The Pyro Board: A Two Dimensional Ruben’s Tube

German physicist Heinrich Rubens became a god among nerds in 1905 when he invented a tube that uses fire to visualize standing sound waves. When there is no sound fed into the tube, the flames rise to the same height. When a sound is added into the tube, the waveform actually affects the amount of gas that is fed through each hole.

At the point of maximum displacement on the wave (the anti-node), the gas pressure varies. The pressure is highest when the wave crests and the gas is pushed closer to the hole, which forces more fuel out and causes the flame to grow higher. When the wave pushes down into the trough, it can’t really suck the gas back in. The flame has enough gas and oxygen to remain burning higher until the wave crests at that point again.

The part of the wave which crosses the midline and remains unchanged is referred to as the node. This area in the Rubens tube doesn’t have the pressure fluctuation and remains relatively low.

Of course, volume plays a big role on how these flames appear. The above description applies when the volume is high, but if the incoming sound is quiet, the crest of the wave isn’t enough to overpower the opposite pressure of the trough, and the anti-nodes actually appear smaller than the nodes.

Derek Muller from Veritasium traveled to Denmark in order to check out an updated version of the Rubens tube. These physicists and chemists have developed an apparatus with 2,500 holes in the top. The key difference is that these holes are not all in a line like a traditional Rubens tube, but actually cover an entire plane.

The results are pretty amazing. Check it out:

inFORM is a Dynamic Shape Display that can render 3D

inFORM is a Dynamic Shape Display that can render 3D content physically, so users can interact with digital information in a tangible way. inFORM can also interact with the physical world around it, for example moving objects on the table’s surface. Remote participants in a video conference can be displayed physically, allowing for a strong sense of presence and the ability to interact physically at a distance. inFORM is a step toward our vision of Radical Atoms: http://tangible.media.mit.edu/vision/

Credits:
Daniel Leithinger*, Sean Follmer*, Hiroshi Ishii
* Contributed Equally
Academic Support:
Alex Olwal

Software Engineering Support:
Akimitsu Hogge, Tony Tang, Philip Schoessler

Hardware Engineering Support:
Ryan Wistort, Guangtao Zhang, Cheetiri Smith, Alyx Daly, Pat Capulong, Jason Moran

Video and Photo Support:
Basheer Tome, Jifei Ou

We are currently exploring a number of application domains for the inFORM shape display. One area we are working on is Geospatial data, such as maps, GIS, terrain models and architectural models. Urban planners and Architects can view 3D designs physically and better understand, share and discuss their designs. We are collaborating with the urban planners in the Changing Places group at MIT on this (http://cp.media.mit.edu/). In addition, inFORM would allow 3D Modelers and Designers to prototype their 3D designs physically without 3D printing (at a low resolution). Finally, cross sections through Volumetric Data such as medical imaging CT scans can be viewed in 3D physically and interacted with. We would like to explore medical or surgical simulations. We are also very intrigued by the possibilities of remotely manipulating objects on the table.

Past research on shape displays has primarily focused on rendering content and user interface elements through shape output, with less emphasis on dynamically changing UIs. We propose utilizing shape displays in three different ways to mediate interaction: to facilitate by providing dynamic physical affordances through shape change, to restrict by guiding users with dynamic physical constraints, and to manipulate by actuating physical objects. We explore potential interaction techniques and introduce Dynamic Physical Affordances and Constraints with our inFORM system, built on top of a state-of-the-art shape display, which provides for variable stiffness rendering and real-time user input through direct touch and tangible interaction. A set of example applications demonstrates how dynamic affordances, constraints and object actuation can create novel interaction possibilities.