Cycling Mob: Road Cycling, Mountain Biking and More - View Single Post

07-14-2004, 01:24 AM

Also, hot air is less dense. Convert temperature to Celcius (-32 * 5/9)
add 273 to convert to Kelvin. Take 273 and divide by the Kelvin
tempature to get this ratio. EG 30 Celcius (86 Ferenheit) has a ratio
of 273/373 dry air density (0% humidity). Also, warmer air can hold
more water vapor as tempature rised. A dew point of 65 degree Farenheit
means the air, if cooled to 65 F, would be at 100%. Warm the air to 90
with that days sun and the humidity is 60% with the same amount of
moisture in it. Take it to 212 F 100 C and 100% humidty means 100%
water vapor, 0% nitrogen, 0% oxygen. There are water vapor tables that
can tell you at what tempatures 100% humidity means as far as percent
water and percentage air.

David Kerber wrote:
>
> In article <40f3f18a$0$21383$4d5ecec7@reader.city-net.com>,
> tombates@city-net.com says...
> > On a day with a high humidity (everything else being equal) would it take
> > more energy to bike a certain distance than on a day with low humidity since
> > a person has more resistance from the moisture.
> >
> > Thanks
>
> Water vapor is *less* dense than air (molecular weight 18, vs Nitrogen
> at 28 and Oxygen at 32), so the air resistance would likely be less on a
> humid day. This causes big problems for propeller-powered airplanes in
> the tropics if they aren't equipped for it.
>
> --
> Remove the ns_ from if replying by e-mail (but keep posts in the
> newsgroups if possible).

07-14-2004, 01:24 AM	#17 (permalink)
Mike Schwab Posts: n/a	Re: Humidity affect on biking speed Also, hot air is less dense. Convert temperature to Celcius (-32 * 5/9) add 273 to convert to Kelvin. Take 273 and divide by the Kelvin tempature to get this ratio. EG 30 Celcius (86 Ferenheit) has a ratio of 273/373 dry air density (0% humidity). Also, warmer air can hold more water vapor as tempature rised. A dew point of 65 degree Farenheit means the air, if cooled to 65 F, would be at 100%. Warm the air to 90 with that days sun and the humidity is 60% with the same amount of moisture in it. Take it to 212 F 100 C and 100% humidty means 100% water vapor, 0% nitrogen, 0% oxygen. There are water vapor tables that can tell you at what tempatures 100% humidity means as far as percent water and percentage air. David Kerber wrote: > > In article <40f3f18a$0$21383$4d5ecec7@reader.city-net.com>, > tombates@city-net.com says... > > On a day with a high humidity (everything else being equal) would it take > > more energy to bike a certain distance than on a day with low humidity since > > a person has more resistance from the moisture. > > > > Thanks > > Water vapor is less dense than air (molecular weight 18, vs Nitrogen > at 28 and Oxygen at 32), so the air resistance would likely be less on a > humid day. This causes big problems for propeller-powered airplanes in > the tropics if they aren't equipped for it. > > -- > Remove the ns_ from if replying by e-mail (but keep posts in the > newsgroups if possible).