5 ms·
Aside: what is the "speed of smell"? I assumed it would slowly diffuse across the room, but when one of my kids has a dirty nappy/diaper it is like a lightning
by mattlondon 4y ago
Aside: what is the "speed of smell"? I assumed it would slowly diffuse across the room, but when one of my kids has a dirty nappy/diaper it is like a lightning bolt in my nostrils from the other side of the room.
- liquidise 4y agoThis is a great question i'd love the answer to as well. My intuition tells me the speed particles passively would move through the air would be limited roughly by the speed of sound? That feels like a hard upper bound, though?
- version_five 4y agoIt's governed by diffusion. There is an equation ( Einstein eq. I think) that says something about the average distance diffused being proportional to sqrt(time) and a diffusion coefficient which depends on what is diffusing and in what medium. the units of the diffusion coefficient are in m^2/sec because of the square root dependence but it's sort of an analog to the speed. Delta x = Sqrt(6Dt) in 3d It's based on brownian motion leading to a gaussian distribution of distances travelled
- zasdffaa 4y agoIn still air surely so, where people are I guess there's a lot of convection.
- deleted 4y ago[deleted]
- 7373737373 4y agoI've wondered something similar, in particular about what happens when I open the window of a closed room. How fast do the gas compositions reach equilibrium again? Haven't found an answer yet even for very simple assumptions, e.g. 1m³ cube room, 0.01m² window.