Liquid Slider: Evaluating the Experience of Liquid on a Touch Input Surface

We investigate an unconventional user interface (UI) material, water, and how applying it to a finger-touch based input affects the user experience (UX). We compare the use of touchscreen, mechanical and liquid covered sliders, and three different approaches of how water is applied to the surface of the slider. The salient findings of our user study (n=25) show that liquid changes the perception of the slider control making it more hedonic and experiental. When interacting with water, users prefer larger and more free-form gestures, and factors such as depth and temperature of the liquid affect the experience. Our work provides information for interaction designers focusing on user experience, unconventional materials for interactive systems, aesthetics, and calm UIs.