Go Back   Physics Help Forum > High School and Pre-University Physics Help > Thermodynamics and Fluid Mechanics

Thermodynamics and Fluid Mechanics Thermodynamics and Fluid Mechanics Physics Help Forum

LinkBack Thread Tools Display Modes
Old May 2nd 2014, 02:30 AM   #1
Junior Member
Join Date: May 2014
Posts: 1
Unknown Phenomenon

Hey guys, i have a presentation to do on a chosen topic that relates in some way to fluid mechanics. I have chosen mine to be based on whitewater kayaking since im enthusiastic about that. Would anyone be able to give me some info about how and why you can land off some waterfalls flat and others you have to 'pin it'. I guess this is a similar question to why do they have a machine blowing bubbles in the water for those big cliff diving competitions? Is it to do with surface tension or what's going on here? CHeers
Stomper is offline   Reply With Quote
Old May 2nd 2014, 04:07 AM   #2
Senior Member
MBW's Avatar
Join Date: Apr 2008
Location: Bedford, England
Posts: 668
The amount of air bubbles in the water reduces it's effective density,
essentially are you hitting solid water or a foam.

The more air bubbles the lower the density, thus the lower the buoyancy forces trying to stop you going under, thus the lower the impact.

At the extreme, there could be so much air (and so little water) that you sink.
(It has been suggested that releases of methane bubbles from the ocean floor have been responsible for boats sinking).

I think that the bubbles in diving are primarily to make the water surface more visable, I don't think the volume of air involved is intended to make a significant difference to the water density.
MBW is offline   Reply With Quote

  Physics Help Forum > High School and Pre-University Physics Help > Thermodynamics and Fluid Mechanics

phenomenon, unknown

Thread Tools
Display Modes

Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
Arcing ground phenomenon in Isolated neutral system titangsu Advanced Electricity and Magnetism 0 Aug 7th 2014 09:17 AM
Can a double oxidation phenomenon generate an electric current? sorin Electricity and Magnetism 2 Nov 27th 2013 11:59 AM
problem in photoelectric phenomenon mido22 Energy and Work 0 Aug 18th 2013 09:08 PM
Volume of an Unknown Object, given the denseties of 2 liquids Stratomire Thermodynamics and Fluid Mechanics 1 Dec 4th 2008 09:00 PM
two unknown forces disclaimer Equilibrium and Elasticity 8 Oct 19th 2008 03:44 AM

Facebook Twitter Google+ RSS Feed