A domino can knock over another domino about 50% larger than itself. A chain of dominos of increasing size makes a kind of mechanical chain reaction that starts with a tiny push and knocks down an impressively large domino.

Original idea by Lorne Whitehead, American Journal of Physics, Vol. 51, page 182 (1983).

Long version:
www.youtube.com/watch?v=y97rBdSYbkg

As seen on the British TV series "QI".

Tags:   physics domino topple fall dominoes chain reaction

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Rimming flow of a viscous fluid in a horizontal rotating tube. The fluid becomes unstable to the development of fingers that are sometimes called "shark teeth".

Here the oscillation is caused by motor problems.

Movie by Gary Yan and Marina Chugunova.

Tags:   Rimming Flow physics experiment fluid mechanics shark teeth instability pattern formation viscosity

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Everybody knows that you can see if an egg is boiled by giving it a spin. A raw egg stops quickly because the viscous goo inside damps out the motion. But what happens if you spin a boiled egg on one of its "long" sides? Then it turns out the spinning egg is unstable to standing up on one of its round ends. The end with the smallest curvature is most stable. The "long" sides have two different radii of curvature and the point of contact is unstable.

See
Moffatt, H.K. & Shimomura, Y. Spinning eggs - a paradox resolved. Nature, 416, 385 - 386, (2002).

www.nature.com/news/1998/020325/full/news020325-6.html

Tags:   egg physics spin instability top

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