The Earth and atmosphere are in constant motion due to a range of natural processes such as seismic activity, volcanic eruptions, and glacial slippage. Atmospheric phenomena such as hurricanes, thunderstorms, and tornadoes also contribute. At first, these events can be both majestic and alarming. Increasingly, these are rarely experienced directly, as more of the Earth's population live in towns and cities, insulated from these expressions of nature. The acoustic signals of natural terrestrial and atmospheric changes are evermore obscured by the background anthropogenic noise of airports, trains, and motorways. Technology further isolates the modern human from the natural environment in which we evolved. Seeking to reinvigorate and inspire our relationship with the natural environment through the use of inaudible frequencies, one of us, the artist Juliet Robson, aimed to create an interactive artwork that would re-establish this diminishing link. Robson wanted to create a piece that was tangible in a very real sense and that allowed a way into the important, but sometimes inaccessible, research done by scientists. This would align with the view that “Artists are no longer concerned with creating artwork that reflects or interprets reality; rather, they want to be active agents in creating it … That means that artists need to have an even deeper understanding of the mechanics behind science and technology” (Williams, 2017).

To undertake this, it was apparent that such a project would need to call on science, technology, engineering, and maths (STEM) expertise to create an as authentic as possible representation of natural hidden vibrations through an immersive experience. Robson approached two scientists and a mathematician to explore the possibilities of making the hidden frequencies of the stars and natural phenomena of our planet heard and felt. Art–science collaborations highlighting the unseen and intangible processes occurring around us that are demonstrated to the wider public have been undertaken before and continue to generate interest. Ezquerro et al. (2019) sonified sediment samples to make 14 distinct compositions based on the lithography and structure of each sample. Hooker (2011) designed an installation which detected high-energy particles from outside our solar system, which pass through humans without leaving a trace, and used it to trigger notes on an electric piano. Collaborating with scientists and researchers globally, Patterson (2007) created a phone line that could be called from anywhere in the world through which one could listen to a glacier melting. In addition to this, McMullen (2005) described how a group of artists worked with scientists at the European Organization for Nuclear Research (CERN) to create artworks which reflected theories in the realm of physics, such as the crumple effect.

One of the scientists Robson contacted was co-author Graeme Marlton, a meteorologist who was working on the Atmospheric Research Infrastructure in Europe 2 (ARISE 2) project (Blanc et al., 2018). The project encompassed the examination of a multitude of different novel measurement techniques to measure the dynamical properties of the atmosphere. One such technology utilised in ARISE2 was infrasound measurements. Infrasound contains sound frequencies which fall below the audible range of human hearing and are essentially sound waves below 20 Hz. It is produced naturally or artificially by large explosions, such as that of a nuclear detonation or by mining activity, and trains and planes. Natural infrasound is produced by volcanoes, earthquakes, glaciers, ocean swell, thunderstorms, hurricanes, and even the aurora borealis (Wilson, 1969), as shown in Fig. 1. The importance of infrasound in the ARISE project was learning about the state of the atmosphere by examining how infrasonic waves passed through it from a known infrasound source, such as a volcano (Smets et al., 2019).

It was suggested by Marlton that infrasound could be used as a medium for Robson's new project, and Robson was interested in the possibility of experiencing its inaudible symphony. Infrasound has featured in art installations before. Granchow (2015) produced an installation called the “Long-wave synthesis” which aimed to challenge how we perceive our environment and long-wave vibration. Grupfinger (2009) built an installation that allowed the audience to experiment with and experience a range of infrasound. Anish Kapoor (Aerotrope, 2012) produced an installation entitled “anxious” with an engineering company that played infrasound through the body at 18 Hz in a confined place to emulate the feeling the space was haunted. Barres (2017) discussed, in a review of Kapoor's works, how Kapoor was not successful as the installation caused anxiety in the visitors and museum staff.

To provide new access to natural infrasound, the raw infrasound data could be processed to provide a sound wave which could be played through commercially available transducers. Transducers are devices which shake when a low-frequency sound is played through them. They are fitted in 4D cinemas and video gaming chairs to provide a vibrating sensation to the spectator when an explosion or aircraft passes over on the screen to make the experience more immersive. The aim here was to enable people to feel their bodies resonating with the inaudible symphony of the planet. Figure 2 shows the initial concept work drawn up for the project. This would become one of the two working strands for Robson's immersive new project.

The other strand is not discussed at length here, but a brief description is given. It took astronomical measurements of the stars and, from their spectral signature, derived a sound wave. Sound waves move through a star's gaseous interior because of temperature changes, which cause the star to fluctuate in brightness. Satellites, such as the North American Space Agency (NASA)'s Kepler satellite and the Transiting Exoplanet Survey Satellite, can observe these vibrations. Data for hertz were obtained from NASA's Kepler project (Chaplin et al., 2011) and then sonified and played through Chladni plates built for the project. Chladni plates consist of a flat sheet of metal, usually circular or square, mounted on a central stalk on a sturdy base. When the plate oscillates during a mode of the vibration, the nodes and antinodes form complex but symmetrical patterns over its surface. The positions of these nodes and antinodes can be seen by sprinkling sand upon the plates. The sand will vibrate away from the antinodes and gather at the nodes (Stöckmann, 2007). As the frequencies of different stars were played through the plates, the sand sprinkled on the plate formed geometric patterns related to that star's frequency. Chladni plates have been used as a method of visualising sounds and music, as documented by Stanford (2013).

As the connection between the two strands was that of vibrations, oscillations, and resonance, which are associated with frequency, the project was named hertz, after the standard unit of frequency. Drawing on the fact that everything vibrates, from the smallest atom to the furthest star and that their frequencies surround us and yet leave no imprint, hertz enables people to feel their bodies resonating to the inaudible symphony of our own planet, experience the stars singing, and see their sound made visible. Hertz's ultimate goal would aim to reconnect us to our planet and place in the cosmos. Its ancillary aims would also be to educate about the science behind the project.

In this paper, we predominantly focus on the infrasound strand of the hertz project. In Sect. 2, we will describe the science behind how the installation works and the initial feedback received on the prototype. In Sect. 3, we describe how the feedback modelled the version prepared for the hertz tour around the UK. Section 4 discusses the accessibility considerations for the project and tour. Section 5 discusses the hertz set-up at each of the three UK tour locations. In Sect. 6 we review the feedback from the public from the tour. In Sect. 7, we discuss the collaboration between the artist and the scientist. The project findings are summarised in the conclusions in Sect. 8.

To create an immersive experience where modified infrasound is played through a transducer, infrasound recordings which had captured the acoustics of the natural world were needed. In this section, we describe how infrasound is measured and how the infrasonic recordings used in the hertz project were acquired. We will then describe the prototype set-up and how the infrasound recordings were processed to create an immersive experience.

Following the running of the prototypes at the venues, shown in Table 1, and the positive feedback from the public, a tour was commissioned which would see hertz being exhibited to the public at three places across the UK. It was realised that, if the installations were to tour, further development would be needed. The first extensive upgrade was to increase the amount of furniture that vibrated, allowing more people to experience the infrasound vibrations. The second was to upgrade the software that played the infrasound through the subwoofer and transducers. This was (a) to make it stand-alone, meaning minimal operator input, and (b) to configure the software to play the infrasound recorded at the locale of the installation in real time. The first part of the work was to replace the wheelchair and attached transducer with more rigid furniture. A steel garden bench and a chair which conducted vibrations well were each fitted with a transducer and linked to the existing subwoofer and playback system. The second part, overhauling the playback system, involved replacing the laptop PC, shown in Fig. 5, with a small, stand-alone computer (a Raspberry Pi) so it could be easily concealed. The INFRA20 infrasound sensor's cable was extended so it could be placed outside whilst being connected to the Raspberry Pi. Further to this, the Raspberry Pi was configured to obtain data from the infrasound sensor, process it, and play back the processed infrasound signal in real time through the subwoofer and transducers. This allowed the real-time infrasound of a location to be experienced. As computer peripherals such as a mouse, keyboard and monitor would detach from the aesthetics of the installation, the Raspberry Pi was configured to run in a “dead head” mode, meaning that a graphics user interface was not needed and any settings could be altered solely through keyboard commands. The Raspberry Pi was also configured to begin the real-time acquisition of data on start-up, further minimising operator input.

It was important to all involved in the project that accessibility was incorporated, where possible, from the start, particularly regarding physical access and the interpretation of hertz. From the outset, accessibility considerations, such as wheelchair access to buildings at the University of Reading, allowed Robson to have initial discussions with Marlton. Research, development, and construction inevitably needed to be done in accessible venues and was done at Robson's studio, the University of Reading, and at the 101 Outdoor Arts Creation Space, Newbury, where the finalised version of hertz was constructed.

The furniture used to transmit the infrasound vibrations of the location in real time for the tour were chosen, not only for their conductive qualities and ability to be used outside, but for their sturdiness. The highest seat possible, of this type of furniture, was sourced, allowing it to be sat on easily. In addition to the two benches, a chair with arms was used for visitors who needed more support. During the development phase, the transducers could be transferred to another participant's wheelchair to allow them to partake in the experience without the need to leave their chair. The volume of the sound emitted from the subwoofer was set relatively high for impact and so that visitors could feel it in the air pressure changes and in their bodies. Care was taken not to exceed each venue's health and safety guidelines. The subwoofer was placed in each venue where it was easy to touch and get close to, so that visitors could feel the vibrations and feel the gusts of air pumped out by the speaker as it amplified the sound. Figure 7 shows a deaf visitor touching the subwoofer to experience the processed infrasound.

Physically, all venues used during the tour and described in Sect. 5 had the minimum of wheelchair access, with accessible toilets and lifts. We The Curious, where hertz was installed for three months, had comprehensive access, with detailed information on their website including a virtual accessibility tour called “GoVirtually” that is designed to help people with physical and cognitive disabilities. Guidance from Giraud (2015) was used when creating on-site and online information material for hertz, such as using 14 point sized fonts. For events where the artist or collaborators held discussion sessions, a British Sign Language interpreter could be requested, and subtitles were added to the video made of hertz at the Oxford Science and Ideas Festival (Oxford IF) described in Sect. 5.

Robson is a keen advocate of physical and interpretative access. Her work, at times, plays with more than one sensory aspect; this is an aesthetic decision and does not stem from a deliberate intent to make the work more physically accessible per se. However, hertz enhances accessibility for audiences in that one can both feel and hear the processed infrasound.

The tour of hertz occurred at three tour locations, namely the Oxford Science and Ideas Festival, Tramway, Glasgow, and We The Curious at Bristol between October 2018 and February 2019. This section describes the format and set-up of hertz at each location.

As discussed in Sect. 5, there was the opportunity for participating members of the public to leave feedback on flip charts or post cards. Whilst there was much audience participation with the piece, feedback participation varied from venue to venue; like participation, providing feedback was optional. Here we will briefly describe the kinds of feedback received at each venue and then concatenate all the feedback together to see the overall impression the piece had on the audience.

In this section we will focus on how the art–science relationship developed over the duration of the project. At the first meeting between Marlton and Robson, Marlton presented a brief introduction on infrasound with much explanation of the terminology through diagrams. Robson, in turn, explained her background in contemporary art and her interest in sound and the invisible and inaudible frequencies of the Earth and cosmos. The discussion then turned to what each party wished to obtain from a potential collaboration. For Marlton, it was to create an outreach activity which used infrasound, highlighting its use in weather prediction, and to highlight the archives of infrasound that are recorded constantly across the globe. For Robson, it was the potential to further explore her research interests in the natural sciences, inspired by her father, Michael Robson, who was a plant physiologist, to develop ways that could be used to make inaudible sound tangible using the latest scientific research. Robson constantly asked questions and Marlton would answer in full in what sounded like a different language; equally, Robson would talk about concepts in contemporary art and receive blank looks from Marlton. However, a positive attitude by both led to their thinking about simplifying the terminology and different ways of explaining concepts. By the end of the first meeting, a rough concept idea had been conceptualised of a piece that could connect people to the hidden resonances of our planet. The initial discussion stages have similarities with art–science collaborations such as MacMullen (2005), where initially the artist is finding out as much about the scientist's research as possible.

The next stage of the project involved visiting each other's working environments. Robson visited Marlton's research institution, and Marlton visited Robson's studio to construct some of the early prototypes and work on the signal processing. It was here that differences in art and science projects differed. Webster (2005) describes that many art–science collaborations come about through an artist being hosted at a research institution. Here, Robson had independently acquired research and development funding from Unlimited, a commissioning organisation who fund artists who have faced access barriers in their careers. The caveat of the grant was that the funding be used to explore proof of concept ideas that need not produce a final working prototype. It is extremely important that artists are able to have time and space to do this and that they are able to follow lines of inquiry and experiment with ideas and concepts without the fear of failure or the constant pressure to produce a fully fledged artwork which stifles creativity and ambition. Marlton said this was an appealing prospect, especially coming from a background where funding is often dependent on proof of concept and goal-oriented outcomes. Indeed, there were no guarantees that what we conceptualised would even work, and the funders understood this.

It would be easy to assume that the relationship between Marlton and Robson was that Marlton was a provider of technology for a preconceived concept developed by an artist. However, this would deny the journey that Marlton and Robson embarked on and the ideas that developed for the demonstrations during the research and development phase and the tour.

At first inspection, it would seem that the project followed a generalisation, outlined in Webster (2005), in that the scientist would provide a technology and the artist would work on curating the conceptual development and communicating the project to venues and the public. For hertz, there are some similarities. Marlton led on the technology development side but was more than a technology provider. For example, he suggested that transducers used for gaming could be used to enhance the physical experience. In addition to this, Marlton spent time testing the effects of different infrasound filtering parameters and partaking in conversations about how different configurations may alter the authenticity of the final processed output. Thus, he took on a more creative role. Robson, having little to no experience of the technology involved in the sensing of infrasound, learnt from Marlton what he thought was and was not possible with the technological aspects; this in turn informed the development of concepts and what may be possible in the final tour version of hertz.

Working on the project over 2 years enabled Robson and Marlton to hone their methods of communicating complex ideas with each other. Understanding of each other's subject areas developed gradually by being around each other and picking things up; it was an osmosis of knowledge aided with the use of diagrams and developing metaphors for concepts. Towards the end of the project, Robson had a deeper understanding of infrasound, its uses and potential – not only for future artworks but for research – and its current applications. Marlton had a greater understanding and appreciation for contemporary art, particularly interactive art, and its potential to make complex scientific ideas not only understandable but exciting, relevant, and meaningful.

Jeffreys (2018) states, “When it comes to collaboration, there is a danger that generalising about scientists as [being] rational, institutionalised and ends-oriented versus artists [who are] emotional, free, process-driven can risk accentuating disciplinary stereotypes. Or, conversely, that trying too hard to find commonalities can lead to simplistic platitudes about `creativity'. People are more than the discipline they represent.” During this project, such a generalisation as this was avoided, and we felt that the metaphorical wall that exists between the two disciplines was overcome, similar to case studies discussed in Leach (2005).

It became clear that certain methodologies were recognisable to both Robson and Marlton. Both worked with flexible forms of praxis-based research, which could be defined as a form of critical thinking, and comprises the combination of reflection and action taking. This reflection and action taking is demonstrated in Sect. 2.3, when it came to assessing how to best process the infrasound from feedback during the prototyping sessions. Ultimately, the project had similarities to that concluded by Stewart (2003) who stated:

The research function of developing and extending knowledge is to be judged on the products of that research. In the same way that a learned paper is evidence and coherent argument for all the processes that preceded it, laboratory or speculative, the finished work of art is the culmination of the theory and practice of the discipline. Based essentially on investigative, exploratory, speculative, or analytical processes, the outcomes are a result of synthesising the problematics of the discipline. Like the best research in any field, it is expected that creative work will comply with the defining characteristics.

It was previously highlighted at the start of the project that Marlton and Robson, whilst being positive, were unfamiliar with each other's subject areas. We reflect here on how these attitudes have changed. In an interview with Liz Hingly for the University of Birmingham's Phyart website, Robson stated:

The project [hertz] is the first time I have worked in depth with scientists. Overall, it has given me an understanding [of] and deeper appreciation for the ways artists and scientists can collaborate, affect each other's work, and learn each other's language. This can only be achieved through a commitment by the artist to meaningfully engage in scientific research and for the scientist to trust in the artist's ability to create something that communicates on both an artistic and scientific level. Finding a successful working partnership, where both parties meet on a common ground, is not easy. Simultaneously, the partial mystery in each other's processes of research and creation motivates the relationship. … My main motivations are to make an outstanding artwork with the use of cutting-edge science that is accessible to as many people as possible. Something interactive, intangible, mysterious, an encounter that inspires questions. I do not aspire to be a physicist; I want to retain and share the mystery of true science.

In summary, hertz did not suffer from the generalisation that the scientist is a technology provider and the artist is the curator of the given technology. Here, that boundary did not exist, and the scientist had a large input into the creative part of the project. Likewise, the artist took an extensive interest in understanding the science involved and was able to input into the design of the technology developed for the project. This was achieved by having a positive attitude and an open mind to learn about completely new subject areas. When collaborating, a similar methodology of action taking and reflection provided a framework for creativity. In addition to this, having a grant that was not issued by a research institution, as is commonly done, allowed the development of hertz to take a more dynamic route, where creativity was prioritised over the need to produce a finalised artwork by a deadline. For Robson, hertz allowed her to gain experience in art–science collaboration that can be applied to future art–science collaborations. For Marlton, his knowledge of contemporary art has increased, along with seeing the benefit of working with artists in the future to boost the visibility of research. It has also opened new avenues in problem solving.

Here, an art installation named hertz, which was aimed at allowing people to feel reconnected with the environment and was to be used for helping to describe the science of infrasound, was created. This was achieved through a successful research and development phase that allowed ideas to be developed. The subsequent three-stop tour of the UK allowed hertz to be exhibited in an accessible way to the public. Analysis of the feedback received showed that most participants found a deeper connection to Earth and the environment after partaking in hertz. For a future tour of hertz, or a variation thereof, an installation could be set up in an underground station where large sections of the space vibrate and shake. hertz also demonstrates that there is considerable potential for outdoor structures and street furniture to have transducers attached to them, widening opportunities for experiential art. In addition to this, more thought is needed into how to communicate the science behind the installation whilst not detracting from its aesthetic.

The collaboration between the artist and scientist worked well. The key to a successful collaboration was to keep a positive outlook and break the generalisations of scientists being a technology provider and the artist being the curator of the technology. Here, both the artist and scientist broke the metaphorical wall using common methodologies between the two subject areas, which led to a more creative output. The experience of the collaboration has improved each individual's working practice. For the artist, it allows more confidence in forming new art–science collaborations for future works. For the scientist, it allows new perspectives for problem solving. The experience documented here can be used as a model for future art–science collaborations. The authors encourage more science, technology, engineering, art, and maths (STEAM) projects (Seggara et al., 2018) based on their experiences here.