Epsilonballs

Epsilonballs are a class of small, soft-shelled spheres used as standardized test objects in laboratory, educational, and research settings. They are typically made from elastic polymers such as silicone or polyurethane and can be air- or liquid-filled, enabling a tunable density and elastic response. The term is used across disciplines to refer to spheres designed for reproducible mechanical and acoustic interactions.

Physical properties vary by variant. Typical diameters range from 0.5 to 3 centimeters. Densities span roughly 0.5 to 1.3 g/cm3, depending on core fill. Shell thickness is small relative to overall size, and the material’s stiffness can be tuned by formulation. Surfaces may be smooth or microtextured, and some variants include magnetic inserts, conductive layers, or color markings for tracking or manipulation.

Manufacturing generally involves casting or mold-curing an elastomer around a removable core, followed by curing, demolding, and surface finishing. Quality control commonly includes dimensional measurement, density determination, and bounce or deformation tests to ensure consistent mechanical behavior.

Applications cover educational demonstrations of buoyancy, momentum exchange, and elastic collisions, as well as research uses. In acoustics and ultrasound, Epsilonballs serve as soft-mensor probes or scattering targets. In soft robotics and haptic devices, they provide compliant contact and programmable damping. Arrays of Epsilonballs can be used to study packing, jamming, or the behavior of granular-like materials under controlled conditions.

Safety and handling are standard for laboratory elastomers. They are intended for use in non-sterile environments and should not be ingested. Proper storage away from extreme heat and prolonged ultraviolet exposure helps preserve elasticity and surface integrity.