studiot

Since you asked the question but quoted two hardly related statements of mine I don't know to which you are referring. But I sat some of those Cambridge exam papers and that is what we were told at some point. I see no reason to doubt the veracity of the examiners. As to the second point I have some manuals on technical writing and layout describing exactly this subject. I believe there are many such available. As to the rest of my thoughts and this thread in general, you seem disinterested. I think you are being unfairly dismissive of anecdotes. A great many scientific discoveries were the result of anecdotes. Penecillin was the result of a single one.

It is not suprising that you have reached some untenable consclusions since you have some flawed assumptions. Since we discovered 'techtonic plates' (do you know what they are ?) there has never been a proposal of only 1 plate ! The largest plate of all has almost no land on it. All the plates are very ancient. The plates do not float on magma. If you read exchemist carefully you will see he said that Both of these are solid. You need to a go a long way further back in time than Pangea to understand the development of the present arrangement. We know the plate have been there for a very long time and that they have moved about (principally by rotation , not as popularly described by translation). What we don't have yet is a well confirmed theory of how the motion is driven, although there are of course several promising hypotheses.

Yes asked as a question I think the answer must be yes they have changed, sometimes getting larger, sometimes getting smaller. However did you not originally posit it as a hypothesis? Which is why you have been badgered for evidence. I think that books have varied over time ins both size, weight and layout for a variety of practical historical reasons. Centuries ago books were rare and generally quite large and heavy. They also often had plenty of colour and quite a few illustrations. Of course this was all had done. The advent of printing and better paper reduced the size of the books but also did away with colour almost completely. They were still quite heavy as paperbacks did not come in until the late 19th century. During the 20th century we had two major wars and I have books from both periods which are 'economy' versions to save material. These have very flimsy thin paper a reduced typesize and very little white space on the page. Technical books were usually still hardback, but paperback versions and even further miniaturisations were available for travellers. However a lot of work was done mid century to determine the optimum 'white space' for readability. Interestingly the University of Cambridge adopted a peculiar shade of light green for their exam papers because they found out empirically that this colout resulted in the lowest numbers of candidates freaking out at the sight of the exam paper. The final part of the 20th century has brought richer times along with a great deal of presentation theory and vast technological capacity to print. However an exception being Dover which generally reduced the size, print and construction quality of older publications but at least reissued them. So yes, I would agree that sizes have expanded at the moment, perhaps a little too far and a little too expensively. No doubt things will change again in the future. Looking around today I have quite a few Schaum texts, they all seem to be about the same size and format, whatever their age. I have two very modern Geometry books one the size of a nomal novel by Roe and one the size of a Schaum book. But it really seems to be Earth Sciences that go in for the super large. Perhaps that harps back to their heritage in cartography and atlases. At any rate I appreciate the larger photos and other graphics material they offer.

Oops yes they were full of Christmas spirit. Sorry. That should have been grammes.

Could you ? Calculus was mentioned late in this thread. Consider Hobson's calculus (Theory of functions of a real variable) Volume 1 (originallly1907) My third edition 1927 736 pages 190 x 260 x 40 mm 1496 kg. Volume 2 My second ed 1926 780 pages 190 x260 x45 mm 1547 kg Both bigger than either my modern Setwart or my Finney. How about Wells - Structural Inorganic Chemistry My 1962 3rd edition weighs in at 2150 kg 1055 pages at 170 x240 x 80 mm.

Surely it's because the short leg on tables and chairs is getting shorter . Merry Christmas everyone! 🙂

Thank you for your detailed response. I think perhaps it is over pessimistic although I note the difference in students over history. It is, however , hard to get historical data, especially for a non specialist historian. Here is some I have managed to find This is a table of the % of students going to higher (University) education in the UK at various dates. 1950.............. 3.4% 1970.............. 8.4% 1990..............19.3% 2000.............33.0% As can be seen the numbers have increased tenfold over the second half of the 20th century. So the makeup of the group in 1950 is widely different from that of 2000 with those would have been included in 2000 swamped 9 : 1 by those who would not have been there in 1950. It is interesting to note that the maths teacher I was referring to had never had a pupil getting less than a 'B', out of pass grades A - E and an impressive record in the further Maths of the Oxford and Cambridge entrance exams.

I came across this short but brilliant, 4.5 minute talk from the BBC about the subject of misinterpretations. Answers here to refer to most of the fallacies we see all too regularly at SF. How to avoid falling for the ‘gambler’s fallacy’ - BBC Ideas

Note swansont's first response, I have emboldened the relevant part So you are both working in the frame of reference of that individual atom. If you want to reconsider from another point of view (Earth) you will need to do the transformations.

Nor have you posted any helpful summaries as requested so I doubt you will get many responses.

I can't see why not.

This seems to be a sequel to the researchgate article you posted a link to earlier in the year, from the same author. The general concensus of the first article was that it was fanciful nonsense. Why would we expect anything different from the second ? You should also realise by now that we need sufficient summaries of the points to comment. I will tell you that Penrose offerered a very much non mainstream interpretation of some of the difficulties inherent in Quantum Mechanics suggesting interaction via the observer's brain. But I stress this is non mainstream and raises more questions than it answers so I cannot advise pursuing it.

Not only was your chemistry question answered by professional chemists or materials engineers, but you were offered a tried and tested simple rapid and reliable method of destroying the drives. Yet you couldn't be bothered to reply to any of the members who took the time to answer. I consider that rude and disrepectful towards those members.

I know that you are actually talking about "are indeed crafts of some sort from another place", and to this I would reply they are reflections of another dimension or set of dimensions as my explanation. But The question has been raised here as to whether any extra terrestrial life we encounter is more or less intelligent than we are. First observation to consider. How many intelligent species are there on Earth and how many small and microscopic species ? Second observation to consider We know that such small life can tolerate extreme conditions way beyond our own ability. Also some of these have had the ability to lie dormant for thousands of years and then revive or be revived. Both of which lead me to believe that it is much more likely that these characteristics would help such small organisms in crossing the distance from far off places. So I consider it much more likely that our first meeting with alien life will be with a less intelligent form.

Yes that's the story, though I seem to remember it was slightly more detailed when I first read it. +1 I have never heard of Pandora's Legions , though if there are more like this one they could be good. You link give 2002 as a publication date, but I first read this one in the mid 1960s. I used to look forwards to receiving the Gollanz Worlds Best SF annual (book) every year at Christmas. This would have probably been in the 1966 or 67 one.

Thank you to both of those who replied to my post. The point about thestory in the second part of post was that humans were more intelligent but wated it squabbling amongst each other. I wish I could remember the name of the story. It was really good.

Dutch find 'anti 5G' devices (dangerously?) radioactive. Anti-5G braclets found to be radioactive https://www.bbc.co.uk/news/technology-59703523

Indeed you did. But John is right that you seem to be a bit confused about what is an isotope. Perhaps you are mixing this up a bit with allotropy or perhaps it is just a language difficulty. You also mentioned physical properties only. Physical properties are rather more affected than chemical ones because the extra neutrons add extra mass, but not charge. So properties that depend upon atomic or molecular mass such as colligative properties do vary a bit. International tables such as Lange give values for these for different isotopes where they are known. Within the atom most electron orbitals stay the same and the number of electrons stays the same to spectra from these (X ray and UV) are pretty much the same, as are the actual chemical reactions involved. So dielectric and magnetic properties that depend upon electron spin will be unaffected but NMR spectra are changed. https://www.osti.gov/biblio/6389648-proton-deuterium-tritium-nuclear-magnetic-resonance-intramolecular-hydrogen-bonds-isotope-effects-shape-potential-energy-function But IR spectra are dependant on vibrating atomic masses so will change the most. As already noted by exchemist mass spectra are clearly affected and a very important method of both istope detection and separation. However some bond strengths and/or angles can be altered. https://pubmed.ncbi.nlm.nih.gov/15137048/

Or just very long lived. or the perhaps the Scifi story in Analog SF is true. That is the one about invading monkeys from outer space. A monkey scientist wrote a paper entitled 'why the loptails don't have space travel'

Interestingly we have the following figures. Estimated mass of continental crust (ie mass of Gondwana) is 2.20 x 1022 kg Mass of existing Moon is 7.34 x 1022 kg

This is about the most ineffecient learning method I can think of, especially if you are learning for yourself. The sheer amount of material to learn is far greater than can be simply looked at in more than one lifetime. So everyone needs some reduction scheme. We periodically have those who ask the (sensible) question "If I am learning for myself how to I go about it ?" And we try our best to help them. But that would be a topic for another thread if you are interested, please start one. You might be pleasantly suprised at the response.

So why are you trying to tell me 'what I was taught' ? You have no knowledge of any 'teaching' I may or may not have received or how I received it. We actually have a couple of self taught members here with impressive knowledge, one has a knowledge and understanding of Physics well up to postgraduate level. These members also command great respect because of the attitude in being prepared to listen as well as offer their thoughts. In turn others are interested in their thoughts which are generally well worth listening to. The rest of your quote was question about imaginary numbers. No I was not thinking about imaginary numbers. You can use the decimal system with imaginary numbers. But there are numbers called irrational numbers and others called trancendental numbers that cannot be expressed in the decimal system. However some can be expressed in other systems. For example the number 1/3 cannot be fully expressed ind ecimal, but can be in a ternary system. Furthermore the numbers useful for counts can all be expressed in a decimal system. For example the number one hundred and one is exact. As to you examples about apples, you are trying to preach again instead of finding out. Isn't find out truth more interesting than holding to being wrong? How many electrons are there in a helium atom ?

Thank for telling us. +1 We should all do what we can to progress the situation, even if it is just swapping data. I'm glad someone reads my posts properly. +1

It would be better if you listened a bit more and preached a bit less. The highlighted statement in you post is just plain wrong. There are many quantities in Science where the unit is 'counts'. In that case the unit is exact to any number of decimal place you care to mention. You do also realise there are many other numbers than are present in the decimal system ?

I've seen nothing yet to make me think you understand those quite difficult concepts you are throwing about. Energy Infinity Singularity They all have very particular meanings in Science that are similar to but much more restricted than in general English. Please also take note of this excellent statement by swansont. +1