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A Science Self-Test - Just For Interest

Just For Interest. Try it from your existing knowledge.
No cheating by looking it up!
Please: No publishing answers until I have given them in due course, to be fair to anyone else trying seriously to test or extend their own knowledge. 

25 Basic Science Questions with an environmental slant, now you have saved the planet and whales, achieved zero-carbon by last Michaelmas, and are walking everywhere with a paper shopping-bag-for-life autographed by Aunty Greta.

 No trick questions but some are worded slightly indirectly; most are simple , some obscure; but all are of upper school- or interested lay- level. I am of course aware there are Answermug users with a far deeper, possibly professional, knowledge of these subjects than mine!

I would also agree that whatever is or is not happening in the world, we cannot be complacent. World-wide we are heading for very serious difficulties whatever those turn out to be; and as some of these questions suggest, neither the problems nor "obvious" solutions are as simple and trouble-free as often portrayed.

 Note: As you would expect on an international site in 2020, all the units are Système International (SI), and by their correct abbreviations or spellings (French).


1. The relationship between Energy and Power, and their units, are?.

2. Two electric kettles of similar design but one rated at 1kW, the other at 2kW. Neglecting losses, which if either kettle uses more electricity to boil 1 litre of water from 10ºC? Why?

3.  The fundamental property of energy is….?

4. Name THE one metallic element fundamental world-wide, to virtually everything we own or use, however indirectly.

5. Which two minerals are vital to extracting that metal from its ore? (Hint – the ore is the element’s oxide, with impurities.)

6. “Keep the oil in the ground!” cries Miss Tornberg, demanding no more fuels from petroleum. What has she missed?

7.  “Noise pollution”: Industrial health and safety regulations impose noise limits, or personal protection against harmful noise levels, so the sound has to be measured.
Sound, vibration, electrical and other signals can be measured on relevant decibel (dB) scales. Airborne sound’s dB scale is “referred to” a Pressure Level of 20µPa (20 micro-Pascals), i.e. that is its 0dB point. What is particular about that staggeringly tiny pressure; why not make 0dB a nice tidy 1Pa, 1µPa - or 0Pa?

8.  In engineering, “Efficiency” means…?
9. For ordinary cars, place in ascending order of energy-density (“amount” of potential energy with respect to the weight or volume of its carried source – or if you like, the car’s
range):  Diesel, Battery, Petrol ("gasoline" for our American readers).

10. Name the missing " X "in these ISO- “Preferred” divisions and multiples of the metre: nanometre, micrometre, X, metre, kilometre?

11. “Plastics kill marine life!” Do all? And by poisoning or by physical form?

12. The effect on sea-level if the Artic Polar Ice-Cap alone were to thaw, would be?

13.  “Cattle emit methane!” Yes, but what is the campaign flaw?

14. Are plastics “recyclable” just as material?

15.  This is a quote from a  real advertisement for certain ear-phones claimed to protect the user: "[conventional] electrical [earphone] leads conduct radiation”. What is/are the error(s) there?

16. By the modern, official terminology, what does the “ºC” for temperature, as in Q.2, stand for?

17. This is a harder one, I admit: can you define the ISO-”preferred”, Pascal unit of pressure (as in Q.7) by its component SI units? If so, do so!

18.  An item of 10kg mass is taken to the International Space Station. What is its mass there?

19. Which two nations presently lead the world in predicted, increasing rate of national conversion from generating electricity by fossil-derived fuels to “renewable”, particularly wind-power? (According to a Bloomberg analysis I recently saw quoted. It surprised me, I admit!)

20.  You would expect a major oil-company not to frighten its investors by pessimism; but by present extraction rates, BP has now estimated the world’s currently-known reserves of oil and coal to end in only how many years time? (Note the adjective but also that the world's population and demands are both growing very rapidly.) 

21. The entire climate-change debate is pretty toxic, but if climate-change either way has any entirely-natural component -  can humanity affect that natural component?

22. Suppose a developer gives all homes in a new housing estate, ground-source heat-pumps powered by domestic solar-panels and batteries. Basic weakness?

23. Name the type of energy that has been and will continue to be fundamental to human activities and creations, however indirectly, since prehistory.

24. What would be the main negative consequence of supermarkets not shrink-wrapping foods for sale?

25. How did Early Man (both our own species and the Neanderthals) cope with climate-change?X


Posted - January 11, 2020


  • 17168
    But you probably really knew the answers.  I, of course, could only guess at a few and the others had to claim no Inglés.    
      January 12, 2020 4:39 PM MST

  • 43677
    Oops...I answered them here to impress myself. Deleted. Sorry. Some of them are vague and don't give enough data or none at all. Some are not researchable. I missed number 17. This post was edited by Element 99 at January 12, 2020 10:38 AM MST
      January 12, 2020 10:17 AM MST

  • 3637
    Some are "vague" because they are not merely single facts or definitions. However I tried to ask each clearly whilst concisely, and they all have the data needed and meaningful. If you try to dig too deep you risk adding complexity so missing the point.

    I did admit Q.17 might be tricky because pressure is not something most of us need to measure very often; but it was still only a "what is a..?" question, so I thought it not too difficult for anyone knowing SI units. Even my car tyre-pump has a mega-Pascal scale (though I use its p.s.i. one!)

    I thought the hardest would be that on sound-measuring, but there was no catch to it, and it might have yielded to a guess based on the stated relationship to protecting human hearing. Despite the numbers and units it did not ask for calculations.  
      January 12, 2020 7:08 PM MST

  • 3637

    I think one or two thought it an exam; and one or two missed the point that I meant some questions to seem vague as they have no easy answer. I knew not everyone could answer every question but I was not testing anyone – I didn’t ask for results - nor wanted to trip anyone up.


    The units: The Metric System was invented in post-Revolutionary France to replace a morass of regional and trade measurements with a decimal system based on the litre (l), metre (m) and gramme (g).

    The system spread to facilitate trade, with the UK being among the last to convert, in the 1970s, for joining the European Economic Union (now the European Union).

    Subsequently the International Standards Organisation (ISO), in which almost all countries participate, developed the Metric System to the Système Internationale (SI), mathematically coherent but with some units difficult for everyday use. To ease that, the ISO allows certain “non-preferred’ units, including the centimetre (cm), the Bar (B) and the degree (º) for angles – the “preferred” angular unit is the Radian (rad).

    The USA is almost now alone in retaining the old measures for all everyday domestic trade. The UK retains the Statute Mile, the Pint but only for dispensing cask and keg drinks in pubs; and allows inch-dimensioned materials and items in the sizeable trade supporting machinery-preservation and model-engineering.


    1. Energy: the  joule (J). Power: the Watt (W). Power is the rate of energy conversion, so 1W = 1Joule per second (J s-1). 

    Both the J and W are "Derived Units", meaning they are defined by the kg, m and s; three of the just 7 basic SI units. It is this "family tree" effect that gives SI its mathematical coherence.

    2. Same consumption. To raise the temperature of a given mass of given material by a given step takes an amount of energy set by its own Specific Heat.

    3. Energy can be neither created nor destroyed – only stored, transmitted or converted.

    4. Iron – from which, all the many forms of Steel. Virtually everything man-made involves iron or steel, intrinsically and/or in manufacture, transport, etc.

    5. Coal and Limestone. Iron ore is iron oxide (rust), needing smelting at high temperature in a blast-furnace. Carbon, as coke distilled from the coal, is both the fuel and sequesters the oxygen, reducing the ore to iron. The limestone melts and acts as a flux to separate the impurities (sand, mainly) from the molten ore.

    6. No more petroleum means no more derivatives giving a wide range of chemical raw materials for a huge range of non-fuel products on which we all depend. Many have no satisfactory substitutes.

    7. Sound in air measurements are related numerically to human hearing.

    That 20µPa Sound Pressure Level (SPL) is the faintest the fully-healthy human ear can detect.

    How staggeringly small? One Bar, for everyday use like tyre pressures, = 100 000 Pascals.

    So 20µPa = just 1 / 5000 000 000 of atmospheric pressure.

    In words, one-five-thousand-millionth… That puts a new light on the whispered sweet nothings!

    Decibels and ears work logarithmically, so an SPL of 1Pa is 120dB re 20µPa, often quoted as The Threshold of Pain, though I have seen this given other values in different texts.

    1µPa is the 0dB reference pressure for marine acoustics and sonar.

    0Pa (absolute silence) would not work because it gives an inadmissible division by 0 in the conversion to decibel equivalents.

    8. Efficiency = Useful Power out / Power in. Usually converted to a percentage. Nothing can be 100% efficient!

    9. Lowest energy-density: battery-electric cars, by far. Then petrol; diesel highest.  

    10. X = millimetre. The non-preferred cm is common for clothes sizes and the like but used in  technical fields only in a very few, special cases such as the cubic centimetre (cc) for chemistry and engine specifications.

    11. Certain plastics only, by form only. Some are fine granules (‘micro-beads’), some weather to tiny particles. These, and polythene bags, choke the digestive systems of animals that mistake them for food. Moulded can-binding rings, lost fishing equipment, etc, kill by entanglement. Otherwise, solid plastic waste items are mere litter.

    12. No effect. The Arctic Ice-cap is floating sea-ice, melting with no water-level change. It is terrestrial ice that controls sea-level.

    13. Methane is produced by digestion or decomposition of vegetable matter, so all herbivores, omnivores, peat-bogs and compost-heaps produce the gas!

    14. Certain thermoplastics are granulated, melted and re-moulded. Thermosetting plastics cannot be recovered, though perhaps could be powdered to a bulking agent for new mouldings. The most difficult waste would be scrap glass- and carbon- fibre mouldings.

    15. The two errors: the radiation being implicitly harmful, and the phrase "conduct radiation". The trader is exploiting ignorance.

    The “radiation” here is the normal electromagnetic field around the leads, created by the signals. It is extremely weak, of audio frequency-range, and harmless. Energy can be conducted or radiated, not both at once; but some of that being conducted may be lost as radiation from the conductor.

    16. ºC = degrees Celsius. No longer Centigrade, officially. It's only a name-change and ‘Centigrade’ is still common colloquially.

    Strictly speaking, SI uses neither. It uses ºK (kelvin): same "size" degrees but from Absolute 0, about -273ºC. That avoids needless negative numbers in technical calculations; but for practical, everyday purposes we use the familiar behaviour of water: freezing at 0ºC, boiling at 100ºC.

    Water also has the vital and unique property of its density reaching its maximum at 4ºC, hence why ice floats. If you think this a purely academic point, think again - "deeply".  

    17. I did warn this is a tricky one – but this is AM’s Science section!

    The Pascal (Pa) is equivalent to 1 Newton (N) acting on 1 Square Metre.

    Then, 1N is the force generated by a mass of 1 kilogramme under the acceleration of gravity on Earth, usually taken as 9.8m s-2.

    Note that the kilogramme, not gramme , is the basic unit. It is a difficult concept, not helped by the ISO naming some derived units, like the Pascal and Newton, after people  (pioneering scientists)! 

    18. 10kg! Its mass has not changed, just its weight, which has become negligible. Theoretically it will still have a very tiny weight thanks to the ISS having its own mass so its own, albeit extremely weak, field of gravity.

    That led me to wonder, if the ISS became abandoned for a long time, would loose objects floating around inside it slowly “fall” towards the craft’s centre of mass?

    19. The two nations: The People’s Republic of China, followed by the United Kingdom. This did surprise me!

    20. Oil: 50 years. Coal: 100 years. Future discovery and use rates are hard to predict; hence the caution; but many analysts now forecast oil demand to peak before 2040.

    21. At a simple level, no, but whilst human activities cannot stop natural climate-change they may alter its rate of change.

    22. The flaw shows if each home extracts heat from the ground around the well, faster than its natural recharge; especially in Winter and where several hundred closely-spaced homes are all essentially refrigerating the land under them.

    23. The fundamental energy is heat: cooking, survival, processing ores, metals and ceramics, powering transport… Few human activities do not involve heat somewhere.

    You might have said ‘light’ and I thought about that too. We are diurnal and light is vital to us, but does not itself process food or metals, or protect us from the cold.

    24. Considerably more wasted food. Foods are shrink-wrapped for hygiene and to keep them fresher for longer by slowing decomposition. It's one of these problems whose obvious answer only raises more problems - nothing is as clear-cut as it seems.

    25. Probably, fairly easily. Early Man would not have worried in depth about climate changes despite living through major ones. The changes were slow enough to produce at most, folk-memories for the far fewer people about, who lived very simple lives, and could adapt or migrate according to conditions.

    The Neanderthals were mainly Southern Europeans, who during the Last Glacial Maximum were away from the Arctic tundra of Southern English and Northern French latitudes.



      January 12, 2020 4:34 PM MST

  • 1152
    I partially disagree with #6.  We can build up plastics from almost any source of carbon. We can even make liquid motor fuel from the CO2 and water vapor in the air.

    Of course, we cannot do these things as cheaply as we can from petroleum, so such methods are currently not economically practical.

    I partially disagree with #13. While it's incontrovertible that all the things you mention do produce methane, it's more problematic with cows because the huge grain/water/energy inputs which go into raising methane-farting cattle make cattle production a significant issue for climate change. If the world went vegetarian, we could probably ignore peat pog methane emanations. 

    I slightly disagree with #21. There are natural climate forcing phenomena (e.g. the Malinkovitch cycles in the Earth's axial tilt) which humankind (and cockatoo-kind) cannot affect. But I've read if every man-made structure on the Earth was retrofitted with a white roof, the change in Earth's albedo would reflect enough energy back into space to counteract the expected effects of greenhouse gases. Albedo is a natural property of the Earth which human beings can influence. That's the only example I can think of, so it may be an exceptional case.

    Otherwise, I was correct on 19 of them.

      January 12, 2020 5:11 PM MST

  • 3637
    19/25. Well done!

    Oh yes , I knew some of the questions are not hard-and-fast "What is...?" types.

    I did say, alter rates of change, not stop; but whilst I take your point about white roofs I can't see it ever being practicable - nor very environmentally-friendly in terms of the vast amounts of necessary materials.

    The matter of cattle actually has a strong national aspect, I have discovered, probably due to geography and climate. Some countries' farmers need to feed their animals on a lot of grain because they have little or no good pasture land. Whilst in others the cattle can be mainly on grass pasture augmented in winter by silage, and are a lot nearer being environmentally neutral. I do not know if as alleged, the UN report that led to the anti-cattle ideas, actually was based almost entirely on the former practices.

    I know the vegans particularly have  long been trying to persuade everyone to eat as they do, even before anyone worried about gaseous cows; but note I said "herbivores and omnivores", not specific creatures... such as ourselves. If the world went vegetarian, which is not very likely or feasible, that would only introduce new problems of its own; such as what crops do we grow and where, how do we fertilise the land, and what do we do with the very large areas of pasture very good for grazing but not for cultivation.

    Really it's all damned if we do, damned if we don't; because despite the campaigners and politicians wanting us to think otherwise, there are many difficult questions and problems but no quick and easy answers. And what answers there are, can only come from the professionals involved; not the campaigners and politicians of whom most appear to have very little scientific, engineering or agricultural knowledge.

    I am afraid, and this was my main message, that as the old saying goes, there is no such thing as a free lunch. Not even a vegan one.    
      January 12, 2020 6:45 PM MST

  • 43677
    Some of those could not be answered without research...which you said we can't cheat and look them up.
      January 12, 2020 5:41 PM MST

  • 3637
    The idea was to see how much you already know, not what you can look up!

    If you take part in a TV or radio quiz you have typically 10 seconds to answer a question without aid - this was the same but with much longer to think. 

    Though I had to verify a couple of details by text-book, I assembled it all from general knowledge, remembered school lessons, work experiences, and pondering current matters of public debate.
      January 12, 2020 6:10 PM MST

  • 46117
    This is why so many engineers have no idea why their wives are cheating on them.  

    This post was edited by WM BARR . =ABSOLUTE TRASH at January 12, 2020 5:41 PM MST
      January 12, 2020 5:16 PM MST

  • 1152
    Yes, but engineers don't necessarily care...

      January 12, 2020 6:12 PM MST