Hobie Science :: Why is The Sky Blue “RePost”

School is almost out for the summer, and you are waaaaaaay behind on your papers!!! Have no fear, Gary Larson is here to hook you up with all the research you need to answer the question “Why is the Sky Blue??”

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For this weeks science blog we will leave the oceans and look at what makes the sky appear blue. And no, it is not because the ocean is reflecting the color of the water into the sky. (Ed Note: Full disclosure, I have always thought this to be true before Gary explained it to me)

In order to understand what makes the sky blue we must first understand the basics of sunlight and color. I recently read a fascinating article about a young Isaac Newton’s early experiments with light waves. The year was 1665 and a 23 year-old Newton was home from school due to the plague. Newton confined himself to his room and began experimenting with a prism. He closed his blinds and cut a small hole allowing a small stream of light to pass through. Newton then held a prism into the beam of light causing the light to scatter, ultimately casting a rainbow upon his wall.

Prior to this experiment it was widely believed that sunlight was white in color and therefore could not be muddied or changed. What Newton proved was that sunlight actually consisted of all the colors in the visible light spectrum together. There were many people who criticized this experiment, mostly due to religious credence, claiming that white light was holy in nature and could not possibly be made up of colors, and that the prism itself contained the colors of the rainbow.

Subsequently Newton devised a second experiment consisting of a second prism. Remember, this was in 1665 and a prism was not easy to come by. So, Newton held the second prism into the blue portion of the rainbow allowing only blue light to pass through and just as he had presumed, only blue light was cast against the wall.

Visible light is part of the electromagnetic spectrum consisting of the electromagnetic wavelengths between about 400 and 800 nanometer. For reference, one-nanometer is one-billionth of a meter.

As we can see from the electromagnetic spectrum above, the colors containing the highest amounts of energy, thus the shorter wavelengths, are violet and blue. When sunlight passes through the atmosphere these higher energy wavelengths scatter, being absorbed and reflected off the molecules that makeup our atmosphere causing the sky to appear blue. In space, where there is no atmosphere, the light is not being scattered off of molecules therefore appearing black.

Why, then, does the sky not appear violet? This has to do with how our eyes work. We have three different light receptors in our eyes called cones. They respond most strongly to the colors blue, red, and green. Therefore, although violet and blue wavelengths are being scattered in the atmosphere our sensory system, using the blue cones in our eyes, tell our brain that the sky  is blue as it is the strongest wavelength stimulating the blue cones.

So this week when you are at the beach, looking up at the blue sky, you will have a basic understanding of why you see blue, but stick around until sunset and the orange and red sky will open up a whole new set of questions. This will be discussed next week.

-Gary Larson

Hobie Surf :: Let the Summer Water and South Swells BEGIN!!

…Oh summer water…. glassy, greenish blue, glorious, warm, all enveloping, salty, delicious summer water. And, you too, early summer South Swells, with your long lines, pick and choose corners, head high, speedy, down the line, shining like a diamond waves*. I can’t get enough of you. You could come and stay year round and I would never burn out on your allure. Is there anyone who doesn’t love you? Is there anyone who doesn’t immediately want to call in sick to work when they see your pending arrival on the surf report…?

Donavon Frankenreiter…. glassy summery love.

This is a magic time of year. May, much like September, has all the textures, sounds, and feels of summertime with none of the crowds, long lines, lack of parking, clogged up freeways, and even more clogged up surf breaks. You know, as year round residents of the Southern California, we all have a teeny “nnnoooooooooooooooo…. wwhhhhhyyyyyyy….. how are there SO many of you, where did you all come from, and how did you all coordinate to show up at exactly the same time on exactly the same date???” mentality when it comes to our beaches and the summer crowds… (ok, I’m probably exaggerating, there are at least 4 less O’s in most locals cry of No ;) ) But, right now, today, with this beautiful pre-July 88 degree day on tap, and this sizable swell in the water. This is a fine day to live at the beach. A day like today makes me remember my favorite saying about real estate prices in Costal OC.. “It’s not that the prices are high for what you get, it’s that they are not high enough for what you get.”

 

So here it is. This is our time. Before the June gloom takes over the mornings and before the train starts to drop off the visitors, this is our time. The first South Swells of summer are lighting up the coast! Parking is ample, the freeways are free, the water is warm, the surf is glorious… and it’s all ours for a few more weeks! So get down here, you local. Gt your feet in the sand, get your board in the water, get your bronze on. Bring your bbq, some wood for the bonfire, spray yourself down in Coppertone… Your beaches are waiting for you! Happy May So Cal, it’s our time… see you in the water and on the sand!

-Tracey Engelking

*Waves Explained from our friends at Magic Seaweed :: 

Waves.

In a perfect world a wave looks very simple. The height of a wave is the total distance from it’s peak to it’s trough. The period is the time, in seconds, that it takes for a first then second wave to pass the same point. In other words the time in seconds between successive peaks or troughs. Interestingly for us as surfers this number is consistently related to both a swells speed and the depth of water in which it can start to react with the seabed. This makes it something of a magic number for determining how a swell will transform itself into surf at your beach (something we’ll continue to cover in detail) and at least as important as the height of the swell.
The direction is exactly as it sounds – the direction in which the swell is heading. This is typically expressed in compass points (North, East, South, SW) or degrees (180, 270) and, while there’s no absolute convention surf forecasters tend to talk about the direction the swell is coming from. So a south swell is one that is heading from the south to the north, it could also be described as having a direction of 180 degrees.

Hobie Surf:: Board of the Week: Tyler Warren Egg Shaped Ecoboard

Sustainability.  This is our future, like it or not.  Surfer’s the world over are coming to grips with the reality that our ticket to the glide is anything but sustainable, with a few notable exceptions.  On that “black” December day in 2005 when Clark Foam abruptly and forever closed its doors the surfboard manufacturing industry as it was then known was thrust into change, for better or worse.  The scramble was on.  Hoarders, both of blanks and surfboards infested surf shops like fleas on a dog.

The End…. The broken molds of Clark Foam. Photo by: Mark Stavron of O’Fishl Fins.

At that time Extruded Polystyrene Foam (EPS) and epoxy resin had been in use, but mostly by craftsman making custom, one-of’f's.  To my knowledge it had never been put to the test in a production mode.  The process was fraught with hiderences.  It required the patience of Mother Theresa, and the tenacity of God.  Fortunately, Floridian, Greg Loher had been using and refining the stuff for some time.  Greg had formulated and was manufacturing an epoxy resin for use with EPS surfboard blanks that substantially reduced the time needed to use epoxy resins in the glassing of surfboards.  Perhaps Greg saw his financial future written on the laminators wall, but to his credit, he showed up in Orange County and unselfishly showed anyone interested the hows and whys of using epoxy resin with EPS foam.  Thankfully surfing entrepreneurs rose to the challenge and epoxy resin and EPS foam are now commonly used in the production of surfboards.

Back to the future:  Presented here for your review is a hand-shaped, eight foot egg shaped by Tyler Warren of Hobie Surfboards.  This classic double-ender is as close to a sustainable surfboard as I’ve found.  Verified as an “Ecoboard” by the non-profit organization Sustainable Surf (see sustainablesurf.org)  Tyler’s creation is a “science-based ‘benchmark’ for a sustainable surfboard,” states founder, Kevin Whilden.  Using [recycled] EPS foam, [bio-based] epoxy resin, and an inlaid bamboo veneer deck produces a surfboard that has 40% less environmental impact than a standard surfboard.

Ecoboard by Tyler Warren

The Tyler Warren, Hobie Egg, has a subtle roll through the bottom entry rocker that runs into a “vee” panel off the tail.  It’s rails, with the exception of the hard rail in the tail for maneuverability and release, are 50/50 all around.  The TW Egg comes as a rounded-pin and can be ridden either as a single-fin or a two plus one. This beauty can be used as your everyday board or as a step-up to your longboard.

To get yours, contact Andy at 949-542-3400 the San Clemente, Del Mar Avenue, Hobie Surf Shop, or at hobie.com.

-Andy Cowell

Hobie Surf: Gary Larson Unshapes a Surfboard.

The thing you have to love about the internet is that you can stumble upon hidden gems that you never knew existed… like the video below of Gary Larson “unshaping” a surfboard.

After we watched it, we pretty much decided that, as we had always suspected, Gary is the chillest and smartest (for proof, click here and read his Hobie Science blogs) person we know. Go check him out shaping live at the Hobie Surf shop in Dana Point, he is usually there in the mornings during the week. Oh, and while you are there, order a handcrafted board from him!

-Tracey Engelking

Hobie Science: Why is the Sky Red?

Red sky night, sailors delight… There may be some truth to this, but why does the sky appear red at dawn and dusk?

From last week’s blog it is understood that sunlight is the visible part of the electromagnetic spectrum and the sky is blue because the high energy blue wavelengths are being scattered and reflected while passing through our atmosphere.

What is happening during sunrise and sunset is that sunlight is passing through a much longer portion of the Earth’s atmosphere.

As can be seen in the image above, lightwaves from the sun are interacting with the atmosphere in a much more tangential manner. This means that lightwaves are not directly hitting the Earth’s surface, rather, they are passing through the atmosphere overhead more parallel to the Earth’s surface. It is only then we can see the red lightwaves being scattered in the sky.

The Earth’s lower atmosphere is much more dense than the air in the upper atmosphere. It is in the lower, dense portion of the atmosphere where most of the aerosols are found. Our atmosphere is mostly made-up of nitrogen and oxygen molecules. There are many other gases, e.g. argon, carbon dioxide, helium, neon, and methane, that vary in quantity depending on location. Many industrial cities have large quantities of manmade aerosols that hover in the lower atmosphere, often gaseous pollutants emitted from all sorts of factories. These areas often have brilliant, deep-red sunrises and sunsets as the lightwaves interact with particulate matter in the air. For us living in Southern California we are familiar with the amazing sunsets during fire season as forest fires pollute the sky with huge volumes of carbon (soot). Coastal cities are also well known for having beautiful sunsets, not due to pollution but because of the amount of salt that is in the lower atmosphere.

So the next time you catch an awe-inspiring sunset, enjoy! And revel in the fact that you now know why you’re seeing red.

-Gary Larson

Hobie Science: Surf Science 101: Why is the Sky Blue?

For this weeks science blog we will leave the oceans and look at what makes the sky appear blue. And no, it is not because the ocean is reflecting the color of the water into the sky. (Ed Note: Full disclosure, I have always thought this to be true before Gary explained it to me)

In order to understand what makes the sky blue we must first understand the basics of sunlight and color. I recently read a fascinating article about a young Isaac Newton’s early experiments with light waves. The year was 1665 and a 23 year-old Newton was home from school due to the plague. Newton confined himself to his room and began experimenting with a prism. He closed his blinds and cut a small hole allowing a small stream of light to pass through. Newton then held a prism into the beam of light causing the light to scatter, ultimately casting a rainbow upon his wall.

“Spectrum of Time” by Peter Erskine

Hobie Surf: Surf Science 101: Reading Buoy Data

For this week’s science blog, I thought it would be useful to take what we have learned in the past two blogs, about wave height and period, and apply that to how we read buoy observations, in-turn allowing us to do our own wave forecasting. Realtime buoy data is abundantly available via the internet through many sites. I find that the National Data Buoy Center (NDBC) online database offers the most helpful wave-data sets. Their database can be found at;  The National Data Buoy Center.

When you are at the NDBC site you will want to choose relevant buoy data that correlates to the location of the beach you plan on surfing at. I will be looking at the Dana Point buoy (#46223) for the following examples because this buoy is close in proximity to my local beaches and it is well exposed to swell from all directions. Some hints when choosing a buoy to use for forecasting; make sure it is not located on the leeward side of an island or tucked in too close to shore where points along the coastline might block swell from the buoy.

The Dana Point buoy collects wave and temperature data and records them every ten minutes.

Hobie Surf: Surf Science 101: Wave Speed

Last week’s blog focused on the genesis of ocean waves. This weeks I will attempt to breakdown the often lengthy journey open ocean waves take on before reaching the coastline. We know that from low-pressure storm activity, strong winds can create waves that can exceed 50-feet in height. Waves of these immense heights are common within the fetch and just outside the area of storm activity but decay rapidly during the initial distance traveled. kind of like how a brand-new car driven off the car lot instantly loses value, waves generally lose between 80 – 90 per cent of their energy in the first 100 miles traveled away from the area of storm activity. So, an initial wave height of 30-feet will be reduced to 6-feet, soon after traveling away from the area of propagation.

Once waves travel out of the fetch, or area where the wind is the generating force, they are no longer wind waves and in-turn identified as free waves, or what we understand as ground swell.

Wave Speed

For me, the most intriguing characteristic of waves is wave speed. As waves travel away from the storm’s influence they begin to organize into groups of waves with similar period and wave length called wave trains or wave groups.

Hobie Surf: Surf Science 101: Genesis of Waves

Welcome to a new feature on our blog, think of it as your Sunday morning read. A chance to get up, sip your coffee and learn something new, or enrich your knowledge on something you already know a lot about. Gary Larson, will take you through the science behind the things we all enjoy, but aren’t really sure exactly why/how they happen in his course  Surf Science 101. Enjoy!!

Waves

Ladies and gentleman summer is upon us and that means south-swells are aplenty. You’re excited for the 18-20 second, New Zealand ground-swell from about 200° but not exactly sure why? Well, feel free to saddle-up for the inaugural weekly installment of Surf Science 101, where I will attempt to enlighten you on some of the perplexing phenomenon we, as surfers, often encounter in the ocean. This week I will be exploring the formation of ocean waves, the variables involved and how they can travel for thousands of miles before breaking along the coastline.

Contrary to the explanations I have heard, from middle America folk to the well seasoned Southern California surfer, waves that we surf on a daily basis are not caused by the moon, tides or the large freighters criss-crossing the ocean. The only variable that is absolutely essential for wave propagation is wind. That’s it. If the planet Earth ditched its moon, ceased all tidal fluctuations and sank every boat in all seven-seas, but wind still blew over the surface of the ocean, we would still have waves.

That being said, there are three important factors that govern wave heights; wind speed, wind duration and fetch. Fetch is understood as the distance over water that wind blows in approximately the same direction. If there is an increase or decrease in any of these three variables the wave height will either increase or decrease, respectively. For example, if a 40-knot wind blew for 24 hours over a 100 mile fetch the wave heights would be larger than if the wind speed was 30-knots and the fetch was 50 miles.

Wave Propagation Chart. Wave heights increase when the wind speed and/or fetch length increases.