Horsetail Fall (Yosemite) picnic area on the north road leading out of Yosemite Valley east of El Capitan. Horsetail Fall (Yosemite) Horsetail Fall, located in Yosemite National Park in California, is a seasonal waterfall that flows in the winter and early spring. The fall occurs on the east side of El Capitan. If Horsetail Fall is flowing in February and the weather conditions are just right, the setting sun illuminates the waterfall, making it glow orange and red. This natural phenomenon is often referred to as the "Firefall", a name that pays homage to the manmade Firefall that once took place in Yosemite.
Marsh funnel time of 100 or more seconds. While the most common use is for drilling muds, which are non-Newtonian fluids, the Marsh funnel is not a rheometer, because it only provides one measurement under one flow condition. However the effective viscosity can be determined from following simple formula. μ = ρ (t - 25) where μ = effective viscosity in centipoise ρ = density in g/cm³t = quart funnel time in seconds For example, a mud of funnel time 40 seconds and density 1.1 g/cm³ has an effective viscosity of about 16.5 cP. For the range of times of typical muds