The things that make you feel dumb

[Tuckahoe]

There are some mornings that I am reminded how dumb I am.

Got a chance to get out this weekend and use the hammock.

image_zpsa807302b.jpeg image_zps6cccb43a.jpeg

Everything was great and I had two awesome nights sleeping. My only issue seemed to be an excessive amount of condensation on the tarp. Setting out to find out why reminded me that I should have paid better attention in Mr Regan's science class.

Found this article in my search -- http://johncwalton.com/WindowOutdoor...0Radiation.htm.

[Wise Old Owl]

I'm stumped - if the photos match the moment - why the condensation? if you don't touch it .. no worries.

[Tuckahoe]

That's just it, I didnt think there should be condensation. But there was and I wanted to know why. Though I'll admit that I will need to read it a few more times, the article explains why.

Tarps work by having high rates of ventilation which keeps the moisture content of the air under the tarp nearly the same as in the ambient air. Good ventilation and blocking ground moisture with a ground cloth help, The pervasive common wisdom (which is wrong) is that with great ventilation one should never see condensation on a tarp. Unfortunately the infrared radiation imbalance which occurs on clear, calm nights causes the tarp fabric temperature to drop below the air temperature - leading to condensation even in the absence of additional moisture sources such as human breathing and sweat. Ventilation will not always prevent condensation.

[Dogwood]

The things that make you feel dumb

Quantum Mechanics and String Theory eggheads that suddenly turn science into something more akin to a profound esoterical philosophy lecture.

[wornoutboots]

Foggy Night??

[Tuckahoe]

No it wasnt foggy at all. It was down to 46º each night, very clear, calm and beautiful.

[Catnip514]

I have noticed this happening when I have no tree cover. I assumed that moisture was created in the air with the changing temperatures and with no tree cover it found its way to my tent/tarp. Isn't this basically like dew in the morning on the grass or am I confused?

[Blissful]

Happens to me too with no tree cover and also a windless night

[wnderer]

I have noticed this happening when I have no tree cover. I assumed that moisture was created in the air with the changing temperatures and with no tree cover it found its way to my tent/tarp. Isn't this basically like dew in the morning on the grass or am I confused?

That is correct and what the link in the original post was trying to explain. Condensation will occur if the temperature of the fabric drops below the dew point. There are basically three (non chemical) heat removal mechanisms; conductive: like sticking your tongue on the cold metal pipe; convective: circulating air carries away heat and radiative: heat as invisible light. If you used night vision goggles you would see everything around glowing. That glowing carries away heat and cools things down. If the sky is overcast or you're in the shade, those things are reflecting some of the light back and the tent stays warmer than if open to the night sky which is the darkest coldest thing around.

[Wise Old Owl]

I am sure you mistyped (misspoke) - night vision makes weak light brighter, FLIR vision or Infared cameras interpret the heat signatures. I use them to find termites inside walls. Owls in trees etc,


I have both - and my night scope doesn't glow. Maybe yours is different.

[wnderer]

I am sure you mistyped (misspoke) - night vision makes weak light brighter, FLIR vision or Infared cameras interpret the heat signatures. I use them to find termites inside walls. Owls in trees etc,


I have both - and my night scope doesn't glow. Maybe yours is different.

Yes you're right. I really don't know too much about night vision and I mixed them up.

[Wise Old Owl]

its all good... no worries.

[Alligator]

There are some mornings that I am reminded how dumb I am.

Got a chance to get out this weekend and use the hammock.

image_zpsa807302b.jpeg image_zps6cccb43a.jpeg

Everything was great and I had two awesome nights sleeping. My only issue seemed to be an excessive amount of condensation on the tarp. Setting out to find out why reminded me that I should have paid better attention in Mr Regan's science class.

Found this article in my search -- http://johncwalton.com/WindowOutdoor...0Radiation.htm.

Well if it makes you feel any smarter, I forgot my tarp the first time I used a hammock. And I didn't camp at a shelter that evening. Fortunately no rain.