newtonian fluid as well! The use of a nozzle will give us better control over how much ketchup we want. Otherwise, if you don’t use a nozzle (not applying a shear force), you pour the ketchup instead, then enjoy a whole chunk of ketchup on your chips!

Observe how they behave in a slow-motion mode:

  • Shear thickening

A liquid body arm: By embedding a special type of shear-thickening fluids (STF), which is formed of hard silicone nanoparticles suspended in non-toxic polyvinyl alcohol in Kevlar fibres, the vest becomes extremely hard when impacted by a bullet. That’s because the viscosity of these fluids will become very high with the shear force applied.

Slow motion:

That is how amazing viscosity is! It can affect every area of our life!

So essentially, one material could perform in two completely different ways. And there are even more fun materials and knowledge in Materials Science and Engineering.

Now you can carry out some simple lab works – the Soliquid activity to explore the difference between Newtonian and non-Newtonian fluids in your own house and experience what lab works are like.

If you want, you can find a huge huge container with an appropriate ratio of water and cornstarch, you may achieve a waterwalk in your home!!!


To carry out this fun experiment yourselves, please find the instructions using the link: Soliquid-Instruction sheet and fill out the Soliquid-Results Sheet.

The Soliquid activity was developed by Carl Lu



  • Newtonian fluid – A Newtonian fluid is one whose viscosity is not affected by shear rate: all else being equal, flow speeds or shear rates do not change the viscosity.
  • Non-Newtonian fluid – A non-Newtonian fluid is a fluid that does not follow Newton’s law of viscosity, that is, it has variable viscosity dependent on stress. In non-Newtonian fluids, such as shear-thinning fluids and shear-thickening fluids, viscosity can change when under force to be either more liquid-like or more solid-like.
  • Shear-thinning fluids – The viscosity of the fluid Decreases as the shear rate increases
  • Shear-thickening fluids – The viscosity of the fluid increases as the shear rate increases


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