perturbation

per.tur.ba.tion

-noun

1. the act of perturbing

2. the state of being perturbed.

3. mental disquiet, disturbance, or agitation.

4. astronomy. deviation of a celestial body from a regular orbit about its primary, cause by the presence of one or more other bodies that act upon the celestial body.

World English Dictionary

5. physics. a secondary influence on a system that modifies simple behavior, such as the effect of the other electrons on one electron in an atom.

6. astronomy. a small continuous deviation in the inclination and eccentricity of the orbit of a planet or comet, due to the attraction of neighboring planets.

Science Dictionary

7. a small change in a physical system, most often in a physical system at equilibrium that is disturbed from the outside.

8. variation in a designated orbit, as of a planet, that results from the influence one or more external bodies. Gravitational attraction between planets can cause perturbations and cause a planet to deviate from its expected orbit. Perturbations in the orbit of stars have led to the discovery of planetary systems outside our solar system.

http://dictionary.reference.com/

555 timer chip and sound generator

Here are three examples of circuits that have variable outputs. As the air pressure increases it forces the water in the tube up, completing an open circuit between two wires, acting like a switch, to then make a sound, beep, hum, signaling a change in pressure.

(source: http://home.cogeco.ca/~rpaisley4/LM555.html#4)

Collecting Materials & Supplies

Looking for materials (air/gases/liquids) that deflect easily to changes in air pressure.

Also looking at various liquids as to their various properties of:

Density

Viscosity

Conductivity

-because water is 13.6 x lighter than mercury it will climb that much faster and further than mercury as a barometer. As a result, it will reflect a more architectural scale.

-tubes ranging through several floors, was well as at several different levels and altitudes.

-the material needs to have a greater density than water, but is less viscous, and if is to become a switch, or pot then it needs to be conductive.

-need to determine if as the pressure along the tube changes does the relative capacitance along the tube change?

-water conductivity - electrolyte solution - can conduct electricity

(ion = wanderer in Greek)

-table salt NaCl electrolyte

Liquids Denser that Water Temp t (C) Density p (kg/m3)

water 4 1000

sulphuric acid (95% onc.) 20 1839

mercury 25 13590

iodine 25 4927

chloride 25 1560

bromine 25 3120

Conductivity

-iodine would make a great choice as a pressure sensitive material except that it is not conductive.

-the conductivity of water increase as the NaCl ratio increases.

(source www.horiba.com)

Salinity (density of salt in salt water) and conductivity. Liquid temperature 25 degrees C

NaCl density (w/v)% Conductivity (mS/cm)

0.1 2.0

0.5 9.2

1.0 17.6

1.5 25.6

2.0 33.0

The more Na+ and Cl- contained in water the more electricity is carried, and the higher the conductivity. Therefore if we know the conductivity of a sample of salt water, we can calculate just how salty the water is.

Group Crit

-strain gauge sensor can measure subtle changes

-will need some sort of sealed unit

-high scaled physics supplies or lab equipment, i.e. long silicon tubing suspended

-need some sort of visual registry - at building scale - need a tall scale - hight of the room 20'-30' therefore operating at an architectural scale and will then populate the space with changes in the pressure throughout the room and how populated in space

-it needs a certain amount of behavior

-level of indication

-something that responds to changes in small behaviors of expansion and contraction to make it perceivable

-becomes a question of scale and leverage (Go big or go home!)

-Nick - water switch makes the connection to complete the circuit

-everything affected by pressure.

ISEA 2010 RUHR Exhibition

International Symposium of Electronic Art

Verena Friedrich (de)

"Transducers"

Transducers is an installation composed of several glass tubes, each containing a single human hair. Mimicking scientific examination methods the object under investigation – the human hair – is triggered by the machinery and is stimulated to react. This reaction is registered, amplified and transduced into a sound. Each of the devices generates a unique sound based on the individual specimen from each donor.

http://www.isea2010ruhr.org/programme/exhibitions/isea2010-ruhr-exhibition/friedrich

(mechanical transduction techniques)