APS centennial meeting bubble design.

This document was used for setting up a giant bubble display at the Georgia World Congress Center. In case you are trying to build your own, you may find this information useful.


March 9, 1999 revision
Final revision.

Please refer to the drawings below for more detail. The yellow area I will call the bubble exhibit area.


The ceiling of the hall is about 40 feet, with roof beams extending 10 feet below that. The goal is to hang the soap solution as high as possible, taking adavantage of as much of the full 40 feet as possible. One roof beam will be near, since it rests on the roof support pillar, but, should not interfere with the operation of the exhibit.

There apprear to be no air ducts or ventilation grates which will blow directly onto the film; Air conditions appear favorable.

How the display will be built.

The bubble works as follows (see the picture below). Two vertical nylon (30 pound test) wires are suspended from a nozzle. This nozzle will be part of a cage to be supplied by M. Rutgers. This cage will hold a 1 gallon fluid reservoir, a motorized valve and the necessary tubing.

This apparatus weighs about 10-20 lbs, and be made of aluminum, and a plastic bottle. It will be attached near the ceiling using a span set. The strings and weight hanging down from it will weigh only one pound. One low voltage DC cable will go to the floor for motor control, and one 1/2 tygon and teflon tube will go to the floor to supply fluid.
The following image is a photo of the cage which holds the bottle. This cage should be hung AS HIGH AS POSSIBLE. One does not need to be able to see this cage, and one does not need to be able to see the bubble up there. The higher the cage is hung, the wider the bubble can get, since the width depeds on the height.

A picture of my grad student is shown next to the cage for size.

During operation: Once solution has wetted the wires, they can be pulled apart, and the film will flow between them. Pulling the wires up to 12 feet apart will produce a gigantic film. A set of secondary lines (red in the picture below, green in the picture above) are pulled by the operator to separate the primary ones (black). The operator will sit behind a small table, to which a reel and guide device (shown above) will be clamped. The operator will also hold a small control box for regulating flow.

The pull lines need to pull against something. This can best be done by suspending steel (1/4" to 1/8" diam) cables (green, red dots in the plan view) between floor and ceiling.

These cables do not need to support much tension and should be anchored near the ground from cement blocks (or some type of weight) in excess of 40 pounds.

The following picture is a schematic setup of the bubble sheet.


SAFETY ISSUE: The film will break periodically, and some spray will result. Directly under the film, an area of perhaps 10 by 10 feet, should be covered with some sort of slip resistant doormat material, or rubber mats of some sort. The whole area (20 by 20 feet) should be carpeted, to prevent further slipping of visitors.

The entire two back walls of the film exhibit must be draped with black curtains (30 or 40 feet high on the side with the wall, the full 40 feet high if possible on the side facing thepresentation area. These curtains will protect the film from air flows in the exhibition space, and the black color will reduce back lighting, and emphasize the brilliant reflected colors.

The pump and valve will require power. A form requesting power has been sent to GWCC.

The operator will sit behind the film, and a small 2 foot by 2 foot table has been ordered with GES. One chair for the operator has also been ordered.

Lighting

The film will reflect light in the same way that a mirror does. Consider illuminating a mirrored wall in such a way that no matter where one stands, the entire wall uniformly reflects light. This can only happen when the full area behind and above the observer emits light uniformly. This is only possible with large white glass skylights, but maybe there is a solution.

Three 1000 watt lights have been ordered from GWCC.

The following two figures give an idea of a good lighting scheme, side view and top view.


I was working under the assumption that the light beam could be made to diverge at 30 degrees. One light should be hung 8 feet in front of the center of the display, aiming down at 60 dedgrees.

A second set of two lights should be further out, to facilitate viewing of those standing further away from the display. These lights are 30 feet out from the display, again, 30 degree beam divergence, but, aiming 30 degrees down.

Lighting control will probably be available in the form of a breaker on the roof support column.

Erecting the display

I (maarten rutgers) will arrive in atlanta at noon, the saturday before the meeting, and can assist in erecting the display. GES will install curtains, steel cables, fluid catch basin, and generally everything but the flowing film and it's immediate components. GWCC will supply lights and power and a water line to the display. Water and power should be in the back corner of the display, where the operator will sit.

Once all of the GES equipments is in place, I will come and finish the rest (WE NEED TO PICK A TIME FOR THIS). I will need a high rider vehicle for about 2 or 3 hours during this period, and an operator. Once the bubble is flowing, there is a small chance we need to make minor adjustments to the lighting (small chance means probably not).

Operation during the meeting

One person will be able to operate the display. It will run continuously for at least three hours from a 5 gallon carboy of soap solution (97% water, 3% Dawn dish soap). A wet vac will be useful in case of small spills. Access to a janitors closet, or other area with a large sink will be useful also.

List of materials ordered from GES (or GWCC if noted)

Materials needed for the setup.

  1. Black drapes, 27 feet high, 40 feet wide.
  2. Carpeting, 20 by 20 feet (color same as other nearby displays)
  3. Fluid catch, being designed by GES. About 10 by 10 feet.
  4. Two steel cables (1/8" to 1/4" diam) and top and bottom attachement points.
  5. 2 by 2 foot table and one chair.
  6. span set for hanging actual soap film
  7. 3 stage type lights (WATTAGE?) mounted to ceiling (GWCC)
  8. access to lighting control for the exhibit operator (GWCC)
  9. 1 120V single phase grounded outlet, available in the back corner of the display. (GWCC)

Other materials and services

  1. Two 5 gallon drinking water carboys.
  2. Access to a janitors closet or large sink.
  3. Wet vac or mop and bucket.
  4. High rider (2-3 hours) during final exhibit construction.