Astronomical clock, Prague

Dating back to 1410, the Astronomical Clock in Prague is one of the oldest astronomical clocks in the world and the oldest one still operating. Every hour, there is a clockwork display called "The Walk of the Apostles", where statues of Apostles and other figures including Death appear followed by the clock chiming the hour.

One of the interesting features of the clock is the 24-hour face with present day time and Old Czech Time on the outer ring. This ring moves each day with 24 indicating the sunset.

Zodiac symbols appear on the astronomical dial (top) and calendar (below).  

In the above photo, taken at 13:49 on 27 March 2019, the clock shows the Sun has recently exited from Pisces into Aries, the Moon is near the Last Quarter phase, and the hour hand is approaching two in the afternoon.   

More info on all the features of the clock is available on Wikipedia.

Pre-vinyl Recorded Music

On a recent trip to Prague, we visited the Nostalgic Museum. The owner had a large collection of devices for playing recorded music before vinyl records were popular. These included music boxes and organs that played using metal or cardboard discs or paper rolls.

Gramophone

A few music players in action

A multi-instrument music player

A multi-instrument music player. Cymbals, drum, chimes, and triangle.

Phonograph. Uses a wax cylinder.

Zinc discs

Ariston. Uses rotating cardboard discs and compressed air. 

Herophon. The plate is stationary while the machine rotates.

Mechanical Autoharp

Baroque Clock

Robotic exoskeleton prototype

Pocket Bikes

Reinventing the Wheel : TreeHugger
Mountain biker and designer Duncan Fitzsimons has invented a folding wheel with the aim of making courier or city bikes that could be folded up into a package that is much easier for carrying on public transport.



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Theo Jansen: The art of creating creatures

Wind powered kinetic sculptures.

Chain reaction

Gravity based contraptions

Remember that marble run game we had as kids?

Here's a video of a Japanese marble run