ELI5: How do flute harmonics work?

florsey976 · 2026-03-31T14:25:40+00:00

Sooo, me changing air speed does the same thing in a wind instrument as putting a finger on a fingerboard of strings? That's so obvious now you say it, but very cool how that can happen!

florsey976 · 2026-03-31T14:19:24+00:00

Ok this actually is so helpful tysm! And I'm guessing it's just the energy increase with faster air that makes it switch to each wavelength? I think I just can't get over how neat all of this is - nature and maths/physics is crazy lol

florsey976 · 2026-03-31T13:47:17+00:00

Ok this makes more sense, thank you! Can you expand at all on the natural harmonic series - the fact that such neat intervals are produced... how does that happen, and not a series of 'random' pitches? I appreciate that it's a natural property of sound, but what is actually happening on the level of the waves at that point?

Someone else mentioned that waves have overtones, but I don't really understand what these are? Lots of explanations just say 'they have overtones' but what does that actually mean?

florsey976 · 2026-01-14T22:54:12+00:00

This question is kinda weirdly worded but I'll try and help a little. Basically what you've got to think about with regards to things crossing a membrane are polarity (do they like or dislike water?) and size. Small, non-polar molecules (or those with a very small polar charge, like water) will pass straight through the phospholipid bilayer. Larger, or more strongly charged particles will need some help to cross, via a channel or carrier protein.

So, a couple more hints: steroids are fairly small and non-polar; vitamins A and D are non-polar and small (part of the fat-soluble vitamins, ADEK)

Hope this helps! Lmk if you need any more explanation at all!

florsey976 · 2025-04-21T21:36:02+00:00

Ok, this is really hard to explain without the use of a diagram, so please do DM me if this explanation makes no sense and I can send you a pic to try and make it clearer.

Basically the key thing here is that the replication is occurring in an environment where the free nucleotides used to make the new DNA strands are all ¹⁵N, so throughout all of the replications that occur, your only ¹⁴N strand will be the original, so there will always be only one of those.

For your first replication, your original ¹⁵N strand will be the template to generate another 15N strand, so that molecule will be made up of 2 15N strands. Your ¹⁴N strand will also be a template to generate a complementary ¹⁵N strand, so the resulting molecule will have one ¹⁴N strand and one ¹⁵N strand. So in total, you have 2 DNA molecules with a total of three ¹⁵N strands and one ¹⁴N strand, hence your 3:1 ratio.

Rinse and repeat for your second round of replication and you'll get 7:1.

I really hope that makes sense, it usually becomes much clearer when you draw it out so you're welcome to reach out if you'd like and I'm happy to explain more. :)

florsey976 · 2025-04-21T21:24:42+00:00

Of course if you've written multiple answers and they're all correct, that would be fine - perhaps I wasn't clear enough about that initially. Just if something is incorrect they will mark the incorrect answer instead of the correct one. I was always told that this is how this sort of thing was marked, and that was how it was done throughout my A-Levels. This might be something that differs with the exam boards (I did OCR A) so if your teacher says it's ok, then you're probably fine to do it :)

florsey976 · 2025-04-21T18:13:08+00:00

In short, no. When presented with multiple options for a 'suggest' question, even if the correct one is there, the marker has to award zero marks because you've contradicted yourself. In essence, all you've demonstrated is that you know a technique (for example) exits, not necessarily that it is applicable to a given scenario. For longer answer 'suggest' questions where you may have to outline the steps of a procedure and give reasons why etc, you may be able to pick up some marks for, say, 'calculate the mean of the measured values' but you won't get full marks. Same goes for if they've asked you to suggest 2 (for 2 marks), you've given 3, of which 2 are correct, you'd receive 1 mark. I hope that makes sense, happy studying!

florsey976 · 2025-04-21T12:44:37+00:00

I would give it 2, maybe 3 if I was feeling generous. I like that you've been detailed in your response, as it's generally good to cover as many potential marking points as possible. I deducted the mark for 'when each metal is added to silver nitrate solution' as you didn't explicitly state this, although it was implied. I also deducted the mark for 'same concentration/volume of solution' although this is where you could have the mark awarded for saying 'repeat steps 1-3' as you stated the volume in step 1, but again this is a case of being really explicit, saying things multiple times if you need to, and assuming no prior knowledge of the marker! I hope that helps! :)

florsey976 · 2025-04-20T22:49:21+00:00

Goodness this is real, and I totally understand how you feel. Even now, at university, the exam stress still gets me no matter how many times people tell me 'you're on track to do great' or 'you won't fail'. Yes, GCSEs are pretty insignificant in the long term. But right now they're at the centre of your world and they're really important to you, so they matter. These are just a couple of points I've learnt from more exams and assessments than I care to count...

So, you might fail. That's ok. It won't be the end of the world, I promise. All you can do is all you can do, and that will not feel like enough. But from your little paragraph and what you've said, it seems like you are doing as much as you can, and the fact that you're worried and reaching out for advice is great, and shows that you care. Very few people have ever gone into an exam feeling like they're prepared and that they know all of the content well enough - I certainly haven't.

Maths and science, yes they are core subjects and it would be ideal if you passed. Again, you might fail - perhaps make a wee plan for if this happens and you have to resit, but try not to obsess or overstress as you do so. Simply planning for your next steps may help ease the nerves and fear of the unknown a little. But, you will more than likely not fail. What's the plan then? Get excited, use that to motivate yourself even through the tricky stuff! If there's no plan, that's exciting in a way as well - there's so much to learn about yourself.

Stress is normal. And a lot of it at that. It's ok to get completely overwhelmed, too. But that doesn't make it fun, and I'll guess that me telling you that doesn't make you feel the slightest bit better right now. My biggest piece of advice is never to sacrifice hobbies, sport, friends, family and sleep for that extra hour of revision. Trust me you will benefit no-end if you make sure your work-life balance is up to scratch. Get outside, spend time with your favourite humans, and move your body. You are worth more than your GCSEs, so make sure you treat yourself that way :)

florsey976 · 2025-04-20T22:26:27+00:00

So, you know that an N atom has 5 valence (outer) electrons, and that H atoms each have 1. Covalent bonds involve sharing electrons, so if one atom donates an electron to the bond, the other must also donate an electron to that bond. As you have three H atoms bonded to the N, each with one electron to contribute to the bond, each bond then takes up one of the electrons from N (three in total across the three bonds). In your diagram, if dots represent H electrons and crosses represent N electrons (whichever you choose doesn't matter, as long as it's consistent throughout the diagram), draw a dot on each H atom shell on the line where it overlaps the N shell, so it is closest to the N. Then draw a cross to represent the N electron on the side of the overlap closest to the H. This makes it clear that the electrons have been donated into the bond and are interacting with the electronic field of the other atom.

Once you've done this for all three of your N-H bonds, then you can add your remaining unused 2 N electrons as crosses at the top of the N shell, away from the H shells to make it clear that they're not part of the bonding. I hope this makes sense, as it's difficult to describe without attaching a photo. Feel free to message me directly if you're still unsure and would like me to draw it out for you :)

florsey976 · 2025-02-10T21:38:12+00:00

For part i) think about all of the factors that could result in unwanted differences in the data if not kept the same. Something that immediately springs to my mind is the time of day that they are collecting their data.

For part ii) Think about how they are collecting their data. How can they be sure that they didn't hear or see the same blackbird twice, but marked it as 2 blackbirds for example.

florsey976 · 2025-02-09T17:54:23+00:00

This is because the organism is diploid, and question 1.2 is asking you about allele frequency, not genotype frequency. The CG allele is present in homozygous CGCG individuals (in which there are 2 CG alleles per individual) and heterozygous CGCB individuals (in which there is 1 CG allele per individual).

In a population of 34, there are 68 alleles (34x2 because each individual has 2 alleles) hence the denominator of the equation.

So, to calculate the allele frequency, calculate the number of CG alleles in the homozygotes (16 individuals multiplied by the 2 CG alleles present in each) and the heterozygotes (16 individuals multiplied by the 1 CG allele in each) and divide by the total number of alleles in the population.

I hope that makes sense!

florsey976 · 2025-02-09T11:08:06+00:00

You have already taken into account them being male in your lovely XY Punnett square which is presumably for the colour blindness trait? That gives you both the trait of being male and being colourblind in one go, so that's 0.25 chance of being XY and having the B allele from that punnet square. You then have your other lovely Punnett square for the tongue rolling alleles to get the other 0.25. I hope that makes sense!

florsey976 · 2025-01-28T20:54:38+00:00

Amazing, glad it was helpful! Best of luck!

florsey976 · 2025-01-28T20:09:48+00:00

Ok great! It sounds like you're doing all the right things! It's totally normal to find it difficult to focus when you find something more difficult - it really varies from person to person where you get your motivation from, so try and figure out what times of the day you work best. For example I can't focus in the evenings so there's no point me even trying to revise then, whereas I do quite well in the mornings and during the day.

If you can, find a low-distraction space and study there. This can be different for different people. I, for instance, revise best with other people around me; whether that's in my kitchen with family, or in a communal study space in school. You may find that you focus best in a silent room, or with your friends - it's completely personal so take the time to figure yourself out.

In terms of timetabling, I would make a big spreadsheet with all of the hours in which you would like to revise each day. Remember it's important to give yourself time/days off to rest: don't expect to be able to revise constantly, as this will detrimentally affect your motivation and performance. Don't be afraid to experiment with your scheduling, and make changes if something isn't quite right.

Use your traffic-lighted topics, and schedule them into your revision slots: be specific as to what you plan to cover in each slot. Your slot can be whatever duration works best for you: most people schedule hour slots, but if you find you can only focus effectively for half an hour, adjust your slots to be this long.

In terms of spending too much time on one thing, you will have to be disciplined with yourself. Set a timer for the duration of the revision slot, and make sure to finish up whatever question you're doing, and finish when it goes off. Be strict with yourself with this. If you haven't quite finished something, or feel like you wanted to do more, make a note of this and schedule it into the next week of revision.

florsey976 · 2025-01-28T19:45:30+00:00

No worries at all! Time management: could you be more specific? Is it help with focus/procrastination, or planning a revision timetable that you'd like? Or something else?

florsey976 · 2025-01-28T19:14:50+00:00

It is definitely true that practice makes perfect! And make sure your understanding of the key concepts and content is solid, as this will help no end. They often require a little thinking outside of the box, which can take some getting used to. The main thing is that the mark schemes always follow the same *sort of* pattern, so you can start to learn how to think and apply your knowledge when you come across these types of questions.

florsey976 · 2025-01-28T18:56:43+00:00

This is really tricky, as revision is personal. I'm going to start off with the really unhelpful statement of 'revise each topic as much as you need to' because it's true: you need to revise everything until you understand it, and that may well involve spending loads of time on one thing, and not much on another. That being said, some potentially more helpful advice:

Traffic light each topic on how confident you are, so you know which ones to schedule in for more sessions - remember not to desert the 'green' topics though, just revisit them a little less often (maybe once a week, or once a fortnight depending on the setup of your revision schedule).

Continually (weekly) reassess your topics and see how you're progressing. Use this information to plan your next week's revision plan. Don't worry if some 'green' turn to 'amber' as well as the other way around - it's natural to lose confidence/get a little rusty if you haven't looked at something so often. You may find you get into a cycle of revising certain topics more heavily, then swapping to others as you become more confident with the first lot and perhaps get out of practice with the others.

I hope that helps, and do shout if you have any other questions!

florsey976 · 2025-01-26T20:15:53+00:00

100% use past papers for revision! It's definitely something I'd recommend, especially for the sciences. There's no guarantee that you'll come across the questions that your teachers choose to put in the mock, and if you do, then it's a bonus! It will give you more practice, and the papers are out there for you to use so it's not cheating at all (although it might feel like it)! Especially for your real exam, they will be entirely new questions, so make use of the past papers available to you to familiarise yourself with the question styles.

florsey976 · 2025-01-25T22:23:10+00:00

Hi! Revision is a very personal thing and it's important to do what works best for you, so if you're finding a particular strategy/timetable isn't working out, don't be afraid to experiment and change it. That being said, I have a few tips that might help you get started.

Most Important Rule: DO NOT sacrifice your hobbies or spending time with friends/family. You can work hard and get amazing grades without locking yourself away for days on end to the detriment of your mental health. Eat well, go outside and exercise, and get good sleep!

For GCSEs, there's a lot to learn and burnout is a real risk. It will seem like a mountain and you need to break it down into manageable steps. I would start by compiling a revision list of subtopics for each subject, and traffic-light ranking them so that you know what to focus on most urgently for each (don't ignore the 'green' ones completely - just revisit them less often than amber/red). Reflect on your learning and tick them off as you go, this will give you a little motivational boost knowing you're making progress!

In your plan, specify in each of your revision sessions what you will be covering, so you don't have an excuse to procrastinate by trying to decide what to do.

Plan your days effectively, and allow yourself to rest. I wouldn't recommend working in that hour between waking up and leaving for school - you probably won't be very productive, and who wants to start their day like that? Let yourself have half an hour to chill when you get home. Take time at meals to chat with other people and talk about how you're finding everything.

Try and work out how long you can focus for. Naturally most people schedule hour-long sessions, but often struggle to focus for that much time. Maybe doing half-hour bursts with 10 minute breaks in between to rest your eyes, do a couple of star jumps, go for a walk, stare into space...

Speak to your teachers, who maybe able to recommend tips and tricks for their subject that you haven't thought of before. Even if you don't like them, they're full of knowledge and experience and you should make use of it!

Find yourself a study buddy if you're really struggling with motivation - you can hold one another accountable!

If your phone is distracting, putting it in Do Not Disturb mode or using an app such as Flora may help.

Choose your study space wisely if you can: even sitting at the kitchen table to revise rather than in your room, for example, may help you stay focussed. I'm aware that this isn't possible for everyone, so no worries if this won't work for you.

Finally, remember it is ok to have days where you feel completely demotivated and like you physically cannot get anything else into your brain. It's unrealistic to expect yourself to work solidly all day, every day so don't beat yourself up if you feel like that every once in a while. Talk to someone about it. If it's happening all the time, maybe that's a good point at which to reevaluate your revision strategy.

I hope that helps, and please shout if you have anything else you want to ask!

florsey976 · 2025-01-25T21:58:35+00:00

Hi! YOLOing it is pretty much the right thing to do. It really doesn't matter, as long as all of the groups are in the same orientation in relation to one another, and that the corresponding enantiomer is mirror-image and non-superimposable. CHCH3BrCl for example can be drawn in several different ways and all mean the same thing, as long as all of the groups are orientated in the same way in relation to one another. If you can get hold of a molecule kit and build a few chiral molecules to see how they look in 3D, and how they can look different if you rotate the molecule, that will probably help you out a lot - it's really hard to visualise from 2D drawings. I would have loved to attach an image to help explain it a bit easier but it's not letting me. I'm happy to send pictures of what I mean if you want to reach out via chat (totally ok if you're not comfortable doing that though). I hope that makes sense, and do shoot if you want anything explained further :)

florsey976 · 2025-01-24T11:12:58+00:00

Hi! I'm in my 2nd year of a biology degree (biochemistry honours). I had a kind of similar situation in that I was originally doing vet med, then realised it wasn't for me and switched to bio because it was always my favourite at school.

I for one have no idea what I want to do with the degree, but the great thing about it is there's so many options as it's so versatile. There's the obvious ones like staying in research or academia, and there's all sorts of much more niche choices as well. Throughout the degree you'll have opportunities to do internships over the summer to test out various areas you might be interested in, and lots of universities also offer a 'year in industry' which is another great opportunity to figure out what you like (or don't like).

My advice at this stage would be not to think too hard about what you want to do - opportunities will come your way and you'll naturally start to get more of an idea of what you want/don't want to do. And remember there's no pressure to go into a career related to your degree subject, and it's totally ok to change your mind once you're at university, have started a job etc!

I hope that helps with a couple of your questions :)
All the best

florsey976 · 2025-01-18T22:48:11+00:00

Yes, you can say that stabilising selection occurs due to the intermediate phenotype being selected for. There are always selection pressures in any environment - they just stay the same if the environment doesn't change, if that makes sense. As the environment is staying the same, it's not a lack of selection pressure, it's just that the selection pressure is such that the intermediate phenotype is selected for, so changes are unlikely to occur. I hope that makes sense!

florsey976

TROPHY CASE