  The viscous behavior of fluids can be observed in numerous everyday
situations. Therefore, it is reasonable to assume that people, since they are
usually not specialists in fluids' flow behavior, possess na\"ive conceptions
about the viscous behavior of fluids. These conceptions more or less deviate
from corresponding scientific explanations. Qualitative studies with preschool
children and secondary school students from Germany have already identified
various na\"ive conceptions about the viscous behavior of fluids (e.g., that
the density or stickiness of a substance explains its viscous behavior). Within
the present study, we explore the question of whether similar na\"ive
conceptions can also be found among adults around the globe. To this end, based
on previous research, an online questionnaire was developed to survey adults
worldwide regarding their na\"ive conceptions about the viscous behavior of
fluids. The survey was conducted anonymously, online, and voluntarily in spring
2023; participants were recruited via SurveySwap. A total of 406 adults from
all regions of the world (primarily Europe and North America) participated in
the survey. In this paper, we report and discuss the main findings of this
online survey.
