Questacon Kugel Ball - Canberra, ACT, Australia
S 35° 17.888 E 149° 07.888
55H E 693807 N 6091811
This heavy granite ball sits in a specially made cradle, so it can be easily spun.
Waymark Code: WMZ568
Location: Australian Capital Territory, Australia
Date Posted: 09/10/2018
Views: 5
The Kugel Ball is in the entry court to the Questacon Science Museum, and there is an Interpretative Sign explaining how can work. A metal plaque on the base of the stand gives this information:
Floating Granite Sphere
Weight: 633 kg
Diameter: 750 mm
Water Pressure: 48 kPa
Material: Australian Granite
Made in Australia
Installed at Questacon in September 1998
While in the glass window of the front of the Science Museum is a sheet with this information:
Granite Ball
633 Kilograms
750 millimetres across
You can make it spin
[Sectional Diagram of the ball, and entry of the pressurised water.]
"Gravity is pulling the ball downwards. Mains pressure water is pushed up under the ball and spreads out. The push of the water is just enough to lift the ball about one tenth of a millimetre against the pull of gravity.
"The water also acts as a lubricant when the ball spins. The ball and the bowl are both very smooth and shaped to fit exactly. This reduces friction and makes it easy to spin the ball.
"All surfaces are bumpy. Even very smooth surfaces have bumps that can be seen with a microscope. When you try to move one surface over another, the bumps get in the way and make the movement difficult. This is called friction.
"In engineering workshops, liquid or air is often forced underneath heavy objects so that they can be moved easily."
Address: Questacon, King Edward Terrace, Canberra, ACT, 2600, Australia
Visited: 1608, Sunday, 2 September, 2018