Posted in Fun Facts

The Twist of Time

So I came across a video which shows steve spangler doing an experiment called the twist of time. It involves the concept of laminar flow and viscosity

This video amazed me and probably many others as well. It achieved a certain “back in time” effect. Take a look at the video below.

What is happening here is that the colour that he has placed into the syrup did not mix, it actually does a whirl around the cylinder as he turns the inner cylinder. Note that corn syrup is used because of its high viscosity, therefore allow for laminar flow, as the Reynolds number is much less than 1. We shall not go into Reynolds number for this, but let’s look at how it happens.

How it happens is that the inner cylinder creates a pull on the corn syrup that is closer to it, and the corn syrup closer to the outer cylinder does not move that much. This creates a spiral if seen from the top.

Note that this has to be done slowly, and therefore creating laminar flow instead of turbulent flow. With laminar flow, they will be moving equally and therefore not mixing with each other and creating a spiral because the inner cylinder is pulling the liquid away from the outer circle. The spiral line gets thinner with every turn, and most videos online will do about 5-7 turns.

It is then reversible because as you turn it back, the thin spiral lines will also be turning back, and because it did not mix, we can see it forming up again slowly as we turn it back to the original position.

Great idea to show the concept of laminar flow. The equipment used for this would be a Couette’s Cell for demonstrating Laminar Flow.

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