UV a scam?

[bait dunker]

I was getting my eyes checked the other day and asked the eye doc about Ultra Violet light under water. He chuckled and told me that UV light can't penetrate water well. He explained that UV is reflected by water, which is why we get sunburned on the water so easy. He also told me that the UV spectrum closely follows the normal color spectrum as far as penetration, but on a much shallower scale. He said the UV blues and greens penetrate the deepest, at about 3 feet! I explained that I had UV reflecting flatfish, and he agreed they work. "they caught you didn't they?" he explained that at a depthgreatwr than 3 feet, they just appear the color they are painted, with no UV enhancement. He seemed to be knowledgable about it. What do you think? Did I waste the extra money on UV enhanced lures?

[Spade]

We all agree that greens, blues and purples penetrate the deepest right? Because they have shorter wave lengths than reds and oranges...UV is even shorter than they are.


Your eye doc is a boob.


http://www.nas.nasa.gov/About/Educat...radiation.html
"For example J.Regan's work at the Florida Institute of Technology used human DNA to find that genetically significant doses of solar radiation could penetrate as far as 9 feet into non-turbulant ocean water."

More fun:
http://spg.ucsd.edu/people/Greg/Publ...ov_UVSpace.pdf

See Figure 2 on page 4. Depth expressed in meters and wavelength. The SHALLOWEST it goes is 5 meters....that's at least 25 feet, that's at a solar zenith angle of 60 degrees.

Figure 2 shows the wavelength dependence of the penetration depth defined as a depth at which the total downward irradiance is reduced to 10% of its surface value. The penetration depth was calculated for different SZAs and chlorophyll concentrations. The chlorophyll dependence of the penetration depth is obvious: It closely follows the total absorption of seawater because the diffuse attenuation coefficient is mostly determined by seawater absorption while scattering plays an insignificant role because of the strong anisotropy of seawater scattering. The SZA dependence of the penetration depth is less obvious. Variations of the SZA cause a change in the angular distribution of light incident on the ocean surface. The change in the angular distribution of light leads to a change in the diffuse attenuation coefficient because the irradiance attenuation depends on the angular distribution of light penetrating into the ocean.23 This dependence is relatively weak; however, it exists.

[Arctic]

For very high energy photons, like deep uv, gamma, and x-rays, the energy of the photons is so large that it does not match any electronic energy transitions in matter, so the photons are not at all absorbed, but rather penetrate very deeply. Now the deeper you get the more uv gets absorbed, and the spectrum can get shorter, or smaller is a better word, until the water density gets so massive it envelops up to 85% of uv radiation... at 1,000 plus feet. Enough water could absorb x-rays too!

They use uv light to treat water too. They use uv because it can very easily commute through water molecules. Which would be counterintuitive to what your eye doc said.

The main purpose of uv lures... the be different. Different is good! Keep the lure! You were not duped by the fishin industry!

[steelhead_stalkers]

Moral of the story, don't take your doctor fishing!!

[bait dunker]

While it seems the doc wasn't entirely correct, it appears he was correct in principal. Just doing my own homework, I found: http://wiki.answers.com/Q/Do_the_sun...to_what_degree "The sun's rays do penetrate water, but each color penetrates to a different extent. Generally, the more energetic colors, those at the upper end of the color spectrum, the blues and violets, penetrate deeper. The lower frequency wavelengths, the oranges and reds, peter out at shallower depths. But these generalities will vary, as the ability of light to penetrate water is affected by what is in that water. Red light is absorbed within 15 to 20 feet, while blue light can make it down as far as 200 feet or more (this is why the deep water appears bluish), depending on the clarity and turbidity of the water.

Snorklers near the surface need to practice caution, as they are prone to burn. Wear a t-shirt or dive skin, or wear waterproof sunblock. UV lamps are used to drive reactions and/or sterilize water in municipal water systems. In such systems, if the water is clear, UV-B will travel many centimeters before its intensity is too low to make a significant effect."

http://www.newton.dep.anl.gov/askasc...0/phy00502.htm

Question - Can UV rays penetrate water? For example: Standing waist
deep in a pool of water, will my legs be protected as my upper body burns?
---------------------------------------------------------------------------
Water does scatter U.V. radiation, and the surface of the water will
reflect a part of incident U.V. radiation so your legs are more protected.

Vince Calder
================================================== ============================
Terry,

Sunlight's UV component will not penetrate water very far. Indeed, if
overexposed, the parts of you that are above water will burn -- even faster
than if you were on dry land because the surface of the water reflects the
radiation. As a result, you get hit with the direct and well as the
reflected rays.

Regards,
ProfHoff 416
================================================== ============================
U.V. radiation (depending upon the wavelength) penetrates water to some
extent, but not far, because various components in the water absorb the U.V.
radiation, and in addition water scatters the U.V. radiation. So, YES, your
exposed upper body will burn more quickly than your legs submerged in water.

Vince Calder
================================================== ============================
while I realize these two links aren't very scientific, it seems the consesus, even with Spades links is that the UV light doesn't penetrate very deep. I'm all about trying something different, but UV painted lures and sprays do seem to be a a reach from what I'm reading.

[Spade]

while I realize these two links aren't very scientific, it seems the consesus, even with Spades links is that the UV light doesn't penetrate very deep.

Okay so light is radiation right? Lets look at the possibility he was talking specific (as my first link does) about UV-B.

The answer for sure is in the second link that I provided that UV can and does penetrate upwards of 60 meters. The problem is it's a very scientific paper and I'm not currently in the mood to attempt a translation.

[bait dunker]

Gotcha, thanks for pointing that out.

[spactrukn]

All of this scientific high speak is giving me a headache....

[Chinook SSSF]

Yay for grey areas and varying conditions! hehe I think it was interesting to see the idea of UV light explained from 3 different angles of thought.

I would be all for trying UV based lures if any of my friends could tell me it was "more" effective, although I am not sure I could be talked into paying extra for it...

[steelhead_stalkers]

We have had quit a few instances where UV out fished the same type of lure by a large margin and other times where they work the same. UV has never been out fished by none UV in our testing so it seems the added UV does not hurt but only enhances a lure or bait. For me I like knowing that I have every angle covered on what the fish is going to see (great colors, UV, and scent).