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Fundamental flaws in general physics education

31 Comments
Posted October 21st, 2008 in Physics. Tags: , , , , .

After years of serving as a physics teaching assistant at several public American universities, I’ve come to an alarming conclusion: students in today’s general physics courses (i.e. courses that don’t require calculus, intended for non-physicists) aren’t being taught physics. They might be learning how to mechanically calculate answers, but they’re learning very little about the actual scientific process of inquiring about the nature of reality. They aren’t learning how these physical laws were deduced in the first place– which is far more important than the intricate details of those laws. I think this educational deficiency contributes to widespread misconceptions such as the belief that the Earth’s seasons are caused by variations in the distance from the Sun, and the curious notion that toilets flush in opposite directions on different sides of the equator. Instead of teaching students how to crunch through equations and obtain the “correct answer,” physics courses for general education need to place a higher emphasis on other aspects of the scientific method. Namely, students need to be taught how to evaluate a belief for validity using observations and logic.

I’d describe my application of the scientific method like this: sometimes I notice something strange in my environment, or take a fresh look at a ubiquitous phenomenon. My curiosity’s piqued, so I make at least a token attempt to explain the phenomenon. Historically, the most effective way to approach these problems has been to assume that the universe is governed by objective rules and try to guess a rule that explains the phenomenon in question without implying absurdities. In physics, this search for a mechanism generally involves postulating a general principle (for instance, “energy is conserved” or “objects at rest stay at rest”) and considering the consequences of that postulate. The resulting explanation is “scientific” if it makes predictions that can be verified. This is the primary characteristic of “good” science; not only do our models of reality have to be consistent with the facts at hand, they also have to predict new phenomena which can then be checked via experiment.

Do general physics classes in their current form actually teach students to think using this process? I don’t think so, mainly due to the focus of the course material. A typical problem in one of these classes is formulated like this: “Given this verified physical law, predict the behavior of the following system.” As an example, students are often told to assume Newton’s laws of motion and predict the path of a baseball after it’s thrown. This type of exercise tends to leave the student with the impression that science is a mechanical system of picking a set of equations and churning out an answer. Problems like these are certainly good practice for learning how to apply physical laws to obtain specific predictions, but that’s nearly irrelevant for a student who doesn’t intend to become a physicist.

A better approach would actually require the students to construct hypotheses regarding phenomena that seem confusing, and have them test these hypotheses by considering what they imply about the real world. Though we’re probably succeeding at teaching people the mechanics of working within a given scientific theory, it’s more important to show them how those theories were constructed in the first place. Students need to be shown how to take an explanation of a phenomenon and test it for validity.

We’re failing miserably at this goal.

For instance, if college graduates were randomly surveyed regarding the cause of the Earth’s seasons, I think a sizable percentage of them would say that the seasons are caused by variations in the Earth’s distance away from the Sun. This misconception only arises because students aren’t being taught to critically evaluate ideas in terms of their implied effects. Consider this: if winter occurs when the Earth’s farther away from the Sun, doesn’t that idea imply that winter should occur at the same calendar date everywhere on the globe? If seasons really were caused by the Earth’s distance away from the Sun, the seasons would be the same everywhere because the Earth as a whole would be closer or farther from the Sun. This isn’t true, though: in the southern hemisphere, summer occurs in January, and winter occurs in June (vice versa for the northern hemisphere). In other words, if you believe that seasons are caused by distances from the Sun, you’d be likely to pack completely inappropriate clothes for a “summer” plane trip across the equator.

What’s the actual cause of the seasons, though? More importantly, how do you determine that cause? I’ll answer that question with another question: Why do winters get colder as you move farther away from the equator? Is it because the distance to the Sun increases as you approach the planet’s poles?[1] No, not in any significant sense; the Earth’s usually ~150,000,000 kilometers away from the Sun and the Earth’s only ~12,000 kilometers in diameter. So any movement you make on the Earth’s surface is an infinitesimal fraction of the distance to the Sun; it shouldn’t play a role in determining temperature.

However, the Sun is lower in the sky when you’re farther from the equator. This relationship’s easiest to see if you draw a picture of the Earth in its orbit with the axis of rotation of the Earth (roughly) perpendicular to the line that connects the Earth and the Sun. A person standing on the equator will see the Sun pass nearly directly overhead during the course of the day, but a person very far north (or south) of the equator will never see the Sun directly overhead. This means that less light intensity is reaching the Earth’s surface at those points far from the equator- less light per square meter is hitting the ground because it’s not shining directly vertically. Again, the best way to see this is to draw a picture and investigate the geometry of the situation on your own.

How does this explain the seasons, though? The seasons occur because the axis of rotation of the Earth’s actually tilted[2] away from being perpendicular to the line that connects the Sun and the Earth. This axis stays in the exact same orientation (relative to the “fixed stars”) as the Earth orbits the Sun, so sometimes the northern hemisphere’s pointed towards the Sun (this produces a northern summer and southern winter) and sometimes the southern hemisphere’s pointed towards the Sun (which occurs during northern winter and southern summer).[3]

The actual scientific process involved in this explanation is the recognition that a common misconception (seasons being caused by distance changes) predicts incorrect phenomenon (winter and summer occurring at the same time everywhere on the globe). This realization’s followed by a different model for the seasons (the tilt of the axis) and should then be followed by observations that confirm that model. For instance, you could observe the Sun staying lower in the sky during winter than during summer to verify the “axis tilt” model of the seasons.

This brings me to my next pet peeve. In the Simpsons episode “Bart vs. Australia,” the U.S. Embassy in Australia has gotten fed up with the way water drains in the southern hemisphere and installed a special device on the toilet to “make the water drain in the American direction.” I believe this scene’s representative of a widespread belief that water drains counterclockwise in the northern hemisphere and clockwise in the southern hemisphere.

The purported cause of this difference is a real phenomenon called the Coriolis effect. In order to understand the Coriolis effect, consider a person standing on the equator. Because of the rotation of the Earth, he’s actually moving in a large circle at a very high speed.[4] A person sitting exactly on top of the North or South Pole, in contrast, would simply be spinning once every 24 hours- he wouldn’t be going anywhere. At intermediate latitudes the speed varies smoothly from a maximum value at the equator to zero at the poles.

Suppose you stand at the equator and fire a cannonball directly north. In addition to the northward velocity from the cannon, the cannonball has the high velocity of rotation of the equator, and as it flies north it retains that velocity.[5] However, once the cannonball travels a significant distance, the ground underneath it isn’t moving as fast as the cannonball so its path will appear curved relative to the ground. Because the Earth rotates from west to east, the cannonball will appear to be “pushed” to the east by the Coriolis effect. This is the modern explanation for why hurricanes rotate in preferred directions in different hemispheres.

Does this explanation apply to toilet bowls and sinks, though? The cannonball’s path isn’t noticeably curved unless the cannonball travels very far to the north. That’s why hurricanes are affected by the Coriolis effect- they’re large enough so that the eastward deflection is sizable. But toilet bowls and sinks are millions of times smaller- the Coriolis effect’s way too small to have any measurable effect on them. The tiniest imperfection in the shape of a sink’s drain or random circulation of water flowing down it would completely mask any Coriolis-induced spinning.

That’s a physics explanation of why this “rotational drainage” myth isn’t true. I included it for completeness’ sake, but my main point is that physics education shouldn’t be about supplying explanations to students. Science education should teach students how to create and test their own explanations. Let’s say that I did believe that sinks drained in preferred directions. How would I test this belief for accuracy? Well, I’d just have to wash my hands in different sinks and see whether the water drained in a consistent direction in this hemisphere. Try it, and you’ll see that this simply doesn’t occur- water drains clockwise or counterclockwise in different sinks even when you’re far from the equator. Hint: if it’s difficult to see which way the water’s draining, try sprinkling some pepper on the water so you can see the circulation pattern more clearly.

Why do otherwise intelligent people believe in effects that can be disproved just by looking in the sink? I think it’s because no one ever takes the time to emphasize the importance of verifying beliefs through experiment. That’s what science classes should be doing, but instead they’re teaching medical students the arcane intricacies of Newtonian mechanics without even attempting to test whether or not those students understand how Newton discovered his theory in the first place.

It should now be obvious that there’s an inadequacy in our science education system. Why does this inadequacy exist, though? The obvious reason is that a mechanical, computational approach is easier to apply in larger classes, and it easily translates into an objective grading system. This is probably unavoidable in today’s large universities, but part of the problem’s due to the fact that general physics classes are treated as “watered-down” versions of the introductory physics courses that are intended for physics majors. This is convenient for the instructor, of course- the material’s easy to translate from one class to another. It’s inappropriate for the students, though, because the major-based physics courses are simply treated as the first stepping stone to building a scientific mindset. These first courses are where physics majors gain practice at mathematical computations; the real science actually comes into play much later. For general students, however, these few physics courses are the only glimpse of the subject they will ever see. We can’t afford to ignore the more important aspects of the scientific method, even if it means the class structure has to be changed significantly.


Footnotes

  1. I mention this possibility because many students suggest it as a possible reason why winters are colder when you’re farther from the equator. ↩ back
  2. The axis is actually 23.5° away from being perpendicular. ↩ back
  3. Due to the geometry of Earth’s orbit around the Sun, northern winters occur when the Earth is closest to the Sun. ↩ back
  4. A person on the equator is rotating on a circle of radius 6400 km (the radius of the Earth) and they complete one circle a day, so their speed is ~460 meters per second (greater than the speed of sound at standard temperature and pressure!). ↩ back
  5. Ignore air resistance for the purposes of this explanation. The cannonball simply obeys Newton’s First Law: “Objects in motion remain in motion.” ↩ back

(Ed. note: This article was originally written on 2003-08-20.)

Last modified February 6th, 2012
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31 Responses to “Fundamental flaws in general physics education”

  1. Reythia posted on 2008-11-24 at 10:29

    Haha! We had a discussion about this at lunch. Don Chambers initiated it and was about as irked as you seem (and I am, for that matter). We were talking about middle school and high school science, not university level, but the problem exists throughout. I know that, personally, I only had ONE pre-college science teacher who taught science “the right way” — as a system of experiments, rather than a set of laws. As it happens, he DID teach us the correct reason for the seasons — and pointed out what would have happened if the seasons had instead been caused by a change in distance to the sun, too. He was a very good teacher, which none of my others matched up to, though.

    I think that it’s a sad thing to realize that, by the time high school starts, science has become a set of equations and rules and facts to memorize, rather than a class used to gain understanding about the world around us. This is less true in elementary school. There, we plant the bean seeds in the milk carton and learn that plants grow because of the sun because the ones in the closet DIED! This is the scientific method. It’s a shame that (most) middle and science teachers fail to teach it similarly, but at the higher level needed for the age of their students.

    Then again, to be fair, the teachers DO need to teach the math, too. I mean, especially in physics and chemistry, science is defined by mathematical laws. It’s important that high schoolers learn that a wave in a pool of water decreases in amplitude the farther out it goes, and that is best taught via labs. But it’s also important that they understand that the WAY it decreases in amplitude isn’t just random, that it’s defined by a mathematical rule. And while some students (hopefully including those who want to go to college for mathematic, scientific, and engineering-related studies!) will be able to figure out that basic relationship on their own, others are quite simply not so capable. So the teacher is stuck with a choice: teach everyone the mathematical rules explicitly (in which case the “clever” students will not gain the understanding they would have by figuring it out themselves) or let the students learn the truth through carefully guided labs (in which case the “less clever” students will not learn that science is bound by certain mathematical guidlines). Either way you pick, someone’s going to learn less than she could have.

  2. I agree that a class oriented towards hypothesis testing would be more useful for “clever” students. A more “concrete answer based” approach presents phenomena in tangible terms that are probably easier to convey to students who find abstract thought difficult.

    However, there’s a difference between grasping an idea and retaining it. Yes, scientific statements are best expressed using math, and it’s vitally important to teach that math to anyone who actually intends to be a scientist or engineer.

    But non-scientist students aren’t going to do that. The math flies out the window as soon as the class is over. Maybe they’d learn less in a lab dedicated to hypothesis testing, but they might retain more after the class is finished.

    And what they retain will be more useful than a formula. It’ll be an approach to gaining knowledge, rather than the table scraps of someone else’s search for knowledge.

    (In my mind, the most serious stumbling block is how we’d come up with a fair and objective grading system for such a class. How frustratingly subjective it’d be to assign grades!)

  3. Mitchell posted on 2009-09-14 at 16:06

    Fermi questions permit rough quantitative reasoning about the world. K-gray, being quantitative can simplify explanations and aid scientific reasoning. And then, explicitly providing a framework of knowledge about the world allows for broad and rich, understanding and reasoning.

    The choice isn’t math *or* reasoning. It’s how to best combine those, and more.

    Despite being hard, few resources, incentives, communities or institutions are focused on doing that. So long-term miserable failure shouldn’t be a surprise.

  4. Found this helpful archive of Fermi questions. Thanks.

    Perhaps “K-gray” refers to this website?

  5. Reythia posted on 2010-03-15 at 15:01

    Thought you might appreciate this.

  6. That article sums up my feelings on the matter perfectly. Thanks!

  7. Physics without math? Is that really possible? and then objectivism versus subjectivism?

    “Ah, what a tangled web we weave…” when at first our eyes perceive. Enjoy that which can be explained, shrug your shoulders when you can’t. Physics explains what the heart cannot, the heart explains what physics would like to understand.

  8. Dr. Philip Bhang posted on 2015-07-31 at 08:15

    “Suppose you stand at the equator and fire a cannonball directly north. In addition to the northward velocity from the cannon, the cannonball has the high velocity of rotation of the equator, and as it flies north it retains that velocity.[5] However, once the cannonball travels a significant distance, the ground underneath it isn’t moving as fast as the cannonball so its path will appear curved relative to the ground. Because the Earth rotates from west to east, the cannonball will appear to be “pushed” to the east by the Coriolis effect. This is the modern explanation for why hurricanes rotate in preferred directions in different hemispheres.”

    I think you have something wrong here. No offense but I think you made a mistake.

    1. The underlying assumption cannot be demonstrated in experiment. At least not in a lab. So if the explanation is more involved, it would be educational to learn it.

    The direction of cannonball motion horizontally would not be retained as its an illusion. All we’d expect to see is the cannonball flying North with the energy from its firing and being on a spinning globe.

    http://video.mit.edu/watch/the-coriolis-effect-4407/

    at 0.58 or so-
    blue dashed straight line shows the motion of the ball- none of the motion you claim would be retained, is. Newton’s laws are obeyed. The ball simply follows one direction of motion, not two, traveling in the direction it was thrown in.

    MIT students demonstrate the Coriolis Effect. They use a merry go round set up and try to throw a ball back and forth. Its obvious that the effect is due to the thrower and catcher rotating away from the ball after it is thrown. The ball does not retain any of the rotation it had as a result of being thrown from a spinning platform. It simply obeys Newton and flies in a straight line relative to the unmoving lab. Just like ballistic physics expects it to. All laws are obeyed.

    In other words, this last point shows the fallacy in your argument. The additional motion you claim the cannonball has, cannot be demonstrated in experiment. You are simply claiming the cannonball is doing something without showing any empirical evidence to support your assertion. A stone shot from a sling does not retain the rotary motion that empowers its flight. It obeys Newton’s first law. The motion contributes to its energy not its direction. Its energy goes into one direction and one only- the straight line.

    “The centrifugal force is often mistakenly thought to cause a body to fly out of its circular path when it is released; rather, it is the removal of the centripetal force that allows the body to travel in a straight line as required by Newton’s first law. If there were in fact a force acting to force the body out of its circular path, its path, when released would not be the straight tangential course that is always observed. ”

    http://www.infoplease.com/encyclopedia/science/centripetal-force-centrifugal-force.html

    If the walls of a centrifuge were to disappear, the particles of matter within fly off in a straight line. Here there is no string. So why would the cannonball retain this illusionary translational velocity? It has orbital motion, not translational motion, despite the illusion we experience.

    This last point is of major importance as Arthur C. Clarke (among others) makes use of it in order to explain how we can have communication satellites in geostationary orbit. ( in an article from 1945 or so ) Clarke uses the centrifugal equation to show how gravity can be negated. This is predicated upon the difference between an orbit and flying off in a straight line.

    http://www.wired.com/2011/05/0525arthur-c-clarke-proposes-geostationary-satellites/

    Its exactly the motion not being translational and being orbital or rotary, that enables things like artificial satellites and the space program. Without things like escape velocity, and orbits and the illusionary “centrifugal force”, there would be no great leaps of humankind into the outer Universe and we’d be forever trapped on this small blue marble.

    https://en.wikipedia.org/wiki/Escape_velocity

    “If an object attains escape velocity, but is not directed straight away from the planet, then it will follow a curved path. Although this path does not form a closed shape, it is still considered an orbit. Assuming that gravity is the only significant force in the system, this object’s speed at any point in the orbit will be equal to the escape velocity at that point (due to the conservation of energy, its total energy must always be 0, which implies that it always has escape velocity; see the derivation above).”

    As you can read for yourself no curved path = no orbit. An orbiting geostationary satellite has a different translational velocity than its ‘twin’ on the Earth so many miles directly below. It covers more miles since it is further away from the surface or center of the Earth. And yet both stay in the same exact position relative to each other. What you are referring to is simply an illusion of the senses. We cannot perceive the rotundity of our world, not being this close to it. We are not traveling in a translational motion on the Earth surface. Such a thing is impossible on our rotating globe. The motion cannot in any way be truly considered translational as that is completely at odds with reality. It is clearly circular motion.

    A thought experiment:

    Location: Moon surface a constructed highway that circles the Lunar equator.

    A super Tesla electric car capable of incredible speed. No air means no friction.

    The car accelerates until it reaches the proper velocity calculated to cancel the Lunar gravity. As it does so we watch the car rise up into the heavens. If the car was on a fly world this would not be the case. Its the fact that we are on a globe and the motion is actually circular that enables our car to take flight in such a manner. In perfect vacuum its motion is retained forever.

    We know this is all true as we have a bulge at the Equator. Were the motion at the equator as simply as following a straight line, there’d be no bulge. The bulge is a direct result of our rotation about our axis. This also makes us a bit lighter on our feet, as long as we stay away from the poles.

    The satellite and the spot on the ground so many miles below stay in relative position to each other ( leaving aside minor corrections for orbital eccentricities ) despite the MPH translational difference. In reality we are rotating.

    So pointing to a difference in perceived motion is not the same thing as what is happening in reality. We speed around this Universe on our space ship Earth at incredible speeds without noticing it a bit. To say otherwise seems as mad as claiming Einstein wrong or that the world does not move.

    2. We know the atmosphere moves with the rotating and orbiting Earth. For example, no constant 1000 mph wind at equator.

    3. We know gravity keeps the gasses in place on our moving world. Powerful enough to prevent the atmosphere from escaping into the unimaginable vacuum of our solar system and Universe. Also powerful enough to ignore the 66,000 mph velocity of our planet around our star. As well as any and all compounded motion around the Universe.

    Besides lines of longitude move together as one. No lead or lag.
    A position at the same longitude but at the equator moves at some 1000mph west to east. Some distance to the North, AT THE SAME LONGITUDE, the position is moving at say 750 mph. And yet both positions maintain a constant relative distance. Rotation has a different effect on motion than translation does. We are simply so used to perceiving the world as flat we forget we are on a globe.

  9. Dr. Philip Bhang posted on 2015-07-31 at 09:59

    Some further thoughts:

    The lines of longitude move closer together the further away from the Equator one moves.
    Look at a globe. The actual physical sphere actually bends and warps actual physical substance and a term like ‘space’. In this case the land, water and gaseous mass is spherically shaped.

    As a result, the distance between the lines of longitude and latitude change. The lines get closer together the further from the Equator until meeting at mathematical points at the North or South Poles.

    This ‘warping’ of actual physical shape means the cannon’s target at the northern latitude has to move that much less distance to the East than the cannonball does.

    At the Equator the lines of longitude are so many miles part and to the North or South the lines are less miles apart. Gravity keeps the cannonball centered on the globe, so atmosphere and its friction aside, the globe’s shape would compensate for the apparent speed difference between the Equator and the Northern or Southern latitude.

    Compare a cannonball shot from the Equator to a target at 40 degrees North. This cannonball can travel for one hour and in that time travels to the target latitude. Keeping in mind the lines of longitude show the geography getting closer together, we can see how the 69.172 miles difference between the line of longitude at the Equator compensates for the diminished 53 miles between lines of longitude at 40 degrees latitude.

    Some basic mathematics that anyone is capable of will clearly show that the shape of the Earth compensates for the apparent difference in translational velocity from Equator to Poles.

    One hour cannonball flight time-travelling at 2752.37 mph so it hits its target in one hour.

    At 40 degrees North- an imagined point would travel some 794.80665 miles during the hour, due to Earth’s rotation. At the Equator and on the same line of longitude, it travels some 1037.5646 distance. At 40 degrees North, the lines are 53 miles part. At the Equator the lines of longitude are 69.172 miles apart.

    Imaging the Earth to spin while the lines of longitude stay in place. At 40 degrees North, the velocity divided by the number of lines yields 14.99635 lines of longitude the Earth at that latitude would pass over in one hours time it took our cannonball to reach its target. At the equator the number of lines works out to 14.99977. One sees that the difference at some 2752 mile difference is on the terms of thousands of a mile.

    Its not like the cannonball can miss the Earth. Gravity pulls it towards Earth’s center. Or its barycenter, if one wishes to be more specific. In any case the force we call gravity keeps the cannonball from missing the planet. The curvature of the Earth compensates for the apparent velocity difference between the Equator and the Northern target.

    some helpful links:

    http://www.stevemorse.org/nearest/distance.php
    http://geography.about.com/od/learnabouttheearth/a/earthspeed.htm
    http://boatsafe.com/tools/scale.htm

  10. Dr. Philip Bhang posted on 2015-07-31 at 10:03

    Correction to above- distance between longitude changes. Latitude is not altered like longitude.

    “The actual physical sphere actually bends and warps actual physical substance and a term like ‘space’. In this case the land, water and gaseous mass is spherically shaped.”

    Meant to write

    “…and NOT a term like ‘space’.”

  11. Dr. Philip Bhang posted on 2015-07-31 at 10:06

    Northern or Southern latitudes do not have to cover as much distance as a location on the Equator in the same amount of time due to the shape of the globe. So the lesser velocity is compensated by the lesser distance and all in proportion to the difference in degrees between the Equator and the Poles. At the extremes, the Poles do not have any translational motion.

  12. Dr. Philip Bhang posted on 2015-07-31 at 10:09

    The shape of the globe means the Northern target moves the same amount proportionally to the cannon’s position on the equator and the retained motion of the cannonball fired in vacuum.

  13. Dr. Philip Bhang posted on 2015-07-31 at 10:10

    If cannonballs stray, it would seem the cause is something else. like say the tail winds or something like that.

  14. Dr. Philip Bhang posted on 2015-07-31 at 10:43

    From the North 40 degrees firing South to the target on the Equator using the above set up shows us that we should miss our target as our cannonball ends up too far to the West relative to the East moving target.

    The cannonball has an easterly velocity that is less than the target’s eastern velocity and the lines of longitude spread further apart as the latitudes closer to the Equator move faster and faster beneath our cannonball.

  15. The direction of cannonball motion horizontally would not be retained as its an illusion. All we’d expect to see is the cannonball flying North with the energy from its firing and being on a spinning globe.

    Good grief. If you fire a cannon ball north from the equator, it retains its initial eastward velocity. Here are more references confirming this fact.

    It simply obeys Newton and flies in a straight line relative to the unmoving lab. Just like ballistic physics expects it to. All laws are obeyed. In other words, this last point shows the fallacy in your argument. …

    Good grief. There’s no fallacy in my argument. The fact that Newton’s laws are obeyed is exactly why the cannonball retains its initial eastward velocity. It travels in a straight line in an inertial nonrotating coordinate system, but follows a curved path relative to the rotating coordinate system defined by Earth’s rotating surface. That’s completely consistent with that MIT video.

    The additional motion you claim the cannonball has, cannot be demonstrated in experiment. You are simply claiming the cannonball is doing something without showing any empirical evidence to support your assertion. … If cannonballs stray, it would seem the cause is something else. like say the tail winds or something like that.

    Are you sure it can’t be demonstrated in experiment?

    “This effect was largely a curiosity until World War I, when the Germans built a generation of long-range cannons and found that they could not hit anything if they aimed directly at it; they had to aim to the left.”

    The fact that cannon balls retain their initial eastward velocity from Earth’s rotation had already been demonstrated in experiment about a century ago. If this were really due to tail winds, why would the deflection always be in one direction and have the magnitude predicted by Newton’s laws?

  16. Dr. Philip Bhang posted on 2015-07-31 at 13:59

    “The fact that Newton’s laws are obeyed is exactly why the cannonball retains its initial eastward velocity. It travels in a straight line in an inertial nonrotating coordinate system, but follows a curved path relative to the rotating coordinate system defined by Earth’s rotating surface. That’s completely consistent with that MIT video.”

    I posted the video in context of illustrating how the ball lacks the extra motion you claim it would have.
    it only moves in one single direction. Not two. Once it is thrown, the directional vector is chosen and it is no longer in an accelerated rotational frame. Like the sling being swung around prior to letting the stone fly.

    The stone does not retain any motion from the twirling around one does prior to letting the stone fly forth. Once the sling is released a specific direction is chosen and that is that. There is no other directional motion associated with the flying projectile.

    See what I mean?

  17. Dr. Philip Bhang posted on 2015-07-31 at 14:02

    “The fact that cannon balls retain their initial eastward velocity from Earth’s rotation had already been demonstrated in experiment about a century ago. If this were really due to tail winds, why would the deflection always be in one direction and have the magnitude predicted by Newton’s laws?”

    Again- this eastward velocity is not maintained in the MIT video.
    This flies in the face of basic centrifugal experiments.

  18. Dr. Philip Bhang posted on 2015-07-31 at 13:54

    Then of course there’s the notion of gravity and its vector.
    The square distance law illustrates this principle. An object in motion along the Equator, for example, or moving from the Equator and traveling North like our cannonball, is subject to the changing gravity vector and is in a state of acceleration. Since the Earth is round, this acceleration is ‘centrifugal’.

    The cannon on the Equator or anywhere else on Earth, can never be able to somehow retain a translational motion that does not exist in the first place. The fact that the direction of gravity changes as it moves proves this. The motion is rotational and that means once the object is shot forth, it picks a direction and the former motional energy is converted into a force in that direction. Just like a stone from a sling. Basic centrifugal force at work.

    Now if for some reason we want a different model, that’s fine. It just has to be logically consistent.

    Curved space is here exemplified with curved geometry and longitudinal lines that literally meet at points on the globe. As Einstein proposes, space itself might seem straight to us, but it is actually curved around mass, or due to the pretense of mass. Look at a globe and see how it is shaped and how the lines run together at the poles.

    This curvature would automatically adjust the speed of the cannonball so that its velocity was appropriate to its new gravitational vector as that angle constantly changed. Or Einstein is wrong.

    Let’s not forget that if one travels from Equator to Pole, one finds oneself turning 90 degrees. This cannot simply be ignored. As the cannonball travels, its gravity vector changes. Gravity projects out from the Earth radially, along normals. This is the means by which the apparent translational velocity is altered as the projectile travels. Basic curved ‘space’ stuff.

  19. Again, if you fire a cannon ball north from the equator, it retains its initial eastward velocity. Here are more references confirming this fact.

    If you still want to dispute this fact, please talk to them. I’m busy.

  20. Dr. Philip Bhang posted on 2015-07-31 at 14:11

    And that would contradict the MIT experiment.
    So there is something else involved and not the “Coriolis effect”, which is an illusionary force anyway.

  21. Dr. Philip Bhang posted on 2015-07-31 at 14:09

    The fact is the world is a globe and not flat. Einstein based his entire life’s work on the very notion that space itself can be curved round a mass. You are not making sense. The curved lines obviously all close in on two points at either pole. The distance between the lines of longitude change. This is exactly the Gaussian shape of things Einstein is talking about in his work. Gravity simply means curved space. No work has to be done.

    Gravity would have the Earth be a perfect sphere. Were it not for the centrifugal force we’d have just that.
    We know this from satellites and like technology. The apparent pull of gravity is towards center. An object traveling along the globe has by definition changing gravity vector. It is in a state of acceleration. If one fires a cannonball from such an object, one would expect it to act like the ball in the MIT video and not retain the illusionary eastward motion.

    Even on the Earth we can tell we are on a globe, the way the Moon starts off at one angle and ends at another, clearly shows this.

    The experience of a flat Earth is an illusion.

  22. You’ve said your piece. Please leave me alone.

  23. Dr. Philip Bhang posted on 2015-07-31 at 14:17

    Don’t respond to ‘some guy’ on the internets if you don’t like what he has to say.

  24. Dr. Philip Bhang posted on 2015-07-31 at 14:16

    Thanks for the links, but I don’t think they help. I don’t think you see my point. What is being discussed is clearly not something we can simply replicate with a basic merry go round and thrown object. The MIT video shows that. We are discussing something else when we get into cloud structures and the like. Assuming that natural phenomena must only be attributed to an illusionary force is very odd. Especially when the lab experiment shows its faulty.

    We have people in space. We’ve been to the Moon. Sent a probe to Pluto. Etc. There is no need to confuse the public with nonsense. A straight answer would be nice.

    There has to be logical consistency between what can be demonstrated in experiment and what claims are made to explain much larger scale phenomena.

  25. Again, please leave me alone.

  26. Dr. Philip Bhang posted on 2015-07-31 at 14:37

    Sure thing friend.

    But why even respond beyond what you were willing to write in the first place?

    Me, I’d have ignored someone like me. Or wrote something like:

    “Very interesting points, thats something for you to look into…”

    But hey you are the guy who wrote:

    “After years of serving as a physics teaching assistant at several public American universities, I’ve come to an alarming conclusion: students in today’s general physics courses (i.e. courses that don’t require calculus, intended for non-physicists) aren’t being taught physics. They might be learning how to mechanically calculate answers, but they’re learning very little about the actual scientific process of inquiring about the nature of reality.”

  27. Again, please leave me alone.

    Sure thing friend. But why even respond beyond what you were willing to write in the first place?

    Because I foolishly hoped that asking you to “please leave me alone” would cause you to leave me alone. It didn’t work.

    Me, I’d have ignored someone like me. Or wrote something like: “Very interesting points, thats something for you to look into…”

    Is that the only way to get you to leave me alone? I won’t do that, because your comments aren’t “very interesting points”. You’re fundamentally confused about basic physics and baselessly implying that I’m somehow confusing the public with nonsense.

    After dozens of tedious and insulting “conversations” like this one, it’s become clear that they’re completely pointless. For instance, if I explained once again how your claims are wrong, you’d probably just keep repeating them (with minor changes) until I have to give up anyway. The only difference would be the amount of time I wasted.

    Let’s demonstrate my point:

    “The fact that Newton’s laws are obeyed is exactly why the cannonball retains its initial eastward velocity. It travels in a straight line in an inertial nonrotating coordinate system, but follows a curved path relative to the rotating coordinate system defined by Earth’s rotating surface. That’s completely consistent with that MIT video.”

    I posted the video in context of illustrating how the ball lacks the extra motion you claim it would have. it only moves in one single direction. Not two. Once it is thrown, the directional vector is chosen and it is no longer in an accelerated rotational frame. Like the sling being swung around prior to letting the stone fly.

    The stone does not retain any motion from the twirling around one does prior to letting the stone fly forth. Once the sling is released a specific direction is chosen and that is that. There is no other directional motion associated with the flying projectile.

    See what I mean?

    The stone released by a slingshot retains the velocity from twirling around in exactly the same way that a cannonball retains its initial eastward velocity. If cannonballs didn’t retain that initial eastward velocity, stones would simply drop straight to the ground after being released from slingshots without retaining any velocity from twirling around.

    Again- this eastward velocity is not maintained in the MIT video. This flies in the face of basic centrifugal experiments. … that would contradict the MIT experiment.

    If one fires a cannonball from such an object, one would expect it to act like the ball in the MIT video and not retain the illusionary eastward motion.

    Nonsense. The MIT video doesn’t show that objects don’t retain their “eastward motion”. It shows that the throwers are compensating for their “eastward motion” by aiming to the side, just like the Germans did to hit targets at long range.

    Thanks for the links, but I don’t think they help. I don’t think you see my point. What is being discussed is clearly not something we can simply replicate with a basic merry go round and thrown object. The MIT video shows that.

    No, it doesn’t. It shows that they’re not aiming directly at the catcher, because they have to compensate for the fact that the ball retains their “eastward motion”.

    This can be simply replicated with a basic merry go round, but a “thrown object” confuses the issue because the exact angle isn’t replicable or even known to the thrower, because with practice humans subconsciously compensate for the fact that the ball retains their “eastward motion”.

    Instead, consider a water gun taped horizontally to the edge of the merry go round, securely aimed exactly at the merry go round’s center. This fixes the exact angle at which the water (the “thrown object”) is “thrown” in the same way that we’re specifying the cannon to be aimed exactly north.

    When the merry go round is stationary, the water gun will hit the center of the merry go round.

    When the merry go round is spinning, the water gun won’t hit the center of the merry go round because water “thrown” from the water gun retains its “eastward motion”.

    The fact is the world is a globe and not flat. Einstein based his entire life’s work on the very notion that space itself can be curved round a mass. You are not making sense. … Gravity would have the Earth be a perfect sphere. Were it not for the centrifugal force we’d have just that.
    We know this from satellites and like technology. … Even on the Earth we can tell we are on a globe, the way the Moon starts off at one angle and ends at another, clearly shows this. The experience of a flat Earth is an illusion.

    Good grief. Please stop lecturing about how the Earth isn’t flat. As I’ve explained, I process GRACE data using an open-source program that models the Earth as an ellipsoid with parameters taken from NASA satellites.

    Your baseless and insulting implication that I need to be educated about the shape of the Earth is another clue that this conversation will be just as pointless as all the others I linked. What will you lecture me about next? Water is wet?

    Again, please leave me alone. Unless you’d like to demonstrate my point by continuing to repeat your incorrect claims (with minor changes) until I have to give up anyway.

  28. Dr. Philip Bhang posted on 2015-08-02 at 12:36

    As the direction of gravitational pull changes as the object moves around the globe, the circumferential velocity changes accordingly. And thus there can be no Coriolis effect on the rotating Earth.

    The inertia from the Earth’s motion(s) is potential and as long as the object is subject to the inertia and gravity of the Earth, that potential stays as potential and is not actualized until escape velocity is achieved, if ever.

    The MIT lab experiment is one thing. What occurs on the rotating Earth another. They are not the same and to simply parrot what you are ‘taught’, might be education, but it is clearly not wise. Perhaps the universities need to teach the students how to think. How to critique a theory to find the logical flaws in it. And of course, learning a basic 3d program might be a good idea. If you simply would visualize what you are claiming, you’d see the mistake. But like most, you lack that skill.

  29. Thanks for demonstrating my point by continuing to repeat your incorrect claims (with minor changes) until I have to give up anyway.

  30. Frank J posted on 2015-11-09 at 11:39

    Just as my uneducated ( formal that is ) mom would say. Experts – what do THEY know. Put 10 so called experts in a room. Ask a question. Half will answer one way and half insisting on the other. Seems she was right. Go to the doctor, get diagnosed then go for a second opinion. Both doctors learned the same material but have a different belief . The laws of physics are taught without experimentation because the schools are AFRAID eventually a student will prove them wrong.

  31. Half of “experts” will disagree that gravity exists or that water is wet, therefore schools are afraid students will prove the laws of physics wrong? No, legitimately proving the laws of physics wrong would result in a Nobel prize that would increase any university’s prestige.

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