Buoyancy: Swim Bladders

Internal_organs_of_a_fishWe’ve all heard that a shark must swim continuously or sink. Do you know why? It’s because sharks do not have a swim bladder. “This gas-filled sac provides buoyancy and helps to keep the fish afloat by keeping it in a neutrally buoyant state.” When in this state, the fish is neither rising nor sinking in the water.

Many bony fish – those having skeletons of bone rather than cartilage like our shark friends – have a swim bladder. It is located in the dorsal portion of the fish as noted in the anatomical sketch included in this post. The swim bladder can expand or contract by filling with or emptying itself of gas through the use of the gas gland. (In some less developed types of fish, the fish fills or empties the swim bladder with gulps of air.) The gas never passes through the wall of the swim bladder. You can think of the swim bladder  as a sort of internal helium balloon.

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Flash Floods and Lyons Colorado

 Lyons, Colorado – in Boulder County Colorado – was the site of horrific flooding over the past few days. The flooding was not just due to rising water levels in rivers and other bodies of water. The flooding was also due to flash flooding that resulted from the huge amount of rain that fell in a very short time.

Lyons, home to “2,000 really attractive and accomplished people,” according to their Visitors Guide. Also according to their Visitors Guide, Lyons is located in the foothills of the Rocky Mountains and surrounded by sandstone ridges that reach to 6,500 feet. This small town also happens to be at the intersection of two canyons. The photos in the Visitors Guide and on the town Web site show a place that is breathtaking – in stark contrast to the images we’re seeing in the news.

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TED Talks

about_tedTED Talks are a way to share Ideas Worth Sharing. It all started in 1984 as a one-time conference to bring people from the technology, entertainment, and design sectors together. Since then, the TED nonprofit has evolved into an organization with two annual conferences, a site to host the videos, and a number of related activities.

TED Talks must be 18 minutes or less. The speakers are invited to make their presentations because they are considered to be fascinating thinkers. There are more than 1,500 TED talks now available for viewing. All of the talks can be viewed for free, and more are added each week.

It’s hard not to be excited at the thought of thought-provoking presentations by respected thinkers. Because of that, TED Talks are a part of this blog. I hope you enjoy them and are intrigued by the ideas they present.

-Gina

Baseball Science

Baseball is all about fluid dynamics – actually aerodynamics – since the fluid is air.

Aerios: concerning the air.Dynamics: force.The Ancient Greeks coined the term Baseballaerodynamics for their study of forces and the resulting motion of objects through air. Today, all the attention a pitcher pays to the placement of his fingers in relation to the seams is done to take advantage of the aerodynamic properties of a ball in flight. Because the seams are the only raised portion of the ball, a baseball made to spin as it moves alternates its smooth and raised surfaces. The cowhide – cut in two peanut-shapes – is smooth.The 216 stitches used to hold the cowhide together, a raised saddle pattern, or double horseshoes, on the ball. These smooth and raised surfaces are the cause of the ball’s performance as it responds to the effects of Lift, Thrust, Drag, and Gravity. Continue reading

August Hiatus

Time for a bit of summer fun!

Meet you back here in September.

Wright Brothers 1901 Glider

The Wright brothers were off and running with their ideas for manned flight. The camber of their wing matched that of the wings used by Lilienthal. Unfortunately, Lilienthal’s figures were incorrect due to an error in the Smeaton coefficient. To get around this, the Wright’s came up with a way to modify the curvature of the wing.

The poor results from these tests led the brothers to undertake wind tunnel tests of their own.

Read more about the Wright Brothers in Modeling Ships and Space Craft: The Science and Art of Mastering the Oceans and Sky by Gina Hagler — Part III – Scale Model Testing Begins, Chapter Nine – The Wright Brothers

Wright Brothers Wing Warping Test 1899

The Wright brothers were able to control the flight of their manned aircraft through the use of wing warping. Far more sophisticated than Lilienthal’s use of shifting body weight, wing warping allowed aerodynamic control of the wing.

The Wright brothers were meticulous in their research. This research, along with their can-do and innovative approach to flight, resulted in their first successful, controlled, heavier than air flight at Kitty Hawk.

Read more about the Wright Brothers in Modeling Ships and Space Craft: The Science and Art of Mastering the Oceans and Sky by Gina Hagler — Part III – Scale Model Testing Begins, Chapter Nine – The Wright Brothers

Wright Brothers 1903 Engine and Propellers

Read more about the Wright Brothers in Modeling Ships and Space Craft: The Science and Art of Mastering the Oceans and Sky by Gina Hagler — Part III – Scale Model Testing Begins, Chapter Nine – The Wright Brothers

Wright Brother Wind Tunnel Testing 1901

This video tells the story of the Wright Brother wind tunnel. As we’ll see later, this had to do with Lilienthal’s experiments and the Smeaton coefficient. For now, enjoy this video. The concepts will be important to us in a bit.

The development of their own wind tunnel and testing apparatus transformed the Wright brothers from tinkering innovators to the first aviation engineers!

Read more about the Wright Brothers in Modeling Ships and Space Craft: The Science and Art of Mastering the Oceans and Sky by Gina Hagler — Part III – Scale Model Testing Begins, Chapter Nine – The Wright Brothers

What is a Coefficient?


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