A traditional sculpture, however large, is still fundamentally an object: something placed within a room that a viewer walks around and looks at from the outside. Installation art, a major strand of contemporary sculptural practice that developed particularly from the mid-twentieth century onward, works differently — it treats an entire space, not a single discrete object within that space, as the artwork itself, often designed specifically so that a viewer physically enters and moves through the piece, making their own bodily presence and movement inside it a genuine part of what the artwork actually is, rather than something incidental happening near it.
The boundary between the artwork and its surrounding space collapses
In a conventional sculptural display, there's a fairly clear boundary between the artwork and the room housing it: the sculpture is the art, the room is just where the art happens to be shown. Installation art deliberately dissolves that boundary, using the walls, floor, lighting, sound and overall spatial arrangement of an entire room, or sometimes several connected rooms, as integral elements of a single unified work, rather than as a neutral backdrop the sculpture is merely placed inside. This often means an installation is site-specific in a way an individual sculpture typically isn't — designed for, and sometimes only fully meaningful within, one particular space, and not straightforwardly transportable to a different gallery the way a freestanding sculpture generally is.
The viewer becomes a genuine participant, not just an observer
Because a viewer physically enters and moves through many installations, rather than standing at a distance and observing a fixed object from outside it, their own choices about where to walk, what to look at first, and how long to linger become part of how the work is actually experienced, meaning two different viewers can genuinely have quite different experiences of encountering literally the same installation, depending on the specific path each of them happened to take through the space. This participatory, spatial dimension is a large part of what distinguishes installation art conceptually from earlier sculptural traditions, which generally assumed a single fixed vantage point, or a small number of them, from which the completed work could be properly appreciated as a whole from outside.
What we're still unsure about
The historical development of installation art as a distinct practice, and its core conceptual departure from treating an artwork as a discrete object separate from its surrounding space, are well documented in art history. What remains more genuinely a matter of ongoing critical and curatorial debate is how installation art should be preserved, documented and exhibited once its original specific site, materials or even the artist themselves are no longer available — since a piece designed around one particular room's exact dimensions, lighting or even its specific historical context resists being straightforwardly reproduced or preserved the way a durable physical sculpture in bronze or stone generally can be, a genuinely unresolved practical challenge museums and conservators are still actively working through rather than one with an agreed, standard solution.
This sits inside Contemporary Sculpture & Installation Art, one of seven topics in Sculpture, one of five domains in Art, one of seventeen subjects the app can quiz you on.