Magnetic Tensegrity Table

Nice Physics Showpiece!

I recently discovered a new physics toy to add to my collection. The beautiful Magnetic Tensegrity Table is shown below. It's made in Britain and comes unassembled in a small box.

The height is about 5 inches, just under 13 centimeters. Many parts and screws were extremely small. They challenged my diminished dexterity during assembly. But the assembly instructions were excellent! In fact, I've never seen a better illustrated, clearly worded, step by step assembly guide!

So how does it work? Three vertical wires evenly spaced around the edges of the circular base and top are under tension. The wires can't support a load by compression, so they are not supporting the top. The small powerful magnets suspended by hooks are attracting each other and would seem to draw the red top and base together. So how does the top stay up?

The curved silver magnet supports are the key. Look at the upper magnet. It is pulled down by the attraction of the magnet below. The downward force on the upper magnet presses its (left) silver support down onto the red base. Now look at the bottom magnet. It is pulled up by the attraction of the magnet above. The upward force on the bottom magnet presses its (right) silver support up against the red top. So the base is pushed down while the top is pushed up! That's why the wires are under tension!

There's enough lift on the top to support extra weight. The next picture shows a 200 gram mass resting on the table top! 

The manufacturer suggested the table would hold up to about 260 grams before collapsing. I foolishly tried 300 grams, and, yes, the whole thing collapsed! It wasn't easy to separate the magnets and reassemble the table, but, after an hour or so, I eventually succeeded. I'll stick to the 200 gram mass from now on.