Technology in the Classroom

December 12, 2011 at 1:52 am

Technological breakthroughs happen every day, and with them come hundreds of new gadgets. In the past decade alone we have taken much that was previously science fiction and turned it into reality. These new technologies have transformed seemingly every part of out lives. However, teachers and professors have for the most part ignored this transformation. The technologies most teachers fully rely on have been around for at lease the past hundred years. They include chalk, chalkboards, and if you’re lucky worksheets. It’s no wonder that so many students have such a hard time focusing in their classrooms. Why would a student pay attention to a lecture they haven’t been following if they can get just as much work done playing Angry Birds? As the world becomes more interesting, instructors need to make their classrooms more accessible and exiting for their student. So, is bringing technology into the classroom the answer? In short yes, technology in the classroom will allow students to become more engaged in what their learning, and bring what they are learning closer to the world they live in.

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One of the top website that students visit is youtube.com. Whether it is to look at funny videos, or to learn how to solve differential equations; it seams that youtube has it all. Videos often contain elements of entertainment that teachers would have a very hard time coming up with by themselves. Videos take you to new locations and show you perspectives that cannot be described. They inspire creativity and fascination in students. Not tomention they keep students more focused. Integrating one or two videos into a slideshow significantly increases the interest of the student in the class, and the impact that the slideshow will have. A video provides information visually, which helps many students who do not learn effectively through note taking alone. A video should not stand-alone. This mean that the teacher must build up to it, and then explain its significance. A video that has nothing to do with the subject is likely to hurt ones cause rather than help it. Youtube videos are easy to access, and cover practically all fields. If teachers want to keep their students attentions then videos are a great tool for them.

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Another great tool teachers can use is Skype. It is a service that allows anyone with an Internet connection and a camera to video conference with anyone anywhere one earth. Using this tool, teachers can talk to their classes without having to be in the same room as their students. The only issue with this is that the teacher cannot actively engage the students. A better use for tools like Skype is to bring lecturers into the classroom. This allows students to meet experts without brining any inconvenience to either party. It’s also much cheaper than having the actual speaker come in. Skype is a great way to engage the students in the lessons. By hearing from real world experts they see how their studies apply to real life.

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The final technological tool I am going to discuss is interactive online activities. Students already spend so much of their time online; it is only natural that homework’s and assignments be transferred to a digital format. Doing problem sets and reading articles is relatively boring, but if these are transferred to an online medium it feels as though there is more freedom in doing them. Online, you can look up things that confuse you while you work through your assignment. This makes homework a much less grueling activity. With activities like this blog students really feel like they are contributing to their own education. By having tests and homework’s online teachers free the students to do their work on their own time instead of using classroom time for something that does not involve the teacher. Online assignments are more engaging, and are typically more fun than print ones.

Technology is what drives the world, and if education does not keep up then many very bright students will be left behind. Digital tools like youtube can bring entertainment and learning to students who have a hard time focusing otherwise. Skype is a way for students to connect to speakers they would never be able to meet in real life. By having assignments that are web-based teachers make the information they teach more accessible to their students. Many teachers still have not embraced technology, but technology is not going away. Those teachers will find themselves in situations where their students are falling asleep in their classes and missing lectures all together. The teachers who have already integrated technology into their classrooms will have a significant advantage in the future. They will have already figured out all the bugs, and all the best resources, while the others are catching up. In Bio Aerial Locomotives we have used all of these technologies and they have helped all of us learn. Although we sometimes ran into problems, that is all part of the learning experience. By encountering these issues now, we can avoid them in the future. Pretty soon classrooms like ours will be examples for how to use technology in the classroom effectively. As technology improves so must educations ability to utilize with it.

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Youtube picture

Skype

Integrating Technology In the Classroom

Effects of Technology on Classrooms and Students

By Ted Sirota | Posted in student post | Tagged , , , | Comments (1)

The kestrel’s wind-hover

December 11, 2011 at 11:25 pm

The kestrel is a spectacular bird, known for its tendency to hunt by flying into the wind at windspeed, resulting in a unique kind of hovering called "wind-hovering". While it is not a true hover, which is achievable only by insects and hummingbirds, it is an effective hover with respect to the ground, and gives the bird an edge in finding prey in flight.

The American kestrel. More colorful than the common kestrel

The American kestrel. More colorful than the common kestrel. Photo (c) J. B. Churchill

Wind-hovering while hunting has been shown to be extremely effective, resulting in 2.82 prey caught an hour, as opposed to 0.21 when perching, 0.31 when soaring, and a measly 0.07 when sitting. The kestrel wind-hovers in bouts of about 25 seconds, after which it either strikes against its prey or breaks the wind-hover and finds a new position to hunt, where it reestablishes a wind-hover. During its lack of motion relative to the ground, the kestrel looks downward and keeps its head remarkably still. This is imperative to the kestrel's hunting, as any movement of the head disrupts its vision and makes it unable to see its targets.The importance of the stability of the kestrel's head results in a new element being required in its flight: intermittent bursts of gliding and flapping.

Ideally, a method of hunting should require a minimum amount of energy and yield a maximum amount of food. Hunting while wind-hovering has already been shown to have a very high food yield, but gliding , which would be ideal in terms of its requirement of energy, results in a downward velocity of the bird, disrupting the glide and the stability of the kestrel's head. With its astounding neck flexibility, the kestrel is able to glide and keep its head fixed while allowing its center of gravity to sink for a short amount of time, but the bird will eventually no longer be able to stretch and its vision will be disrupted, compromising its hunt. Constant flapping flight would solve this problem, but it requires a great deal of energy, making it an impractical method of hunting. The kestrel therefore finds a happy medium: intermittent bouts of gliding and flapping.

Hunting behavior of kestrel.

Hunting behavior of kestrel.

The kestrel enters a glide as it begins its wind-hovering hunt. It then maintains this glide for as long as its neck flexibility will allow without its head stability being disrupted, about 25 seconds. It is then required to flap several times, returning its center of gravity to its initial position close to its head. The kestrel does not always immediately reestablish a wind-hover, but sometimes strikes against its prey at the end of the 25 second period. This may explain why the kestrel wind-hovers in 25 second bursts.

Kestrels are some of the most successful birds of prey, occupying all parts of the world with the exception of Antarctica, the tundras, and deserts. Their remarkable manipulation of the elements to aid their survival no doubt contributes to their resounding success.

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By Solange | Posted in student post | Tagged , , | Comments (1)

The Limit of Aerial Evolution

December 11, 2011 at 7:20 pm

The thought of a Cessna 152 dropping out of the sky from 20,000 ft at 300 mph and pulling out of the plunge five feet off of the ground would scare most pilots to death. But for Argentavis magnificens, it was a lifestyle. Six million years ago, the twenty-three foot wide monster bird would come streaking out of the Andes en route to breakfast, lunch, and dinner.

Argentavis magnificens

Argentavis magnificens was the largest bird to take to the skies in Earth’s history before it died out, but it probably couldn’t fly on its own. Argentavis most likely was a soaring bird, taking wing over the uplift from the trade winds hitting the Andes mountains. While hunting over the papas of modern-day Argentina, the bird would have been entirely dependent on thermals for positive lift. With a takeoff mass of 154 lbs, it would have had to have flight muscles more than 200% larger than is estimated that it actually had based on fossil evidence.

Bone structure

Campbell et al assume that it had to have at least a running start plus a headwind to get off the ground—something that might not have been hard to come by. The trade winds coming in off the coast are very predictable, and the mountainous terrain that Argentavis would have called home would provide plenty of cliffs and slopes needed to get airborne. They calculate that with a 10 degree slope and an 11 mph headwind generated by running, the bird would have been able to get in the air.

Landing would be a whole separate question. Birds of this size would have had to be very careful not to damage a foot or wing when landing/crashing in a controlled manner. Because it couldn’t support its weight by flapping, landing an Argentavis would have been akin to landing a Space Shuttle without computers. The bird would essentially get one shot to come in at a shallow enough glide angle that it could pitch up to stall its wings, bleed off its forward velocity, and plop onto the ground.

While scientists are sure that Argentavis flew because of it's bone densities and muscle cavities, they’re not sure how it hunted. It could have dive-bombed prey on the ground spotted from high altitude. However, Argentavis had one major flaw. Because it couldn’t climb by flapping its wings, it had to maintain enough momentum to climb out of the dive and make the next thermal. If it doesn't make it, it crashes into the ground where it might not be able to take off again anytime soon. Considering that the Peregrine Falcon can reach velocities in excess of 240 mph while in a dive, it’s incredible what Argentavis might have been capable of.

Scale comparison of Argentavis

Using the lift equation and assuming that the wingspan of the bird was 23 ft with a chord length of 4.5 feet, Argentavis was capable of cruising at a velocity of 150 mph in level flight. By comparison, the Peregrine Falcon has a cruising velocity of less than 60 mph. Undoubtedly, the falcon would be proportionally faster in a dive thanks to its exceptional aerodynamics, but velocities in excess of 300 mph for Argentavis are entirely possible.

The talon-eye coordination for these magnificent birds must have been incredible to observe as they would grab a meal from thousands of feet in the air at hundreds of miles per hour with zero margin for error. While aerodynamically they had enough maneuverability to do this, they were more likely to have scavenged for meals like the Condor of today does. It's impressive size would have meant that it could consume most of a dead animal in one sitting, spacing out the amount of times that it would have to eat in a given week or month.

Truly evolution has produced incredible creatures capable of incredible feats. However ultimately, the lifestyle that this bird lived was too demanding of it. Perhaps it simply wasn’t sustainable, perhaps the wind currents that defined it’s habitat shifted, or perhaps the birds simply evolved into smaller species. Regardless, Argentavis demands respect as the greatest bird ever to take to the skies of Earth.

Sources:

  • Chatterjee, Sankar, R. Jack Templin, and Kenneth Campbell. "The Aerodynamics of Argentavis, the World’s Largest Flying Bird from the Miocene of Argentina." PNAS 104.30 (2007): 12398-2403. Print.
  • Norris, Scott. "Largest Flying Bird Could Barely Get off Ground, Fossils Show."National Geographic News. NatGeo. Web. 10 Dec. 2011.

By David Harris | Posted in student post | Tagged , , , , , | Comments (2)

Honeybees: Control of Flight Speed

December 11, 2011 at 5:42 pm

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Honeybees are interesting creatures. They are social and cooperative insects that work together in a harmonized environment. Honeybees are hardworking creatures, pollinating our flowers and creating honey that humans crave. But how are such small and busy insects able to control their flight while being able to dodge obstacles?

It has been determined that honeybees have a dorsal visual field. For such tiny creatures it allows them to be able to avoid obstacle from above. Although this is a known fact among the scientific community, it has been unclear whether this dorsal visual field allows for them to be able to control their flight speed. Until researchers from the Institut des sciences du mouvment conducted studies over the honeybees and confirmed for the public that it does control their flight speed according to obstacle proximity, whether it is in the horizontal or vertical plane. They use perceived optic flow from overhead to achieve this feat.

honeybee2The picture to the left demonstrates a honeybee adjusting its flight speed in order to navigate its way through a very complex setting.

Scientists were baffled and tried to understand how a bee, such a small and simple creature is able to do such an amazing feat. We understand now that a bee's sensory-motor performance depends on a nervous system that consists of millions of neurons. As the bee flies, the image of the environment gets transferred from the front to the back of its visual field, thus creating an optic flow, which is defined in the article "How Do Honeybees Control Their flight Speed to Avoid Obstacles?", as "the angular speed of the environmental contrasts passing [through] its visual field." Optic flows by definition are strongly dependent on the relationship between speed and distance.

In order to be able to study these creatures, the researchers developed a honeybee flight simulation model, called ALIS. Through ALIS the researches were able to conduct experiments on the bees and observe them in a controlled environment. ALIS is capable of reproducing insect trajectories by utilizing computer-processed visual data. They found a bee's speed to decrease whenever it came close to an obstacle. Thus the researchers concluded that the bee's flight speed changes depending on the proximity of a nearby obstruction.

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The fact that bees can control their flight speed is something quite extraordinary. What may seem simple and an everyday matter for them requires hundreds and thousands of money and research to be able to control our airplanes and rocket's speed. In the article, "the scientists point to the existence of controllers to maintain the optic flows." It triggers a "cruise control" method whenever the animal is flying in a crowded environment and helps maintain the speed and distance.

Our own aerospace sensors do not stand a chance against a bee's ability to control its flight speed by being able to use its dorsal visual field. What humans create a bee can simply do. This research can lead to groundbreaking discovery in being able to assist the aerospace field. It can allow for the development of an aircraft that is sensitive to flight in a closed and confined environment. It is amazing to think how such a small honeybee, which may seem very insignificant to many us, can have such highly advanced maneuvering skills.

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By Adrienne Varela | Posted in student post | Tagged , , , , , , , | Comments (1)

The Unique Abilities of Hummingbirds

December 11, 2011 at 5:36 pm

Hummingbirds display exquisite aerial shows that no other birds can imitate. Their anatomical advantage allows them to maneuver their tiny bodies in such intricate ways, like those of an Olympic gymnast; they are able to fly backwards, belly up, and make swift, agile movements during flight. All these unique motions are results of the hummingbirds ability to hover.

What differentiates hummingbirds from all the other species of birds is their ability to produce lift via up-strokes. In "average" birds, 100% of the lift is resulted solely from the down-stroke. The structure of their wing makes it impossible to create adequate force to overcome gravity from the up-stroke; birds can only flap up and down, arc, and fold their wings. Thus, the main objective of the recovery stroke is to create the least amount of drag and negative thrust that will counteract the lift being produced.
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On the other hand, hummingbirds distribute their generation of lift between the down-stroke and up-stroke. The down-stroke supports 75% of the weight, leaving the remaining 25% to be compensated by the up-stroke. Their wings are capable of twisting, creating a beneficial angle of attack in both directions. Even though the up-stroke isn't as efficient as the down-stroke, the constant generation of lift allows them to precisely hover in any part of the atmosphere. The quality of lift during up-strokes can be over looked because of the hummingbird's rapid flapping. They are able to go through 500 wing beat cycles in one second! The combination of twisting wings and unbelievable flapping speed allows the hummingbirds to execute precise and unconstrained movements.

Hummingbirds are also unique in the way they use their tail. In addition to using them as a steering and speed controlling mechanism, they are used for mating. Male species perform high speed dives, reaching up to 50mph. As the male hummingbirds descend, they naturally create a "song", differing depending on the specie. The signature sound produced is altered by the position and shape of tail feathers. Ultimately, it is the vibration, caused by the feathers cutting through the wind, that initiates the beautiful song male hummingbirds sing for their mate.

It is truly amazing how such a small creature can be so phenomenal.

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Sources
- Hummingbirds
- Slow Motion Flight
- Making Songs With Tail Feathers
- Hummingbird Flight
- Hummingbird Documentary

Pictures
- Photo 1
- GIF
- Photo 2

By Brian Nam | Posted in student post | Tagged , , , | Comments (3)