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Orb

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The layer of liquid between two plastic domes contains small, shiny, flat crystals of mica, which show up the flow lines when the liquid moves. If you spin the dome, you see flow patterns reminiscent of the movement seen in the atmosphere of the planet Jupiter.

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Forces Space
When you spin the middle this is dragging a layer of the fluid which is in contact with the plastic. This layer is then dragging the layer beneath it and so on right the way through. The fluid around the equator (the middle of the sphere or the bottom of the dome) has the furthest distance to travel and therefore is moving the fastest. As the fluid speeds up it begins to twirl and ripple and the flow becomes turbulent, this begins at the equator and spreads outwards towards the pole (the top).

Planet Orb

The way that the fluid in the orb behaves is similar to that of a planet’s atmosphere. A planet’s atmosphere is pulled around by a combination of the planet’s rotation and also where it’s being heated from above by the Sun and sometimes also from below by the planet. Around the equator of Earth the atmosphere is travelling around a larger circle therefore is moving more quickly, this is one of the reason that storms form around the tropics. Jupiter is a very good example of turbulent winds, the largest storm on Jupiter is The Great Red Spot which is just south of its equator, this storm is large enough to swallow planet Earth three times over and has been observed by humans for more than three hundred years.

Steady and Turbulent flow

Turbulent flow is when the fluid is when a fluid is crashing around as it moves, it is disorderly and unpredictable, this is quite a normal movement for fluids. Turbulent flow occurs if the fluid is moving too rapidly and if any motion is out of line with the rest, when this happens it disrupts more of the surrounding fluid and becomes bigger and bigger, which is the way the turbulent flow within the orb spreads. Steady flow occurs more often in stickier (or viscous) fluids such as oil or syrup, though less viscous fluids like water can flow steadily is the speed is kept down.

Try this

Try this.

Try running a stick through some water and look at the water behind it. You may have caused small whirlpools to form, these are called vortices (or a vortex if there is only one), the vortices to the left of the stick will be spinning clockwise and the ones on the right will be spinning anticlockwise. You may feel the stick being pulled back and forth from left to right, this happens due to the turbulence and is a similar reason why a flag will flap in the wind.

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Look Closer

Welcome to Look Closer, Techniquest's brand new digital tool. We're trialling Look Closer as a way of offering you a closer look at the science demonstrated by many of our exhibits. You'll find visitor sheets, videos, articles on contemporary science as well as fun trails to navigate your way around the exhibition space.

Speak to our Science Communicators to find out more.