Sandy and Nilam. Those depressing visitors!

Hurricane Sandy began receding on October 31 2012 from the Eastern seaboard of the United States, and cyclone Nilam hit the Eastern seaboard of India on November 1 2012. Both are examples of naturally recurring phenomena that create havoc and cause losses worth billions of dollars, and hundreds of lives every year. The affected areas are still limping back to normalcy.

Cyclones ("hurricanes" in North America and "typhoons" in Japan) are giant storms that have high winds and heavy rainfall produced by a circling vortex of clouds that can be over a thousand miles across. Cyclones are caused by weather depressions. But they are also the cause of fiscal and mental depression because of the damage and chaos they cause.

You can better understand low pressure or depression by understanding pressure itself. 

The Earth is wrapped in a 75-mile-thick film of air; to scale, that is like the film of water on a wet basketball. Towering over any point on the Earth's surface is a column of air approximately 75 miles high. This column of air, with help from the Earth's gravitational pull, exerts a force. Force measured per unit area is called "pressure", and the air we breathe exerts a measurable atmospheric pressure on everything around us, at all times. 

The air is not equally dense at all altitudes - 75% of the air is available closest to the Earth, a zone going all around that is less than 11 miles high. This is the air made up mainly of Nitrogen and Oxygen that all creatures breathe. As you go higher, the density of air reduces as there are fewer and fewer molecules of air available, and it gets more and more difficult to breathe. On the surface of the Earth, this pressure - commonly known as atmospheric pressure and measuring 1 bar or 101,315 Pascals - is equivalent to a standing column of 76 cm of Mercury. In other words, the pressure exerted by 75 miles of atmospheric air equals the pressure exerted by 76 cm of the much denser fluid, Mercury.

An atmospheric depression, therefore, is a low pressure zone within the Earth's atmosphere. It is caused because differing sunshine from the tropics to the poles causes differing ocean temperatures and air temperatures, which in turn causes low and high pressure regions. The characteristic of a low pressure region is that air from surrounding areas rushes in to equalize the pressure. Put very simply, air rushing in to fill an atomospheric depression is what produces high winds, that sometimes go on to create a hurricane; the spinning, moving vortex is formed because the zone of depression itself keeps moving due to the rotation of the Earth.

The greater the difference in ocean temperature, the greater the depression, the greater the velocity of winds, and the greater the storms that are produced. Ever since the invention of barometers, it has been noticed that a drop in air pressure could mean the onset of a storm. Climate change in recent decades has meant higher and higher temperatures, which produce deeper depressions and bigger, more destructive storms.

Keep in mind that 1 bar, or 1000 millibar, is the normal atmospheric pressure at sea level. The atmospheric pressure at landfall of hurricane Sandy (940 millibar) was lower than the pressure of cyclone Nilam (990 millibar). The apparently small difference in pressure, however creates a much magnified effect at the scale of a storm - Sandy had winds as high as 110 mph compared to the 50 mph winds of cyclone Nilam. You can track global temperatures, see how they affect barometric pressures, and understand how depressions form and produce storm systems.

Fearless Felix's free fall, and a discussion of terminal velocity.

14 October 2012: In a much-televised event Felix Baumgartner jumped off a pod floating 39 km (24 miles, or 128,000 feet) over the Earth's surface and straight into the history books.

In one fell swoop, he set the record for the highest jump and the highest speed ever achieved by a non-powered human being in air - 1.24 Mach. Yes, quite astoundingly, he reached a speed of 1,342 kilometers per hour (834 mph), which is 1.24 times faster than the speed of sound. Despite his preparation and the modern technology available to him, an earlier jump by his mentor Joseph Kittinger remains the record for the longest free fall (4 minutes, 36 seconds!)

Felix Baumgartner at work:


Kittinger's free fall record, set way back in 1960,  reached a speed of 988 kilometers per hour (614 mph). While Kittinger's is truly remarkable for being an outrageously bold pioneering attempt, Baumgartner's is special for breaking the sound barrier.

A force "F" that moves a body of mass "m" through a fluid, does so with a resultant acceleration "a", since F = ma. Acceleration causes velocity to steadily increase. Since any real fluid is not without resistance, movement happens at the cost of the body overcoming the fluid's resistance. Eventually, there is a point at which the motive force equals fluid resistance. At this point, the resultant force on the body is zero, which means its acceleration goes to zero, and it cannot go faster than the velocity it has achieved, the so-called "terminal velocity". Any body freely falling through the Earth's atmosphere accelerates at the rate of 9.8 m/s, gradually increases its speed until air resistance nullifies the acceleration.

These achievements, entirely credit-worthy though they are, can create a small doubt in the minds of science aficionados in the matter of terminal velocity: How did these gentlemen manage to exceed the terminal velocity, which is known to be 195 kilometers per hour (122 mph or 54 m/s)?

The answer, my friend is blowing in the wind; terminal velocity is a function of air resistance, and that presupposes the existence of air. Most of the air molecules in the Earth's atmosphere exist below an altitude of 5.5 km. The altitude from which this jump was executed is seriously lacking in air molecules, and therefore lacking in air resistance. Without air resistance, there is theoretically no upper limit to the velocity achievable by a body under acceleration, and that is how Felix Baumgartner was easily able to surpass the terminal velocity as well as the sound barrier.

Assuming that for most of the fall Felix Baumgartner encountered only negligible air resistance, the distance he would have fallen to reach the speed of sound (with initial velocity u = 0, final velocity v = 340 m/s and acceleration = 9.8 m/s):

d = (v² - u²)/2g = 340²/2x9.8 = 115600/2x9.8 = 5898 m or 5.8 km

Also, distance in terms of time taken "t" and acceleration "g", where initial velocity is zero, is:
d = gt²/2

Therefore, the time taken to reach this velocity would have been:
t = sqrt(2d/g) = sqrt(2 x 5898/9.8) = 34.69 seconds.

Comparing the zero-air-resistance calculations to the facts of his free fall (39 km in about 260 seconds), you get an idea of what a great deterrent air resistance is - even when much reduced.

Sports Science: The Unpredictable Knuckleball

What do all sports have in common? Activities as diverse as baseball, basketball, cricket, swimming, gymnastics, snooker/billiards, carrom (or carroms) and cycling all involve an application of one or more principles of science. Sports, with its preoccupation with balance, trajectory, speed, timing and spin, is nothing but a living and breathing science laboratory.

What better way of starting a sports segment on the Exploriments blog than with the national US pastime - baseball? Baseball is so fascinating because it is a duel between the batter's skills and the pitcher's skills. While pitchers frequently employ the fastball, it is the knuckleball that is a more interesting Physics study.

The main skill in throwing a knuckleball, other than being able to dig your fingernails in to hold the ball, is to not impart any spin to it. A good knuckleball turns only a few times during its entire flight. The fact that it has no spin leaves it susceptible to wind eddies and the vortices that form over its seam, and this makes it float in unpredictable ways. 

A regular fastball spins fast about its own axis, giving it the angular momentum and rotational inertia which helps it resist changes to its position. This gyroscopic effect helps the ball retain its orientation and course, making it more predictable to follow around and to catch or hit. A knuckleball neither has the spin, nor the gyroscopic effect associated with spin, making the trajectory of the ball difficult to pick out. This video from Reuters TV shows this Physics principle in action:

The Best iPad apps for STEM and Science Education

Exploriments on iPad are a marriage made in iTunes heaven. They are a boon for all STEM (Science, Technology, Engineering, Mathematics) initiatives and a way to kindle an interest in learning.

Why Exploriments?
Exploriments are apps that use a visual, simulation-based model that invites interaction in the form of touching, tapping and flicking. This game-like feel creates involvement and hikes the fun factor.

Why Visual Simulation?
A computer application (or, Apple app) is more engaging when it is interactive, dynamic, and intuitive. As human beings with opposable thumbs and articulate fingers, we have all evolved standard gestures from interacting with the analog (or real) world. Here are some gestures we use to communicate or realize intention in the real world:

• Jab or point fingers to indicate something
• Turn pages by flicking or swiping
• Move objects on a smooth surface by tapping to grab, dragging and releasing.
• Stretch a flexible surface to increase its size, by parting our fingers
• Roll a cylinder, or show traffic flow by "scrolling" our fingers 

The Language of iPad
Anyone who has used an iPad and has been impressed with its ability to understand what you want it to do, can map each of the gestures mentioned above to an iPad gesture. By making the iPad support universal, non-verbal "intention gestures" on its user interface, Apple has taken our ability to convey intention to a machine to a new level. We know that the iPad is strongly identified with these types of gestures.

iPad and Exploriments - Coming Together
Simulations are computer programs that display objects which need to be moved, dropped, tilted, pulled, pushed, turned ON or turned OFF, in order to interact with other objects, or with the context (environment) itself. Exploriments provides the underlying scientific model (i.e., the rules) of how the objects are allowed to interact - however, it starts when the user first initiates an interaction, which further causes an object to change its state, position or energy level.

Exploriments help you explore Pendulums, Weight and Mass, Simple Circuits, and many more interesting concepts by using game-like simulation and interactivity. This is the ideal toolkit for making learning a fun activity.

Test drive the free Weight & Mass app listed here: http://www.exploriments.com/ipad/Force.html. Bookmark the microsite and visit regularly - we keep expanding it as we add apps.

Happy Learning!

Exploriments are ideal for 1:1 Ipad Initiative schools interested in emphasizing group learning with teacher-led demos and for injecting interactivity into science sessions - available both on the web at  www.exploriments.com OR as iPad apps on the Apple iTunes Store - search by keyword "Exploriments" to see all our apps.

Exploriments on iPad: Episode III

[Previously, in "Exploriments..."

Episode I spoke about how seductive alternatives are drawing people away from education.
Episode II talked about how Simulation can be our Knight in Shining Armor.]

This episode completes the Trilogy by talking about how simulation as used by Exploriments is most effective when it joins forces with the awesomely cool iPad, and emerges as the teacher's ultimate ally in the war on science illiteracy.

An application generates more engagement when it is interactive, dynamic, and intuitive. As humans with opposable thumbs and articulate fingers, we have all evolved standard gestures from interacting with the "analog", or real world. The iPad's interface supports all these instinctive gestures, making it the ideal platform for our simulation based, game-like apps.

Visual simulations and iPads use similar languages of interaction. Add to that the Exploriments frameworks (Pendulums, Weight and Mass, Simple Circuits, etc), and what you get is the ideal toolkit for making learning a game-like, fun, and engaging activity.

Exploriments on iPad: Episode II

"Simulation based education, the most effective e-learning strategy"

A "simulation" in the e-learning context is the scientifically correct representation of a real life experiment - such as a pendulum, a chemical reaction, the archimedes principle, friction, levers, circuits and so on. A simulation allows you to move objects around, set things in motion, use a stopwatch, connect wires, measure either voltage or a pendulum's time period, and hundreds more tasks, depending on the specific application - basically, everything you can do in a physical laboratory. 

However, a simulation can take you beyond the physical limitations imposed by a physical lab. In a simulation there are no real risks, costs, or collateral damage, and this means you can easily explore conditions that are not possible to recreate in a laboratory. For example - you can view and control satellite motion, you can change the gravity under which you observe a pendulum, you can easily change the density of a bob or the liquid when exploring Archimedes principle. You can wilfully cause short circuits, cause electrical devices to fail by passing current higher than their safety rating, or increase weight or gravitational force to the point of failure. 

Understanding science by interacting with accurately modeled virtual objects (weights, springs, measuring devices, atoms, molecules, charged particles, etc), in addition to the freedom to test  boundary conditions, are the big wins of our simulation strategy.

Simulation Differentiators:

A simulation is not a "linear" medium such as a textbook or a powerpoint presentation - that is, it does not require you to go from one thing to another, in a particular order. On the contrary, a simulation lets you approach a scenario from different starting points by varying your exploration each time, in order to get a more nuanced understanding. It promotes a more wholistic and multi-perspective understanding of concepts.

A simulation is also great for progressive learning by starting a concept with baby steps, and slowly building up to the full understanding. 

In the hands of an instructor a simulation adapts to the skill level of a student. Because simulations encompass all the relevant science, it is possible to use the same simulation either for simple, intermediate, or advanced insights.

Computer Modelled Reality being what it is, it is possible for a student or teacher to simulate a large number of combinations and scenarios - indeed, it is possible to stumble upon scientifically valid scenarios that even the creators had not thought! This is very different from a static and linear medium which presents a fixed set of problems, or highlights a finite set of explorations.

Finally, a simulation is virtual which means that it resides inside a computer's memory and can be upgraded, enhanced and improved based on both experience and feedback. Being virtual means that it can take you beyond the accepted physical boundaries of an experiment. This opens wonderful possibilities such as increasing learning potential by adding more objects or insights and increasing engagement and collaboration with a set of teachers and students.

Simulations being dynamic and game-like, do wonders for creating engagement. In the hands of a guide, it becomes an effective tool for involving students. Learning by experiencing the thrill of discovery, and by doing all the tasks leading up to it, make this the ideal educational aid in supplementing traditional methods.

Exploriments on iPad: Episode I

"Education at a crossroads"

More and more, school work is being seen as a boring, tedious, zero-fun game. Movies, games and networking sites are vying for students' attention (and winning). Most methods of teaching used in schools are unidirectional and non-interactive, and that does not help; classroom instruction that only uses the book-and-board route leaves many students unable to cope, or struggling with text that does not adapt to individual needs. 

Schools need a supplement to boost engagement and generate interest.

Team Exploriments believes that a human brain thrives on stimulation, and that is the secret to making learning a fun activity. Studying and learning are activities that are losing ground to gaming and networking. The few students who are interested get tagged geeky or nerdy, and that scares others away. This needs to change. We need role models and change agents to drive this change.

Something is not right. Poor grades and dropouts are on the rise. The lessons taught at school will stick in students' minds if they are fun. This will contribute to a happy, successful and rewarding life. Getting students interested in our technological world should be one of the major aims of education; gaining employment and earning a livelihood are secondary outcomes that will follow automatically, if the first principle is satisfied.

While textbooks, standardized tests and classrooms have their own place, they lack the ability to engage and be fun. Students live in a seductive, media-driven world in which educational aids are forced to compete for attention.

Exploriments offers hope. These are fun apps that allow for self paced exploration

Exploriments was designed to counter this situation. Every app is built from the ground up to reflect our core belief - that a student should learn concepts and ideas the fun way - by interacting with a virtual "lab", by advancing at his or her own pace and learning progressively, by discovering concepts (ably guided by our packaged content) and letting the engagement lead the way to discovery. 

Exploriments enable a game-like immersion, and engage students through the use of interactivity.

The world of pendulums, microscopes, magnets, doorbells, CD players, MP3 players, mobile phones, microwave ovens, cars, computers or even rockets, can be the most exciting of all playgrounds. We believe that the interactivity and game-like engagement achieved by Exploriments makes it a much needed supplement for traditional classroom instruction.