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Ozone Hole Leaks and Other Tales

Filed under: — group @ 5 April 2007 - (Türkçe)

Guest commentary by Figen MekikGrand Valley State University

“But Figen, humid air feels oppressive, heavy!” students told me, almost in unison. A very treasured moment indeed. I just got a glimpse of probably a long held misconception: water vapor is heavier than dry air. So, we took out our periodic tables and calculators, and went on to calculate the molecular weight of H2O and how it compares to that of N2 and O2 (most of the atmosphere). Happy that I corrected a major fallacy, I didn’t see the rest coming.

Apparently, there are many other sinister fallacies lurking just underneath the surface of the heavy wet air idea. One student asked “is the formula for water vapor the same as for liquid water?” and was astonished to find out that it is always H2O regardless of phase, even in ice! I said “we like to keep things simple in science” and a couple of ladies giggled “as if!”

Then another admitted that he always thought water split into H2 and O2 upon evaporation which would make wet air heavy. Another student answered him with “No way man. When water vapor condenses to liquid, the molecules get bigger which is why liquid water is heavier than vapor.” So we had a long discussion about molecular dynamics of evaporation and condensation. Also, once I helped the students realize the stark contrast between what they think they know (water vapor is heavy) and something else they know from the Weather Channel (low pressure means rain), the cognitive dissonance (the psychological tension created by conflicting knowledge) drove them to question both “bits of knowledge” and to adjust their ideas. By the end of the hour, they were saying this is SOOO weird, humid air rises. Who knew!

Here are some other common and very tenacious misconceptions:

[1] Seasons are caused by cyclical changes in Earth’s proximity to the Sun. The main causes underlying this one likely are that [a] intuitively it makes sense and [b] textbooks frequently exaggerate the eccentricity of Earth’s orbit to the extreme that such an idea is logical. The problem is this misconception is extremely popular, from kindergarten to high school physics teachers. A very confused young man once told me openly “Well, my third grade teacher told me that the Earth’s axis is tilted and that is why we get different seasons and it’s winter in the northern hemisphere, when it’s summer in the southern hemisphere. My high school earth science teacher told me during the summer we are closer to the Sun and summers are hot everywhere. Now you are saying my grade school teacher was right all along. And there is all this hype about sunspot activity being the real cause behind global warming. Since the Sun causes our seasons for whatever reason, that sounds believable to me. But you say it’s CO2 in the atmosphere causing global warming. How do I know I can trust you?”

He has a point! And it is very difficult to address the inconsistencies in his education convincingly. I could have told him about my PhD and that I am a climate scientist, but that really doesn’t have much currency in such situations. So I acknowledged that he has a valid point and devoted the next month to demonstrations and data and error margin analysis to empower the students to the point that they could understand the science for themselves. We couldn’t cover coastal geology that semester because we ran out of time, but I think it was worth it anyway.

[2] The hole in the ozone layer and atmospheric pollution (including but not limited to aerosols) cause global warming. Like the previous one, this one is also very tenacious and difficult to dispel because it is often presented this way in the media and most primary and secondary school teachers share the same fallacy. Perhaps one of the underlying faulty notions here is that the Earth receives heat from the Sun, instead of radiation. So, the thinking here is that the ozone layer shields our planet from the Sun’s harmful rays and its heat. And because there is a hole in the ozone layer, the extra heat seeps in and gets stuck under the ozone layer causing the greenhouse effect. I know, yikes!! I try to dispel this misconception by explaining that though the sun is indeed quite hot, there is all this empty space between the Sun and our planet and heat travels to Earth as infrared radiation from the sun, but the Sun’s output of infrared is only a fraction of its output as visible light. Energy from the sun mostly reaches us as visible light and ultraviolet radiation. (Minor edit to remove confusion with sensible heat and radiation. Sorry about that!).

However, the notion that global warming and ozone depletion are linked is not entirely wrong. As was discussed earlier on RealClimate (Ozone depletion and global warming), original CFC’s as well as ozone itself are powerful greenhouse gases and stratospheric cooling caused by the increase in atmospheric CO2 actually accelerates ozone loss there. Even the replacement gases to be used in lieu of CFCs may have significant greenhouse warming potential. BUT, ozone depletion (“the hole in the ozone layer”) does not cause global warming.

This discussion eventually lends its way to a discussion of aerosols (see Aerosols: the Last Frontier) and although aerosols tend to scatter or absorb incoming solar radiation (hence a warming effect), their net effect is in the direction of cooling because they have a positive influence on the nucleation of clouds which increases our planet’s albedo (ability to reflect light).

[3] The greenhouse effect and global warming are the same thing. This is another yikes!! Perhaps the root of the problem here is that the discussion of the greenhouse effect in the classroom is often tightly linked with that of global warming. It needs to be explicitly pointed out to students that without the greenhouse effect our planet’s surface would be about 30 degrees C cooler and with wild differences in temperature between night and day. Not exactly habitable. But anthropogenic global warming is caused by the human-induced increase of greenhouse gases in the atmosphere since the Industrial Revolution, particularly CO2. Most of the past changes in climate on glacial-interglacial timescales can be explained by invoking changes in solar activity and greenhouse gas concentrations in the atmosphere, sure. But the warming we have been experiencing in the last few decades cannot be explained if we do not include the effect of greenhouse gases released by human activities (see the IPCC 4th Assessment SPM, and Avery and Singer: Unstoppable Hot Air, just to name a couple).

[4] Toilets flush in opposite directions in the northern and southern hemispheres. This one is kind of a pedagogically useful misconception because although it is absolutely wrong, the idea behind it is correct and it is primarily a matter of scale. Having said that, I find the Coriolis effect to be one of the most challenging topics for students to grasp as soon as we move beyond its initial descriptive definition. There is often lots of confusion between “to the right” and “to the east” in the northern hemisphere. Plus when we add another dimension to the mix (vertical) in discussing tropical hurricanes, this becomes a serious barrier to understanding. So, I try to avoid any directional terms, like east or west as well as clockwise or counter-clockwise. Not because students are too young to know a non-digital traditional clock, but because from satellite images hurricanes look like they are rotating counter-clockwise. Really can’t argue with what the students are seeing for themselves. But if we keep the terms simple, “moving objects in the northern hemisphere are deflected to the right within the frame of reference of the moving object,” it becomes a little easier to understand, though still challenging. Another challenge here is that the Coriolis effect comes across as a force and it is difficult for students who have not had physics to distinguish between a force and a deflection (an effect).

Perhaps you are now thinking “this may be true in some university in west Michigan but surely in other, more prestigious universities the students know better!” If only this were true. A Private Universe is a video documenting lingering misconceptions among Harvard graduates about the causes behind seasons and lunar phases. The problem is misconceptions are hard to detect because most students are adept at answering questions with exactly what the teacher wants to hear and with correct terminology but without any real understanding of the science. After nine years of collegiate teaching I now know to encourage a casual “say whatever is on your mind” attitude with students. This way, I am hoping to get them to inadvertently voice their misconceptions so I can address them.

And one may be tempted to think this is solely an American problem because the American system of education has been exposed to some serious criticism of late. Again, not so! It’s a global problem. Here are some examples from a couple of quick Google searches. Greek kindergarten teachers harbor deeply rooted confusion about the “ozone hole” and the “greenhouse effect;” while Greek primary school teachers think the ozone hole causes climate change. Australian university students believe a large portion of the ozone hole is over Australia and that the high rate of skin cancer is largely caused by this hole. Junior high school students in Israel seem to understand various processes within the hydrologic cycle, but believe its beginning point is the ocean and the end point is groundwater. And some Turkish in-service physics teachers believe that the moon does not rise and set while Turkish pre-service science teachers think summer is warmer than winter because the Earth is closer to the sun in the summer time.

How about you? Take this quiz to see where you stand ;) Update: Apparently the quiz has been taken off line…

I think, however, there may be some room for improvement in the wording and explanations in this quiz because some questions are very obscure, ambiguous and Chicago-centric. I would like to know what commenters think about it.

Where do misconceptions come from? Personal experiences and intuitive understanding play a large part in fostering misconceptions, and most false notions are reinforced through school and the media. I would like to share with you this delightful and brief story of how personal experiences color the judgment of a bunch of 4th graders about the nature of heat. They have a wise science teacher who broaches the topic with a question: “can you give me an example of something that is hot?” She is expecting answers like the Sun, or a stove or maybe even Britney Spears. But the students say sweaters, hats, and coats. One says “rugs are wicked hot.” The teacher says “when I touch your sweater it doesn’t feel hot.” The students say “Ooh, it’s a matter of time. With time it can be 200 degrees!” Hmmm.. Can you blame them? They spent at least nine years in cold Massachusetts winters and their parents and teachers always told them to put on their warm clothes.

Like this example, some of the problem underlying misconceptions stems from language. “Warm clothes” implies clothes that emit heat, “greenhouse gas” suggests greenhouses are warm because of their gas content, “the rise and set of the sun” suggests the sun is moving across the sky, not the earth is rotating on its axis, and “the theory of relativity” implies all things are relative when actually the theory is based on the constancy of the speed of light.

Let’s go back to our 4th grade class to see how this very experienced teacher addressed the problem. She could just come right out and say “that’s ridiculous, you’re clothes don’t emit heat, they trap the heat your bodies emit.” That would certainly save time to cover more content; instead she decides to do something else (e.g. concept/inquiry based learning for the educators out there). She says “Tomorrow I want everyone to bring something hot from home.” The next day sweaters, scarves, hats and even a down sleeping bag arrive. The teacher puts a thermometer into each one and they wait until the next day for them to get hot on the inside. The students are convinced the down sleeping bag will be 400 degrees! They rush in the next morning and quickly check their thermometers. 68 degrees! They’re shocked. But convinced? Not a chance! They are not going to dismiss 9 years of personal experience just like that. “Cold air got in there!” says one little girl. “When I sit in the car with the windows up, it gets hot. We need to hide our clothes.” So sweaters and hats get put into drawers and closets with their thermometers snuggly in them. Another night goes by. The next day they rush in and check their thermometers again. Again 68 degrees! Except one student has 69 degrees. They all applaud. Still not convinced, after all there has been indication in the right direction! Several nights go by like this. Finally serious doubt begins to ensue. So the teacher says “I want everyone who believes clothes are hot to walk to this corner” and she points left; “and the ones who think clothes trap the heat our bodies emit to this corner” and she points right. Most of the students go to the right but three stubborn ones go to the left. Guess you will always have the denialists! But no matter what, these students experienced two things more important than heat: the scientific method in action and sometimes the way something feels is only that and not reality.

So, are misconceptions barriers to understanding or helpful pedagogical tools? That will largely depend on the individual teacher’s (professor’s) style and interests. But the important thing is to [1] challenge misconceptions, [2] demonstrate their faultiness through carefully devised experiments (ideally by the students), [3] help develop multiple working hypotheses to understand the meaning of the results of these experiments, [4] devise more experiments to test and retest each hypothesis, and [5] NEVER let a student leave the classroom with a diagnosed misconception uncorrected. And, perhaps the most effective method for eradicating misconceptions at every level is going to be investing large quantities of time, money and effort into educating primary and secondary school educators. NSF has many programs that fund such efforts, but much more effort is clearly needed on a global scale.

Disclaimer: I am not an educational psychologist. I am simply a college professor and ocean/climate scientist enjoying a rich and intense teaching career in the Geology Department at GVSU. Also, my anecdotes and all my quotations are intentionally fictionalized to protect the confidentiality of students. The ideas expressed in the quotes are amalgamations of multiple repeated ideas expressed to me from students, professors and colleagues alike since I started graduate school in 1991 at Middle East Technical University in Ankara, Turkey; and the misconceptions I mention are not unique to any of my students but are listed in over 7000 published misconceptions about science.

260 Responses to “Ozone Hole Leaks and Other Tales”

  1. 151
    Craig Allen says:

    Re 132 BillOfGoods: In spite of the supposed right of freedom from big government, over-regulation etc. enshrined in your constitution, I, along with my children and millions of other people have a right to continue to live in a comfortable or at least livable environment. Perhaps you aren’t aware of the data on long term climate trends, or you live in a portion of the good ol’ US of A where the weather is normally crazy anyway or is particularly robust against global trends. But the situation is not looking so rosy down here in Australia. You can see the latest news on the long-running Australian drought here (the map at the bottom shows areas experiencing serious deficiencies or lowest on record rainfall). The situation we are experiencing may be a fluke and the scientists may all be wrong. But what if they are right and there is worse to come? You’re scared of regulation? Try living somewhere where water catchments are reaching critically low levels and you’ll get a real lesson in what being regulated means. In both Adelaide and Melbourne ‘dob in a water cheat’ is the new fun-for-all-the-family game where neighbors report on each other for crimes such as washing their cars or watering their roses. My grandmother’s garden, lovingly created over the course of 50 years is mostly dead because her tap water got too salty. My mother told me tonight that she’s given up carting water from the shower (showering with a bucket is a national sport now also) and has decided to replace her whole garden with drought adapted natives. Right now it’s all a bit inconvenient (unless you are a farmer off course) but one more dry year will see the panic setting in. We’ve had plenty of warning of this possibility but the politicians kept ignoring the warnings of scientists, saying that they were sensibly not going to harm economic interests by making knee-jerk decisions in response to doom-saying greenies.

  2. 152
    tamino says:

    Re: #148 (BillOGoods)

    In this way, only those theoretically effected will pay for the effects and not the whole of society.

    This is one of the most offensive statements I’ve ever seen. How about if those who are responsible for the effects — the whole of society — share the burdern?

    It’s folks like you who give capitalism a bad name.

  3. 153
    Figen Mekik says:

    Frederik (#99),

    First thank you for showing me how to better explain the Coriolis effect to my students. I am very familiar with the image you posted, but I think our miscommunication stems from my dominantly ocean science background. So let me clarify. In essence we are talking about the same thing: moving objects are deflected to the right in the northern hemisphere. But I like to include a vertical component to ocean motion (and air motion too since it comes up in class) when discussing the Coriolis effect but apparently I need to clarify a drag component in this picture. Gavin helped me with the rest of this explanation. All vertical motions can be thought of simply as the result of convergence and divergence in the horizontal flow and in the absence of friction (drag at the surface) there would be no convergence/divergence and hence no vertical motion. At the surface, the drag causes the winds to converge at the center of a low pressure zone. This gives ascending motion in the center of the system. In the ocean, the Ekman flux is to the right of the winds, and so in the subtropical gyre causes a convergence in the center and downwelling there. The ocean height is higher in the centre of the gyre and so the force is radially outwards. i.e. it is a high pressure system, and naturally the currents go around clockwise.

    So, you get surface convergence in low pressure systems in the atmosphere, but in high pressure systems in
    the ocean. But the convergences are not due to Coriolis alone, but due to the drag, and that is expressed differently in the ocean and atmosphere.

  4. 154

    [[Re #123: [That’s why I’m for renewable sources of energy.]
    Well, who isn’t?

    You aren’t, presumably, since you think nuclear power is the answer to global warming. And you immediately follow your rhetorical question with why you don’t think renewable energy can do it:

    [[ The problem (as we’ve discussed before) is that there’s not enough of it that can be harnessed, dependably, with current technology, to do everything that needs to be done.]]

    I don’t agree. Knowing just what we know now, we can replace the fossil fuel/nuclear infrastructure with renewables in a few decades at most.

  5. 155
    Paul Dietz says:

    you think nuclear power is the answer to global warming.

    It’s certainly an answer, one of many.

    we can replace the fossil fuel/nuclear infrastructure with renewables in a few decades at most.

    Shame about the cost of solar and lack of dispatchability of wind, though.

  6. 156
    Hank Roberts says:

    Yeah, but if we focus for a few decades on conservation, efficiency, and solar and wind, we may buy enough time to get a serious helium-3 mining operation going on the Moon.

    Google it. There is serious interest in that route already discussed.

    It’d be smart to avoid committing to all the infrastructure needed for either big coal or big fission power plants — and creating all the vested interests that would then argue against wasting money on creating a ‘needless’ helium-3 fusion system, once the money was committed to fission piles.

    Neutron activation is the problem with all the other fission and fusion paths.

    It’s a capital mistake to invest in advance of the evidence, and capital is something better not wasted.

    The money that could be spent getting a serious step past the temptation to invest in either of those two known dirty and troublesome technologies — and the savings from not having to decommission all the avoided plants — would be huge.

  7. 157
    James says:

    Re #141: [Set off a full-scale nuclear war, deliberately or otherwise.]

    I agree with at least the possibility of your reasoning re nuclear weapons, but that was my point: whatever the level of nuclear weapon use, from one “dirty bomb” to an all-out nuclear exchange, the effects (summed over the whole Earth and time in which they’ll be felt) would still be less than what we can expect to see as consequences of AGW.

    Of course you have to figure in some estimates of how likely these things are. A chain of events starting with misuse of nuclear power might possibly set off a full-scale nuclear war, just as continued CO2 release might possibly trigger feedbacks that lead to runaway GW and extinction of most higher life forms, but neither of those scenarios is at all likely. There are also some pretty obvious ways to minimize the risks, but any discussion would quickly get us off into politics.

    [… only one of the major sources of GHGs – electricity generation – could be much reduced in the next few decades…]

    However, electricity generation can, with varying degrees of effort, replace most other uses of fossil fuels. For instance, the transportation sector could shift to a mix of EVs and plug-in hybrids. High-speed electric trains could replace air passenger travel on many routes, and could haul much of the freight that is now shipped by truck.

  8. 158
    James says:

    Re #154: [You aren’t, presumably, since you think nuclear power is the answer to global warming.]

    Now how did you get that idea? I hope you don’t think that I have the sort of limited mind that can see only one possible approach to a problem – especially as I know we’ve discussed this before :-) Just to recap: I don’t think there is an answer to global warming. There are a lot of partial answers, and all of them will be needed if there’s to be any hope of success.

    [I don’t agree. Knowing just what we know now, we can replace the fossil fuel/nuclear infrastructure with renewables in a few decades at most.]

    I have to go with the opinion of the renewable energy folks (you can find the link back a few articles – IIRC you posted it :-)) who think that renewables plus conservation can only replace something like 40-60%.

  9. 159
    Hal says:

    I think the unstated issue in terms of counter-clockwise rotation of hurricanes is that if you imagine yourself as a parcel of air that is rotating around the center of the hurricane (as it appears!) then you are constantly turning to your LEFT. That seems to contradict the nature of Coriolis forces. I suspect that this issue, which has not been clearly laid out in the discussion here, is the source of students’ confusion which Figen is trying to allay.

  10. 160
    Figen Mekik says:

    Re #159: Hal: Yes! :o And I’m not doing a great job. It looks to the LEFT if you look down from space, but if you looked up from the surface it would be clockwise (looks to the RIGHT). Though as the pict Frederik posted (#100) so nicely demosntrates, deflection is always to the right in the northern hemisphere.. I had a “twist your hand up” and “twist your hand down” exercise to illustrate this in class, and it looked as stupid as it sounds and didn’t help anybody. But I tried :)

  11. 161

    I remember my sister, who was told by her teacher that the sun was a globe of glowing glass. “It says gas in the book, teacher”.

  12. 162
    Nick Gotts says:

    Re #157 James, take a look at the papers linked to at, and particularly at:

    Alan Robock, Luke Oman, and Georgiy L. Stenchikov (J. Geophys. Res, in press)

    This indicates that global nuclear war would have utterly devastating atmospheric and climatic effects – global dimming and cooling (to mean temperatures below that at the LGM 18000 years ago)and a sharp drop in precipitation, largely wiping out agricultural production for perhaps a decade, plus extensive destruction of the ozone layer. Still, at least we wouldn’t need to worry about AGW any more.

    So far as nuclear (or renewable-based) electricity generation replacing other forms of fossil fuel use: possible in the long term, no doubt, but to what extent within the crucial next 20-30 years? Even if the technical problems could be overcome rapidly, the cost of infrastructural replacement would be phenomenal – not just financially, but in terms of the increased GHG emissions involved in producing and installing that infrastructure, which would have to take place in large part before any significant shift away from fossil fuel electricity generation took place. So no technical fix, whether nuclear or renewable, is going to allow us to avoid fundamental reorientation of global socio-economic and political systems, including considerable demand reduction in rich countries – if we’re serious about preventing catastrophic AGW.

  13. 163
    beyondtool says:

    Hope someone gets this far down the thread, there is a lot of excellent discussion here!

    I found that Private Universe Video really opened up a can of worms for me. Although some of it is dated they actually went on to create a project based on the original video:

    2 years after this they revisited some of the students and created a fascinating 3 part series called “Minds of our own”:

    Every teacher should see this video if they haven’t already (especially science teachers!). It explores Piaget’s idea of constructivism in the classroom, and how children build up their world using ideas they have experienced concretely. At some point in the video the penny dropped for me and it was like I had this flashback to my teenage high school years. The reason I struggled with High School was because I was so interested in grasping the science that I didn’t have enough opportunity to gain a full understanding before the next concept was ushered in the door. By the time I reached 10-11 grades my head was full of ideas, but I couldn’t keep up anymore as more abstract understandings were required. I clearly remember my high school teacher trying to explain Faraday’s light experiments as a lead into physics and I just didn’t get it (how can light be a wave and a particle? sounded like something a zen monk could spend his life meditating on!). At that point I totally lost it, fell behind and failed senior physics. My fellow students had happily memorized the entire curriculum and they fared well on the tests. But what about basic science understanding? I had gained an understanding that the seasons were governed by the tilting of the earth, not the distance of the sun..which graduates often fail to grasp. One teacher in the series states that there is only enough time in a year to present 15% of the curriculum content properly so that students can grasp it. And we wonder why students switch off and drop many high order thinking concepts have you as an adult had to learn in the last fortnight? And yet we expect maturing minds to grasp such ideas so quickly without concretely experiencing these abstractions?

  14. 164
    Figen Mekik says:

    About the quiz:

    I had some recent interactions with the eductors at Oakland who developed the quiz, namely Mary Stein and John Coughlin. They say it has been taken off line for revisions based in part on your comments and in part on comments here:
    They also say it was developed for preservice elementary school teachers who had not yet had college level science courses which is why some of their explanations were so basic.

    I, for one, hope their revised quiz comes back on line soon as this is quite an invaluable service both to diagnose and to cure misconceptions.

  15. 165
    Paul Dietz says:

    we may buy enough time to get a serious helium-3 mining operation going on the Moon.

    You would do well to be extremely skeptical of this. The concentration of 3He in the lunar regolith is very small, something like 10ppb on average. The energy required to extract it will be a significant fraction of the energy it can ultimately produce, even assuming we had workable and economical fusion reactors that could burn D-3He (which is something like 50 times less reactive than DT). Energy infrastructure on the moon (to produce the energy needed to drive the extraction) will be very expensive, per watt, compared to energy infrastructure on Earth. It’s very difficult to see how this could ever be competitive, never mind in a few decades.

  16. 166
    Jim says:

    Re. 165

    I have to agree. Fusion is a pipe dream at this point with folks not generating enough net energy to use fusion as a primary energy source. I would love to see it realized however but after 40 years (Of admittedly hard work) it is hard not to be underwhelmed.

    We also have not reliably solved the question of viable energy storage with renewables. Current batteries are not the solution as we already have problems with toxic heavy metal pollution. (And to think of all that mercury in “green” CFLs!) And in any case, the semicon industry is not green and it is very power and resource hungry. (I would know I work in this field.) Scaling Solar will not be as cheap and clean as you think.

    People latch on to Nuclear fission becuase it is here now, and mature. I just don’t like the hazard of the spent fuel.

    Lets suppose that fusion were ready now, aside from spent fission fuel rods, fusion reactors have all of the dangers of fission reactors:
    1) Neutron activation of all components of the reactor.
    2) Loss of coolant or magnetic containment could be a disaster, with the added benefit of a massive hydrogen explosion as a worst case scenario.
    3) It is trivial to use fusion/fission reactors to bombard U238 to create plutonium to use in nuclear weapons for bad guys.


  17. 167
    Hank Roberts says:

    Paul, I realize the concerns. Buying time for something that doesn’t produce either CO2 or neutrons — that doesn’t have a huge toxic waste stream as part of the output when the whole process and cleanup are considered as costs.

    You want “competitive” — I think the next energy development we invest in first has to be “survivable” — that’s my criterion for developing a successful energy source going forward.

    If we instead use up the cheap and easy energy sources — the quick and dirty ones — we’ll be taking the easy, obvious, seductive path. No, there’s not enough power to live the way we’ve been living. Look at any city at night from the air. Measure the ‘urban heat island’ — waste energy.

    If we had to do it right — we could. Don’t we? can’t we?

    Even if it meant not spending and making and spending and making, for long enough to look beyond the quick and dirty answer?
    Even if we had to be — very, very —- conservative, and careful, and really aim for a future that the next generation or two would be able to live with and make work and leave them the huge freedom to decide when they’re so much smarter, what to build next that will take up most of the capital and create most of the costs they’ll have to handle?

    Why leave a problem instead of a pile of capital? What happened to being chary and careful and saving for future better choices?

  18. 168

    [[We also have not reliably solved the question of viable energy storage with renewables.]]

    Modern solar thermal plants store enough excess heat in molten salts to enable them to run at night and during bad weather.

  19. 169
    Paul Dietz says:

    Hank: I think you are still grossly overestimating the feasibility of lunar 3He mining. Doing it in a few decades on anything but a tiny, micro-pilot scale is just not in the cards. And competitiveness is the issue — if it requires more effort than terrestrial alternatives, like fission or solar, then it might as well not exist at all.

    You are wrong, btw, that D-3He fusion produces no neutrons. In fact, it produces at least 5% of its energy in neutrons, from DD (and some DT) reactions. The proposed advantage is that the neutron flux is low enough that the first wall of the reactor doesn’t have to be replaced every couple of years due to radiation damage. You still end up with a reactor core too radioactive for hands-on maintenance, and a reactor in which the core is far more complex, and hence expensive and likely unreliable, than a fission core of the same power.

    Why leave a problem instead of a pile of capital? What happened to being chary and careful and saving for future better choices?

    Foolishly wasting our children’s inheritances on infeasible boondoggles does them no good either, wishful thinking notwithstanding.

  20. 170
    nicolas L. says:

    Hello every1.

    I have to say Iâ??m very surprised of most of the commentaries Iâ??ve read about the « major nuclear accident still to comeâ??.
    This accident already took place in 1986 in Tchernobyl. The last report of International Atomic Energy Agency published a report in 2005 estimating the life cost of the Tchernobyl â??incidentâ?? to about 3000 people. Iâ??d have to say those numbers are quite underestimated, at the very least by a factor of ten, more probably by a factor of 100. The numbers of the IAEA would be a laugh if they were not an insult for concerned populations that still have to suffer today from the effects of radioactivity, mainly the inhabitants of the small country of Belarus (where 75% of the radioactive particles felt after the explosion of the reactor), and the Russian volunteers who worked during two years after the catastrophe on the mainly contaminated areas.
    No serious medical follow-up of the tens of thousands of volunteers have been realized after their return from Tchernobyl, mostly because of denial policy of USSR and the collapse of the medical system in Russia after 1990, but some non official numbers talk about a twenty to fifty percent death rate to this day.
    Concerning the Belarusian people, it has to be noted that millions of them were directly contaminated during the celebrations of the working day on the 1st of may 1986, when they were asked by the soviet direction to celebrate in the street while at the same time the radioactive cloud coming from Tchernobyl (at the border of Ukraine and Belarus) was passing over Belarus. To this day and due to the denial policy of the Belarusian president Alexander Lukachenko (which is considered as being the last dictator of Europe), the few scientists who tried to work seriously on the question and started to raise the question of health effects of Tchernobyl on populations are reduced to silence. Professor Youri Bandazhevsky, director of the Gomel Medicine Institute in Belarus, was put in jail for fallacious reasons after starting studies on the effect of caesium 137 on childâ??s health. And heâ??s just one example. In Belarus today, there is still a large portion of territory completely forbidden to the populationâ??s access, and people live with the consequences of Tchernobyl everyday. Local doctors living in the southern part of the country (the most exposed to radioactivity) report serious health problems for about 80% of the children born after the catastrophe, and countless (probably tens of thousands) abortions and deaths at birth due to radioactivity effects.

    I wanted to put this in the discussion, thirst because in a scientific and impartial debate like the one that has been raised here about nuclear power all elements should be taken in consideration. Secondly because I think itâ??s the best example of what policy can do to science when it gets the control of it. This is a support to all the scientists working on GW, and who try to stay away from politics and have an impartial and independent view on the problem.

    For those whoâ??d like to know more about the subject, Iâ??d like to recommend the books of Svetlana Alexievitch, a Belarusian journalist (not a scientist, sorry :) ) who as been censored and banned from her country to have raised the Tchernobyl issues.

    Keep up the good work here in RC :).

  21. 171
    James says:

    Re #170: [This accident already took place in 1986 in Tchernobyl. The last report of International Atomic Energy Agency published a report in 2005 estimating the life cost of the Tchernobyl â??incidentâ?? to about 3000 people. Iâ??d have to say those numbers are quite underestimated, at the very least by a factor of ten, more probably by a factor of 100.]

    How do you derive those numbers? AFAIK the actual, verifiable number of deaths was something under 50. The larger estimates (which it seems nobody can actually verify) basically seem to come from using a linear dose response model of radiation exposure.

    There are two problems with this: first, nobody has ever observed it, and the claimed number of deaths should certainly be statistically observable. Second, the body’s response to environmental insults is generally not linear. Instead, there is a threshold below which there is little or no response, or even a beneficial one. (Consider vitamins, micronutrients, or even water.)

    Then too, you have the example of all the other life forms in the so-called “Dead Zone” around Chernobyl. Far from being dead, it’s a nature preserve, and perhaps the most ecologically healthy one in Eastern Europe.

  22. 172
    Jim says:

    Molten Salt? Cute. It is a neat idea but is only prototyping at this point. Some potential problems though. To really use this for public consumption would require storage for more than 16 hours and a power density greater than 15Mw. (Solar Tres) It is fascinating technology (looked cool in the movie sahara too!) but it is not feasible for the scale of the problem at this time. If that 100Mw one is completed and works well I will sit up and take more notice.

    Some issues remian.
    1) more storage such that the system will run longer periods without the sun, such as periods where the sun is blocked long periods of time due to bad weather. (ie. storms hurricanes.) At this time it runs only long enough to greet the sun the next day. (They have a nice plot of it here.)

    2) Power output per unit land area is very high, and excludes this type of power generation from becoming a “cottage” power source.
    3) It needs to work during the winter.
    4) It still depends on other forms of power to keep the plant running if it has to shut down do to loss of energy from the sun and storage tank. (This requirement is very small.)
    5) Power density. 15MW production is like trying to fix hydro dam rupture with a tarp and some duct tape! Even 100MW is not enough when the average power station these days is .5 to 1 GW.

  23. 173
    nicolas L. says:

    Re : 72

    Iâ??m putting here two links if you want to play with the numbers.

    The link to the official IAEA report that acknowledges 4000 casualties:

    The link to an independent European study; that talks about more than 30000 casualties:

    I personally get my numbers from the Belarusian doctors and radiobiologists I talked to, which are not official numbers of course as long those people would be arrested if they dared to publicly talk about it, as it already happened.

    Concerning the wildlife around Chernobyl, it is true it has become one of if not the richest natural area in Europe, but mostly for one reason: there is no man anymore in a very large perimeter, a condition you can find nowhere else on the old continent. There are actually no studies about the mutation rates and death rates of animals and plants in the region to my knowledge, so I cannot say much more about it.

    Finally about the urban legend that radioactivity at low level is good for health, I think it could take a nice place in the story of scientific misconceptions. Inhabitants living in regions with granite soil (slightly more radioactive than other types of soils) are exposed to higher cancer rates directly due to radioactivity, studies have been done notably in the French Massif Central areas. Talking about France again, it is acknowledged now by the French health ministry that radioactivity coming from the Chernobyl cloud that passed upon France in may 1986 is the direct cause for higher cancer rates, notably in eastern France, while radioactivity deposits were hundreds of times lower than the ones found in some regions of Belarus and Ukraine.

  24. 174
    Nick Gotts says:

    Re #162 I’m going to partially row back from my claim that nuclear/renewable derived electricity couldn’t significantly affect the transport sector in the next few decades. Aside from high-speed trains substituting for air travel, which James mentioned, there are possibilities with electric cars that wouldn’t require as much technical advance or infrastructure as I thought. Batteries have limited range and take hours to recharge, but Monbiot attributes to “energy expert Dave Andrews” the idea of a network of battery-swap stations. Of course, neither of these ideas is going to be easy to introduce in a way that really helps. In continental Europe there are already quite extensive networks of high-speed trains, but air travel is nonetheless growing fast. Electric cars don’t have, and probably won’t in the near future, the “performance” so beloved of petrolheads (as we call them in the UK); and you have the familiar problem of very few electric cars so no battery stations so very few electric cars. In both cases, serious government intervention backed by public opinion would be needed to push up the cost of fossil fuel used in transport.

  25. 175

    [[Then too, you have the example of all the other life forms in the so-called “Dead Zone” around Chernobyl. Far from being dead, it’s a nature preserve, and perhaps the most ecologically healthy one in Eastern Europe. ]]

    Super! Then, of course, you’d have no problem moving there yourself, would you. Why not do that, and show how much you believe what you’re saying?

  26. 176
    Nick Gotts says:

    [[Then too, you have the example of all the other life forms in the so-called “Dead Zone” around Chernobyl. Far from being dead, it’s a nature preserve, and perhaps the most ecologically healthy one in Eastern Europe. ]]

    “Ecologically healthy” isn’t the same as healthy for the individual. Many of the best wildlife sites in the UK are owned by the Ministry of Defence, and are or were used by the army as firing ranges. They abound in wildlife, because the public are not allowed in – because of the risk of getting hit on the active ranges, and of unexploded ordnance. Anyone allowing their children to play there would be criminally irresponsible.

  27. 177
    Jim says:

    Correction for my post.

    the second point should read:

    2) Power output per unit land area is very low and excludes this type of power generation from becoming a “cottage” power source.

  28. 178
    SecularAnimist says:

    I would suggest — particularly in a forum that is specifically about climate change — that the question to be put to nuclear advocates who assert that expansion of nuclear power is “the answer” to global warming, or that “no one can be serious about addressing global warming unless they support an expansion of nuclear power” is not the very real question about the safety of nuclear power (e.g. pollution from uranium mining, high level nuclear waste, terrorism, plant safety, etc).

    Rather, the key question is whether their claims regarding climate change are legitimate.

    That is to say, is it in fact true that an expansion of nuclear power is the crucial thing that needs to be done to reduce GHG emissions? Would an expansion of nuclear power reduce GHG emissions more than other alternatives? Is an expansion of nuclear power the only feasible way to reduce GHG emissions by as much as they need to be reduced, as quickly as they need to be reduced? Would any plausible, feasible expansion of nuclear power even have a significant impact on reducing GHG emissions in the time frame in which that needs to happen to prevent catastrophic climate change?

    I think the answer to all of those questions is NO. And in that case, discussion of the risks and dangers and harms associated with nuclear power is entirely moot, with regard to the climate change issue.

    So, I would ask nuclear proponents who are actually knowledgeable about nuclear power technology and the nuclear power industry (paging Jim Dukelow) to outline a realistic, plausible, feasible scenario for expanding nuclear electricity generation beyond the existing 435 nuclear power plants world wide — keeping in mind that by some estimates it will be necessary to build as many as 80 new nuclear power plants in the coming years just to maintain the existing level of electricity generation from nuclear power — and then explain how their proposed expansion plan will reduce GHG emissions, by how much, and by when.

    For example, according the the nuclear industry, the 435 existing nuclear power plants presently produce 16 percent of the world’s electricity. So, if we doubled the number of power plants (which is a far bigger expansion than even what I have seen from the nuclear industry), and assuming that total electricity production and demand remains constant, nuclear power would then produce 32 percent of the world’s electricity. If all of that expansion went to replace existing coal fired power plants, it would reduce GHG emissions by some amount.

    If that doubling of nuclear capacity occurs while electricity production and demand is growing, while probably at the same time additional non-GHG-sequestering coal plants are still being built, nuclear might not reduce GHG emissions at all, but only reduce their growth. And if the expansion is far short of a doubling of nuclear capacity, then its impact would be much less in either case.

    As I have cited on other threads, recently the American Solar Energy Society published a report showing how full implementation of existing efficiency and clean renewable energy technologies (e.g. solar, wind, biofuels) could reduce US carbon emissions by 60 to 80 percent in the next 20 to 25 years. I have not seen a similar plan from the nuclear industry, showing that an expansion of nuclear power could reduce carbon emissions by X amount in X years — just repeated claims that “nuclear power is the answer.”

    So, nuclear advocates: where’s the beef?

  29. 179
    Hank Roberts says:

    > other life forms in the so-called “Dead Zone” around Chernobyl.
    > Far from being dead, it’s a nature preserve, and perhaps the
    > most ecologically healthy one in Eastern Europe.

    You’re jumping to a conclusion before the evidence is in; the work of tagging animals in and around the exclusion zone and tracking reproductive success is barely started. You can look this up in the science journals.

    Some species of birds somehow nest in the least radioactive areas (nobody knows how the can tell, yet).

    It’s quite possible the Exclusion Zone is a ‘Roach Motel’ for wildlife, they come there because it’s relatively free of human activity from all around. So far there’s no evidence that animals are reproducing successfully enough even to replace those that die there, let alone reproducing more successfully.

    When radioactive animals start showing up migrating away from there —- animals born in the Exclusion Zone that would have found all the niches occupied by other healthy wildlife, so they have to leave looking for living space — that would be proof that it’s an unusually healthy area for wildlife.

    This happens around less contaminated areas, for example the Oak Ridge Tennessee and Hanford Washington plants — they’re relatively healty for wildlife; it’s only what leaks out of burial sites that the animals pick up and concentrate.

    Seriously, when you make an assertion as though you knew it were a fact, support it with some evidence. When I check what you say is true, I find the opposite, and it discourages reliance on your postings.

    Remember, this is the _good_news about animal health:

    Transport of radioactive materials by jackrabbits on the Hanford Reservation…. 1975 –
    Abstract: A survey was conducted near waste disposal trenches … Radioactive feces, urine, soil, and vegetation were distributed in all directions….

    Radionuclide Concentrations in Nestling Raptors Near Nuclear Facilities
    TH Craig, DK Halford, OD Markham – Wilson Bulletin, 1979 – …. the same radionuclides were present in potential prey items collected near the radioactive leaching ponds and in samples of fecal material….

    Radionuclide export and elimination by coyotes at two radioactive waste disposal areas
    WJ Arthur III, OD Markham – Health Physics, 1982 –
    … Coyote fecal samples were collected near a radioactive waste leaching pond and a solid radioactive waste disposal facility and analyzed for radioactivity.

  30. 180
    James Wasvary says:

    In reference to the coriolis force. I thought that the reason hurricanes go opposite of what we expect is that they occur at the boundary of two masses behaving as we would expect, they are like a gear between two other gears and will go in the opposite direction.

    To show students that the force is real, I modified the traditional physics experiment where a student sits in a rotating chair, is spun with weights in his outstretched hands, and the spin accelerates as he draws the weights into his body. I had them hold the weights out, but then lift them overhead, simulating northward motion on the earth’s surface. As the radius is decreased, the spin will accelerate.

  31. 181
    Jim says:

    Re. 178

    I am not a big proponent of nuclear but what you said does not sit well with me.

    GHG will not be reduced if nuclear power is doubled due to demand growth keeping FF Power plants in use? If so what happens if nuclear does not double and the demand growth for power is made up with coal plants? Nuclear wouldn’t help there eh?

    Is that not the case with ANY type of power generation? If new power came from wind and solar and the extra power gained from them was used only to make up the power shortfall from increased demand, wouldn’t those coal plants still stay online?

    If new power is built at same rate as the demand icreases it does not matter what type of power generation it is. GHG would not be reduced, but they would not RISE due to the increased demand. (half the battle IMO.) The only way to decrease GHG is to build out power plants faster than increased demand for power.

  32. 182
    Figen Mekik says:

    James Wasvary,

    I am not implying in any way that you are wrong, I just can’t wrap my head around how the velocity of rotation increasing with decreasing radius relates to Coriolis deflection… I’ve been a dancer in a former life, so I know all too personally that if you want to keep spinning, you have to close in your arms, and you also have to keep your body vertically aligned (really straight); but how does that relate to being deflected to the right in the northern hemisphere, or left in the southern hemisphere. As I said, this is not a rhetorical question, rather a very honest one.

  33. 183
  34. 184
    Figen Mekik says:

    Thanks Hank Roberts!!

  35. 185
    SecularAnimist says:

    Re: Jim’s comment at 4:38pm (currently #181):

    What you are saying is correct. If new non-fossil-fuel electrical generation is brought online to meet growth in electricity consumption, rather than to replace existing fossil fuel electrical generating plants, then at best it can slow the growth in GHG emissions from electrical generation. That’s valuable, but it would not actually reduce emissions from their current levels, which is what really needs to happen. And as you say, this applies to any and all non-fossil-fuel technologies, whether nuclear or solar or wind or hydropower or whatever.

    What’s needed to actually reduce carbon emissions from electricity generation, as opposed to slowing their growth, is to immediately stop building any more coal-fired power plants, and then start shutting down the existing coal-fired power plants.

    As I mentioned above, the American Solar Energy Society released a report at the end of January, which shows that full application of existing efficiency and renewable energy technologies have the potential to reduce US carbon emissions by “60 percent to 80 percent below todayâ��s levels by mid-century”. According to the ASES report, “Energy efficiency measures alone have the potential to keep our nationâ��s carbon emissions roughly constant over the next 24 years as our economy grows” and six renewable energy technologies (biofuels in the form of cellulosic ethanol to replace gasoline, and electric power production from wind, concentrating solar, roof-mounted photovoltaics, biomass, and geothermal) “have the potential to make the kind of deep cuts needed in our carbon emissions. Of the total carbon reductions possible, 57 percent are due to energy efficiency and 43 percent are from renewables.”

    Certainly those projections should be closely examined and skeptically criticized. But my point is that the ASES has put forward the basis for a plan to reduce US carbon emissions by 60 to 80 percent by 2030, which is in line with what many scientists believe is needed to keep CO2 concentrations below 450 ppm and prevent the worst climate change outcomes, using ONLY efficiency and clean renewables.

    So, where is a similar report from the nuclear industry or nuclear proponents, spelling out a realistic, plausible scenario for an expansion of nuclear power — of whatever size — and showing by how much and how soon that expansion will reduce carbon emissions? I haven’t seen it. All I see is hand waving and blanket assertions that “nuclear power is the answer” and “no one can be serious about reducing GHG emissions unless they support a huge expansion of nuclear power”.

  36. 186
    James says:

    Re #175: [Super! Then, of course, you’d have no problem moving there yourself, would you. Why not do that, and show how much you believe what you’re saying?]

    Build some mountains there, provide decent high-speed internet service, and convince my employers that they really don’t need to see me in person every couple of weeks, and you’ve got a deal :-)

    But you’re resorting to “have you quit beating your wife” questions – as when the anti-nuclear activists ask if I’d want to live next to a nuclear plant. Of course if I answer honestly, I have to say no, because I don’t want to live next to an industrial facility of any sort. (I don’t even like living a couple miles from a geothermal plant.) Ask instead, if the only two choices are living next to a nuclear plant, and living next to a coal plant of the same size, which one I’d choose?

    So frame your question fairly: If a Chernobyl-type accident had happened in some place where I’d otherwise want to live, say Lake Tahoe, would I be willing to move there now, assuming of course that I was interested in moving at all? Then my answer is yes.

  37. 187
    tamino says:

    Re: Coriolis effect

    Am I missing something? We all agree the “Coriolis force” is not a force. But I submit that the “Coriolis deflection” is not a deflection at all. The video of a ball rolling on a rotating merry-go-round is a good illustration. The ball does not deflect; it merely appears to, because of the rotating frame of reference of the observer.

    It seems to me that objects do not deflect to the right in the northern hemisphere at all, they merely appear to. And it seems to me that the real reason for the rapid counterclockwise rotation of northern-hemisphere hurricanes is the conservation of angular momentum; as the already rotating air mass contracts, it must spin faster in order to conserve angular momentum.

  38. 188
    Figen Mekik says:

    Tamino, for sure. I’m with you 100% there as I was trying to make that point in my essay. But the more I read about this (Wikipedia included, but again I am in no way implying Wikipedia is the end all resource :) ) the more I am getting confused as people are saying there is Coriolis effect and there is Coriolis force. From my high school physics class I learned force must cause acceleration, and if things are changing direction of motion then, I guess, there is radial acceleration, so Coriolis is a force. But as you say, Tamino, nothing’s changing direction; it is just an apparent deflection. Please picture someone throwing up her hands. That’s me. If the moderators would help us out or anyone else, I’d be delighted.

    I know it seems if I write a piece about misconceptions, I should have all the answers. But I don’t and I am learning just as much and probably more than anyone. I would like to believe that everyone has much to learn, but maybe I am just making myself feel better.

  39. 189
    James says:

    Re #174: [Batteries have limited range and take hours to recharge…]

    The limited recharge rate isn’t really the problem there. Turn the problem around, and think about the amount of electric power that needs to flow to quickly recharge a battery.

    That’s one of the reasons I think plug-in hybrids are a much better solution. Most trips are within battery range, but when you need to go further, or need heat in cold weather, you use an engine and onboard fuel. This could even be a more efficient gas turbine or Stirling engine, since it wouldn’t need the torque and acceleration of IC engines.

    [In continental Europe there are already quite extensive networks of high-speed trains, but air travel is nonetheless growing fast.]

    I think that’s at least partly due to price. When jet fuel costs go up, that changes. Also, I’d thought that you really only had high-speed rail in France (with routes into Switzerland), and possibly Germany?

    [Electric cars don’t have, and probably won’t in the near future, the “performance” so beloved of petrolheads…]

    Do a search on Tesla :-)

  40. 190
    Figen Mekik says:

    Ok, and I have another question though my response to Tamino hasn’t been posted yet. When I am spinning, I certainly feel a lot of things like my center of gravity (if you are doing it perfectly it feels like your spinning axis is right in the middle of your center of gravity) and how even the slightest digression from being perfectly vertical causes tipping over in some direction.. But I thought these things had to do with one’s angular momentum. I don’t remember ever feeling being deflected any which way. Nor can I see any deflection in the mirror or on the video tape. So I thought Coriolis was a matter of scale: can’t see it in the toilet bowl, can’t see it in the dancer’s body. But maybe there are other factors here like a dancer has control over his/her body and does a lot of spotting (always looking at the same spot-the head spins last) in order to not lose balance and/or throw up on people. But again, I don’t get it. :)

  41. 191
    Hank Roberts says:

    Seems like you need to decide if you’re talking about
    spinning on an axis
    traversing a rotating plane
    traversing a rotating sphere
    and whether you’re using wheels or floating in the air

    Then stay in that same frame and understand how it works there without jumping out to a different physical system

  42. 192
    James says:

    Re #185: [But my point is that the ASES has put forward the basis for a plan to reduce US carbon emissions by 60 to 80 percent by 2030, which is in line with what many scientists believe is needed to keep CO2 concentrations below 450 ppm and prevent the worst climate change outcomes, using ONLY efficiency and clean renewables.]

    Then perhaps that’s our basic difference right there, when you say “below 450 ppm”. I think that’s utterly unacceptable: we must at least aim to get CO2 concentrations back within their historic range, below 300 ppm.

  43. 193
    Chuck Booth says:

    Re 187 Coriolis effect and hurricane rotation

    I am not a physicist or meteorologist, so I hope someone will correct me if I am mistaken here (esp. if I have misunderstood the question being debated):
    First the Coriolis effect –
    A person standing on the equator is rotating through space at roughly 1600 km/hr. That person fires a rocket toward the north pole and watches it fly away. Ignoring air resistance, the rocket moves north while continuing to rotate at 1600 km / hr, so it appears to the rocket launcher to be moving in a straight line north. Another person is standing at 45 degrees north latitude and rotating through space at roughly 800 km / hr; this person (who is very tall) watches the rocket as it flies north toward him and sees the rocket’s path deflected to the east; to that person, the rocket’s deflection is quite real. Likewise, the rightward (eastward) deflection of an ocean current heading north from the equator is quite real (relative to the sea floor), hence, it contributes to the clockwise flow of a subtropical ocean gyre.

    Now, the hurricane winds (Thanks to the USA Today’s The Weather Book) –
    Upper air winds flow toward a low pressure center, but the Coriolis effect forces the winds to right just as strongly; the result is the upper air wind flow around, but not into, the low pressure area.
    Near the ground, friction with the ground slows the wind and weakens the Coriolus effect (the magnitude of which depends on velocity of the moving object); the pressure gradient, however, remains the same. The pressure gradient is now stronger than the Coriolis effect and “pushes” the winds toward the low pressure center in a counterclockwise direction.

  44. 194
    Figen Mekik says:

    Chuck Booth,

    The first paragraph of your explanation was exactly what I thought and unfortunately taught, but Gavin told me I am wrong because the Coriolis effect has no latitudinal component. In other words, you would get the same Coriolis effect on a rotating cylinder, though latitudinal rotation rate changes become important for explaining westward intensification of subtropical gyres.

    Yep, I was stumped!! It keeps getting more and more confusing.

    [Response: Ummm… not quite. I was making a distinction between the beta effect (the change of f with latitude) and the simpler effect of being on a flat rotating plane (constant f). The beta effect is key for westward intensification of ocean currents (ie. why the Gulf Stream is much narrower and faster than currents on the other side of the basin), but isn’t necessary for Coriolis effects. Those are seen very clearly on a merry-go-around (the top of the cylinder!). I apologise for having added to the confusion. – gavin]

  45. 195
    Chuck Booth says:

    Re 194 Figen,Yes, I’ve taught it that way, too, as that is how it was explained in an oceanography textbook many years ago. Perhaps I should stick to biology… Anyway, it occurred to me that if the rocket launcher and the observer were both standing on the prime meridian (for a convenient reference point on earth), they would remain on that meridian as they rotate through space, even though they are rotating at different velocities relative to a fixed observation point in space. So would the rocket’s path follow the prime meridian, or would it deviate to the east?

  46. 196
    tamino says:

    Re: Coriolis

    I worked out the equations of motion for a particle constrained to move on the surface of a sphere. If the particle undergoes geodesic motion (so that there are no forces), while the sphere is spinning, then from the point of view of an observer who rotates with the sphere, in the northern hemisphere there is always an apparent deflection to the right, proportional to both the spin rate and the sine of the latitude. In the southern hemisphere, there is always an apparent deflection to the left. This is the Coriolis effect.

    I guess the point is that this is true when the particle undergoes geodesic motion, so there are no forces and no deflection. There is only apparent deflection, so it seems to be incorrect to say “Coriolis force” or “Coriolis deflection,” only “Coriolis effect” strictly applies.

  47. 197
    Fredrik says:

    Coriolis, interesting to see inteligent people speculate about a subject outside their expertise. A little ironic to see misconseptions from scientists in a thread about laypeoples misconseptions about science.

    It might not be that strange that people have false ideas about science?

    The coriolis force exist in a rotating (accelerating) reference frame like the earth. This means that the coriolis force must be included for everything in the reference frame to follow F=ma.

    The coriolis force doesn’t exist in an inertial reference frame like space with a spinning earth in it (a reference frame fixed in space)

    The motions are independent of reference frame but the forces that must be included is different. The coriolis force is in same way not a real force but it acts on objects on the earth and must be included.

    Direction of rotation.

    The coriolis force is a force to the right in the northern hemisphere. Some people seems to want this to imply that everything also should rotate clockwise. This is not true as I have tried to explain above and that could be found in any meteorology book. The rotation direction depends an all forces involved not just the coriolis force. The theory for the rotation direction is well known and straight forward. There are no need to think that the results are strange or contradictory if looking at the whole phenomenon.

  48. 198
    Fredrik says:

    Rotation, sink, dustdevils.

    Tamino is correct about the conservation of angular momentum. Put some water in a sink and pull the plug results in rotation of the water. The speed is higher closer to the plug, this is a vortex. The reason for the vortex (rotation) is that the small rotation (vorticity) that already existed in the water got amplified due to conservation of angular moment, the water is “pulled” to the plug and the distanse to the center of rotation is shorter and the speed thus get higher. This happens all the time and can be seen in the sink or toilet. The important thing is the convergense of the water.

    A fun experiment is to pull the plug and look at the vortex, stir the water in the other direction and look at the new (hopefully) vortex in the other direction.

    This is going to happen even if a coriolis force doesn’t exist. The same phenomenon applies to the rotation of dust devils, tornados and huricanes

    The coriolis force is to small to give any difference in a normal sink or dustdevil or (probably) tornado but the birth of a hurricane is much slower and the coriolis force is important for a hurricane.

    Thus, the fast rotation seen in for example a sink is due to conservation of angular momentum and not due to the coriolis force. The coriolis force only came in for large slow system.

  49. 199
    Andrew Worth says:

    Someone has just refered me to this site as evidence supporting the Cosmic ray theory:

    This section; “IV Solar wind and Interplanetary Magnetic Field” mentions a decline in the cosmic ray flux over the last 4 minima of solar cycles, it also states:
    “(7) Close correlation was found between cosmic ray fluxes and atmospheric processes such as thundercloud electricity, lightning production, cloudiness coverage, and precipitation. The chain of solar-terrestrial relationship was established: solar activity – cosmic ray modulation – changes in the global electric properties of the atmosphere – changes in weather and climate”

    Can anyone tell me if this claim has value or relevance?


  50. 200
    Lake Michigan says:

    My favorite one is this.

    I used to work in a pharmaceutical manufacturing facility where we used to use dry ice in certain milling operations to reduce the heat generated.

    Well, we planned to make this particular product on a Friday, but the raw materials didn’t clear the lab, although the dry ice did arrive.

    So a technician decided he would put the dry ice in the refrigerator over the weekend.

    On Monday, the look of shock on his face was a sight to see, as he opened the box of dry ice and said “its gone !!! “