Comments by "George Reynolds" (@karhukivi) on "Veritasium" channel.

  1. It is for some things, like a heavy aerodynamic bomb shape.
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  2. The problem with videos questioning the "conventional" view of physics is that they appeal to those with no basic understanding of physics at all! These people will then challenge the physics teacher in school with comments like "gravity is an illusion, not a force" even if they are unable to understand the concept of inverse square. The teacher has to try to undo the garbled version before getting back to the basics.
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  3.  @siddhantsawant272  There is nothing wrong here, but for beginners at physics, gravity can be considered as a force acting on a mass. Calling it an "acceleration" is confusing for beginners. Telling them that spacetime is "curved" does not help them calculate the period of the orbit of Jupiter! As a geophysicist I have done gravity surveys where we have to make corrections for elevation and latitude as well as the density of the crustal rocks. Even if I understand what is meant by "curved spacetime" it makes no difference to the calculations, it is almost a philosophical concept. Likewise for relativistic calculations, they can be ignored for most purposes. Offering advanced concepts to beginners who don' understand the basics doesn't help, people have to learn to walk before they can run. .
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  4. This is what Earth's climates do, oscillate between warming and cooling phases.
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  5.  @Marco-it2mr  Some "beach house"!!! But doesn't he have 4 houses?
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  6.  @baloofilmschannel  Better still, look at the sea level records for yourself, you can get them online.. You will see some showing sea level rising, some showing sea level falling and many which show a very gradual rise of less than 2mm/year over a long period of 150 years. A steady rise means no acceleration. and sea level falling means that the land is rising in some places. not so clear after all, is it? So if you're clever, pick only the ones showing a rise and add them together to get a really scary graph!
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  7. We see this all the time with athletes. Once in a while they perform exceptionally and the next time people are asking "what happened to him/her?" when their performance has reverted to the mean.
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  8. Glasses don't "see through" things, rather it is light coming in towards us that we receive as "seeing". That is one of the reasons for radio telescopes, they receive wavelengths that pass unaffected through the atmosphere.
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  9.  @glorytheman  Yes, I agree with you on that. However, it can cause problems even among "experts". For example, a science museum I visited a few years ago had a display of elements and stated that "tantalum was the rarest element". Tantalum may be the rarest "primordial" element in the cosmos, but the element is not rare in the Earth's crust, the abundance is about the same as for arsenic. I pointed this out to the curator, a PhD guy who nevertheless got shitty with me when I said the caption of the exhibit was misleading. There are also videos about the radioactivity of bananas on YT and the comments they attract are evidence of the trouble that advanced concepts can cause when dumbed-down for non-expert viewers.
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  10. A banana is a ridiculous item to use for comparison as the amount of K40 contained is so small. A human being is more radioactive on account of the K40 and C14 we have in our bodies, about 8000 Bq in all. Mostly beta radiation (which doesn't escape) plus some gamma radiation from the K40. A bag of potash fertilizer gives a better result with a geiger counter.
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  11. If you have an MRI scan you will be placed in a 1.5 Tesla magnet (some even more powerful than that). I asked the radiographer in our local hospital if anyone ever sensed the magnetic field but she said no. The Earth;s field is only 65 micro-teslas at most, so can anyone really detect that?
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  12. The spoilers ("lift dumpers" are always on the UPPER surface, while lots of other items are placed below the wing because that part if only contributing 20% at most of the lift. Every pilot is aware of the loss of lift caused by dirt or ice on the upper surface, and we're not too bothered by dirt, grass etc. of the lower surface. The wing stalls when the airflow on the upper surface becomes turbulent. The Newtonian downward deflection is just a distraction!
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  13. You weren't listening, were you? It's not about solid iron bar magnets, it's about self-exciting dynamos.
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  14. It is rising, but at less than 2mm per year, his beach house is safe for a few centuries!
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  15.  @baloofilmschannel  Do you know what the average sea level rise is since the end of the last Ice Age maximum 20,000 years ago? It was 120 metres, that's 6mm/year average. If it is 1.7mm/y (NOAA figure) now, then it has slowed down. Why pick 1970 as your starting point?
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  16. The interesting thing about Ramsar is that the incidence of cancers is not any higher than anywhere else! So the mantra of "no safe level of radiation" is once again disproven.
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  17. Table salt is sodium chloride, a compound of sodium and chlorine..
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  18. Everyone in Japan has a geiger counter - no worries!
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  19. Absolutely agree. Science works by disproving theories and speculations do not disprove anything.
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  20. The test is 99% sensitive, so if 100,000 people who have the disease are tested, then 1% or 1000 people won't test positive. However two independent tests change that scenario as the ones who don't test positive will not be the same for both tests.
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  21. Easily disproved!! This "research" was actually published by a German university. A colleague who has a dog and a compass thought I was kidding him until I showed him the publication. So he spent the best part of a year recording the orientation of his dog which poops on every walk and plotted the results, a random set of orientations. The journals and scientists must be desperate for publications, I guess.
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  22. In the fish markets around Fukushima they actually test the food for radioactivity as it is the only way to regain the public's confidence. As in Chernobyl, they trained science teachers and supplied them with lead shielded containers and detectors to measure the radioactivity. My nephew even sent me a box of rice cakes with "Fukushima Rice" printed on the label. They tested zero so I ate them!
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  23. The bees see UV which we can't see, so they probably see a greater colour range than we can even imagine! The video had to use some tricks to demonstrate what we might see if we could see in the UV band.
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  24. A friend, who lectures on economic geology, published an article on mineral deposits in Europe and put a dot for "copper deposit" on a remote island where no mineral deposit exists. He wanted to see who else would copy it in their publications. Now, 40 years later, that dot still appears from time to time on similar publications - replicated rubbish!
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  25. Conspiracies and cartels are often invoked to explain similar behaviour on the part of rival businesses. However, the economic theory of "oligopoly" has an alternative explanation which doesn't require any nefarious activity at all. Three service stations are competing in a small town. The prices are visible to all and one of them decides to increase prices. The others will watch to see if business decreases or stays the same. If they see that the rival is still doing the same business at a higher profit margin, then they will follow suit and increases their prices as well. Likewise, if one lowers prices and seems to be doing better, the others will follow suit. No need for clandestine meetings or skulduggery! It means that the market is not competitive, but rather based on "signalling". How to recognize oligopoly? - look at the advertisements - they will always have claims of better products or services. Monopoly and competitive markets hardly need advertisements at all.
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  26. There are guys in those countries on the equator who do this "experiment" with a bucket and a basin for the tourists 100m north of the equator and then move to 100m south of the equator and get the opposite result. They charge $10 for the show!
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  27. Easiest to comprehend. We all know about medical screening and the fear of the result coming back positive. Even medical people get it wrong and make the wrong diagnosis. Coin flipping, selecting drawers in quiz programs, eye-witness accounts and marketing studies are also used as examples, but the medical ones seem to give the best explanations.
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  28. They are to be found in all the political parties!
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  29. Once upon a time the scientific consensus was that there were no Ice Ages (but Louis Agassiz was eventually vindicated), there was no continental drift (but Alfred Wegener was eventually vindicated) and that the earth was only 100 million years old from Kelvin's heat loss calculations (Arthur Holmes showed that radiogenic heating made the earth much older). The climate has always been changing as shown by the geological record and we are in an inter-glacial period within a longer series of cyclical ice ages, to which we are destined to return "soon" (10s, 100s, or 1000s of years, who knows?). As with all science, look at the evidence critically, be sceptical of predictions, especially from computer models, and keep an open mind, unlike politicians, celebrities and religious leaders!
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  30.  @Marco-it2mr  Not just one ice age, there have been a sequence of several and they are long. We are still in the quaternary ice age, just now in a short inter-glacial period. Has anyone figured out what eneded the Younger Dryas cold period? According to Greenland ice cores the global temperature may have risen as much as 10C in a short a period as ten years. Agreed, mechanisms are always harder to account for than the actual observations themselves, however atmospheric CO2 has been between 4000 and 8000 ppm for most of earth's geological hsitory. The low 400ppm we have now is not much above that required for plant life, about 150ppm and during the ice ages dropped to as little as 180ppm. A return of the ice age would definitely lead to mass extinctions, mainly of humans as we flee towards the equator with famines and violence leaving behind our food/energy/transport infrastructure to an advancing ice sheet!
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  31.  @Marco-it2mr  By the way, Aarhenius is a chemist and a distant relative of Greta Thunberg. Vindicated by whom and how?
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  32.  @Leafsdude_  A chemist is an expert on climate change then?
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  33.  @Leafsdude_  Do you know when he was alive? More than 100 years ago! Science has come a long way since then. Incidentally, the absorption of IR by CO2 is more a physics issue than a chemical one.
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  34.  @Leafsdude_  Yes, he was physical chemist, worked on reaction rates etc., I have a degree in chemistry as well as in physics. But in his day they hadn't discovered the neutron, only had vague notions about quantum mechanics, didn't understand ice ages, no ice cores from Greenland, no knowledge of past climates from the geological record, no satellite images of Arctic ice extent and did not understand isostasy. Early days for climate science, yes.
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  35.  @Leafsdude_  Well, he thought that a drop in CO2 caused the glaciations, and now we know that it does not. Rather, a combination of the Milankovich cycles and solar variations are now seen as the cause. The drop in CO2 is a result, not a cause and is due to cold water absorbing more atmospheric gases. Shows how little science is actually understood by climate scientists!
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  36.  @Leafsdude_  So sunspot cycles of 11 years (and other periods) do not represent solar activity? You heard of the Maunder Minimum. I suppose? Greenland ice cores show that CO2 variations lag the temperature variations (from oxygen isotope information). Of course climate "scientists" do not like facts that disagree with their per narrative. I'll leave you to your "beliefs", I prefer evidence.
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  37. The Concorde had a radiation meter on the dashboard. The pilots had their rosters determined not only by hours but also by radiation dose.
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  38. Nit-picking perhaps, but the dose that will kill 50% of those exposed is usually given as 5 Sv. Google on the Goiania accident in Brazil to see who survived despite large doses.
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  39. The 67 year old at the beginning had it right but inverted the calculation. It is one year divided by the remaining time to live that makes time appear to run faster. When I was 30 a 2-year contract overseas seemed to be a long posting, an eternity! Now I realize it was just a short period of time.
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  40. They could, but it would have to be silvery and not very attractive. A molecule that absorbs UV and is transparent to visible is hardly noticeable. I wasn't very convinced about sunscreens until I spread a little on a yellow fluorescent pad and shone a shortwave UV lamp on it - the fluorescence was completely gone and the pad appeared black, like the presenter's face! I tried different grades of sunscreen and the best strategy is to buy the highest grade, the lower grades are just more dilute.
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  41. Everyone in Japan has a geiger counter and are very knowledgeable about radioactivity. They don't listen to politicians, they listen to scientists and radio-medicine experts. Remember, they know more about atomic bombs than anyone else!
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  42. It can behave like a wave - e.g diffraction. Why does a laser beam stay very narrow whereas a torch - even a good one - has a beam which diverges? Wave theory explains this perfectly.
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  43.  @simulacrumdei6462  You answered your question in the last paragraph "light is a wave in certain models", yes that is exactly what I said also. Btw, infra-red is also light and it is absorbed by clear glass. Visible light is only a tiny part of the electromagnetic spectrum. Radio "waves" are much more like waves as you understand them, while x-rays and gamma rays are more like particles. Just a matter of scale and the devices to detect them.
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  44.  @simulacrumdei6462  So you agree, radiated electromagnetic energy can act both live waves and like particles. Planck's constant links them both and as quantum mechanics shows, we cannot think of these things in terms of simple domestic analogies.
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  45.  @simulacrumdei6462  Great! Have a nice day!
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  46. Yes.
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  47. They do wash them but adding "optical white" (a white fluorescent substance) makes them "whiter than white!". Now where did I hear that phrase...?
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  48. Air-powered turbine, no magnetic components.
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  49. Really stupid use, a banana is so low everything looks enormous by comparison.
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  50. A better comparison is a chest x-ray.
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