The Tungsten Boat Riddle - Theory vs. Reality
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- čas přidán 29. 08. 2023
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What happens when you drop a heavy object off of a boat? Does the water level rise, lower or stay the same?
Here's an affiliate link to the Tungsten block I got on Amazon if anyone is interested: amzn.to/44uT4PI - Věda a technologie
I didn't get it at first, but I understand now. the key is dropping it from a boat rather than from the air. because the boat is displacing both the weight of the tungsten and itself, and once you drop the tungsten, the boat becomes more buoyant, and displaces less water.
thank you this helped me understand it better.
@@marshy25me too
This comment clarified the whole video. Thank you so much!
And to put it in more simplier terms in case you still don't understand well this is how my brain seen it and it made since to me before he explained it. So for me instead of seeing it as displacement of water I saw it as well a boat sinking or having alot of weight if you throw out the heavy cargo in the boat the lighter the boat becomes therefore making it float more but the proper term for it is buoyancy. And I guess all that is basically displacement of water so idk thats just how my toddler brain understood it 😂
So, it has nothing to do with the block of tungsten, it's just the object making the boat float higher than it was with the block, lowering the water level because there's less object volume in the water
Mad respect for designing such a complex and sophisticated timed release mechanism for this
The way I just visualise it is when you drop the cube the boat would float higher and your relative water level would fall and therefore you would displace less meaning the total water level would fall. ( in case anyone needs a different explanation.)
He should have just hired you to explain it in this video 🤦♂️
That is a great explanation, however, I still do not understand. I’m going to have to come back to this video and your comment at a later time with the hope that after my mind has had some rest, I’ll be able to comprehend the experiment.
Me quedé echa papas 🥔😅😂
If there's any concepts that confuse you and you'd like to see me do a real-life demo on, let me know here in the comments!
Can you explain about the magnetic filed by a circular conductor while passing electricity because it has poles circular so all the points of circle are poles?
You should have also included the explanation about how it's due to the boat that causes the water to lower, it's not actually based around the tungsten cube
Yes please, my brain wants to say "well actually, less Styrofoam is in the container, causing it to look like less"
I just have to say that I LOVE approach to teaching people to be less credulous, and that the educational value of what you're creating simply cannot be overstated.
I think that one very valuable thing you could add is instead of viewers merely finishing the video and simply knowing 𝘵𝘩𝘢𝘵 something is true or fake, providing them the facts, clues, and logical connections that could have used to 𝙪𝙣𝙙𝙚𝙧𝙨𝙩𝙖𝙣𝙙 why it's true or fake. For instance, for the recent "Sunscreen blocking IR light", I didn't 𝘬𝘯𝘰𝘸 it was fake, I 𝙪𝙣𝙙𝙚𝙧𝙨𝙩𝙤𝙤𝙙 that it was.
1. Infra means "under", so "infrared" is under red, meaning it's lower wavelength
2. Ultra means "over" or "more", so "ultraviolet" has a higher wavelength.
3. X Rays and Gamma Rays are very short wavelength, while radio is long.
4. Ultraviolet must be the dangerous one, not IR, sunscreen doesn't block IR.
Or with more specific knowledge:
1. IR is generally between a millimeter and a micrometer and is less powerful than visible light
2. UV is between 100-400 nanometers and is more powerful than visible light.
3. If IR was harmful, then visible light would be as well
4. More powerful individual photons do more damage
5. Because IR is closer to the scale of cells and larger, it can't affect DNA. Its effect must be on entire cells.
6. UV is closer to the scale of proteins and molecules, so it can affect parts of a cell, and when parts of a cell break, you can get cancer.
7. Sunscreen prevents cancer.
Or with even more different knowledge:
1. 50% of solar radiation at sea level is IR, 3% is UV, and sunscreen doesn't make the sun feel half as hot.
And the same thing goes for the truths, what were the facts we might know that would let us 𝙪𝙣𝙙𝙚𝙧𝙨𝙩𝙖𝙣𝙙 what is happening, rather than just knowing that it's true.
For the Ice + Salt + water + water bottles, that fact could be knowing that sodium chloride salt lowers the freezing point of water, allowing the salt water mixed with the ice to become colder than 0C without freezing even in the presence of nucleation sites, and allowing the pure water in the bottles to become super cooled until it encounters existing ice which acts as a nucleation site to allow the creation of the slush.
But again, thank you so much for what you're doing to encourage more incredulity.
How mirrors work😂
I would like to not be dropped off a boat, please.
I completely ignored the fact that we were dropping this thing from a boat
Yeah it literally wasnt until the very end of the video when I realised that his original premise was dropping it from a boat and not just dropping a cube of tungsten into water. I was sitting there the whole time saying no... it definately will raise the water... and then that little oversight of mine dawned on me!
This question gets much harder if the block of tungsten is connected to the boat by a chain
not really it would just momentarily be the same as the video and then it would displace about the same amount as when on the boat then its just a matter of how much more or less then before is displaced depending on what kind of chain
@@anonymoususer8517wouldnt it displace more watee than in the boat, because it displaces some water by its volume but also pulls the boat down and makes that displace wayer
@@mcmonkey26It wouldn’t, because the volume that the cube displaces is also counted towards the total volume displaced by the boat and the cube combined, a way of seeing it is: if you weigh the cube and the boat in grams, it will be the milliliters of water that it displaces, no matter the configuration (in real life it’ll displace a little bit more not because te configuration, but because the weight of the chain)
If you don't get it, the density of tungsten first pulls the Styrofoam down causing it and the Styrofoam to displace a lot of water. When the tungsten is dropped it sinks down and the Styrofoam goes up. Since the volume of Styrofoam is larger it will "undisplace"(no longer displace so much water)
When he put it inside water with a rope, the rope displaces less water than the tungsten so it won't work
Thank you, I didn’t understand until I read your comment ❤
This was a mock exam MCQ question in my IGCSE papers. My teacher deliberately gave it, and everyone got it wrong in the exam. Its been 5 years since that, I am almost done with my degree in Physics. But stuff like this always kept me wondering. Thanks for the explanation, please keep uploading more videos.
Put another way, when it floats, it needs to be lifted ONLY by water. When it's on the bottom, its being held up by the ground, and so much less water needs to be displaced to hold it up.
good point, but careful you don’t confuse the displacement of the boat and the displacement of the cube. in this example it can easily be mistaken that the cube is somehow lessening it’s displacement.
Bros better than my science teacher💀
That was an awesome demonstration, thanks a lot !
0:18 let's not talk abt the stickman that was violently murdered and disolved in acid
This guy teaches me more than my science teacher
Oh that makes so much sense now! The water level lowers because once the cube is released, it’s no longer pulling the whole styrofoam volume down with it
A very clear and informative demonstration
I think it would have helped to mention that the reason it lowers the see level is because it displaces the water while on the boat.
That is actually what I missed the first time.
Yeah the phrasing definitely could have been improved, but this is the standard way it gets asked as an interview question. I also should have shown the boat rising in the first clip.
Lot of respect for people who study math and sciences. I don't even know what half of this stuff means lol 😂
The most complicated word he said was displacement if you can’t understand that then you need better education
You can learn; it gets really fun when nuclear fusion and fission get involved, for obvious reasons; the information can be found over the internet
The styrofoam felt like April fools
I was thinking I didn't understand the statement, I was like "anything that you drop in water will displace its submerged volume", then you repeated "from a boat" and then I remembered that this is how ballast works. Nice video 😄
Every word the details are so important in that first one.
Excellent video! I now understand: on the boat, with the tungsten, the average density of the boat is still less than that of water, which causes all of its weight to equal extra upthrust from the water on the boat, which is equal to the weight of the water displaced (which is larger as a result). Throwing the tungsten cube off the boat causes it to sink since its average density is higher than that of the water, so a smaller volume of water is displaced since upthrust is now less than weight and the density:volume ratio of the cube is much higher than the density:volume ratio of the cube + boat.
I really love your vids and enjoy physics as a hobby myself!
I was so prepared for this to be a "nothing changes" in the 2 truths and trash video. (because when we talk about floating ice cubes melting into water, the water level won't change). However, I spent a second to check if I was right because I thought of the extreme case (consider a very heavy and very small object in a massive boat, when the object is in the boat, it really lowers the boat, displacing a lot of water, but when you put it in the water, the object only displaces it's own volume. (so if it's very dense, it won't displace very much water relatively to the amount if pushes the boat down))
In this thought experiment I stumbled exactly into this result.
If the boat were supporting a plastic block that were equal in density to water, then the water level would remain the same when you release the block.
@@carultchnot quite, and to explain why, consider what the boat has in it after the plastic block is removed, in this case, it'll just have air on it, which is lighter than water (the plastic). This means it will necessarily be lighter after losing the plastic block, and thus will rise afterwards.
A way to explain this, is consider if we had the boat sitting on the water - empty. Then we slowly added water until it was full. As it fills with water you will see it start to sink, and with most boats, it'll completely submerge and then keep going. (This is why boats always have tools to remove water, and many sailors really don't like a lot of water inside the boat.)
@@jffrysith4365 Ok, I'll rephrase my point.
If the boat were supporting a plastic block, hung from below its hull (the way the tungsten block was in this video), that equaled the density of water, then releasing the plastic block would yield no net change in the water level.
The plastic block would also just hover in place and neither sink nor float.
@@carultch yes, that would be true, because the boat won't be supporting the cube (as it will 'float' mixed in the water, so the rope will be slack (assuming the ropes mass is negligible lol)
Sorry, I can't remember exactly how the experiment went on this video as I saw it a while ago.
@@carultchOh, I see where this point was coming from from my original comment. And no this is not an analogue if the cube is hanging from the boat.
To explain why, first we must consider where the mass of an ice-cube is being stored. In this case, the entire mass is stored in the boat.
Consider now, this experiment. In this experiment, the mass is stored in two separate chunks. One part is stored in the boat, and the other in the plastic cube.
Now consider the plastic cube, for it to pull down on the boat, it must be the case that the net force on the cube must be negative (down) This means the force of gravity is greater than the force of buoyancy. This happens when the weight of the item is greater than the mass of that around it. (in this case, the mass of the water.)
Now since the plastic is in the water, the plastic will experience no net force from gravity / buoyancy as they will be equal.
Consider now if the plastic was out of the water, say on a stick above the boat. In this case, it will be heavier than the air around it, so it will apply a force down on the boat (this makes sense because it will try to fall on the boat if we used string instead of a stick.)
This means these both are different because the object is surrounded by a different medium. In the ice-cubes case, since the ice is all attached to the 'boat', this is similar to the latter case. To explain why, the reason the plastic doesn't pull on the boat is because the plastic is able to float on it's own seperately from the boat, but the ice cube can't do that, if one part floats the other part floats too.
Thanks for the explanation, you visualized it really well
Ayyy I JUST saw this on the Science Asylum channel! Love seeing even more physical demonstrations of science theory :)
I thought it would stay the same at first but yeah. It makes perfect sense when you think about the difference of volume and weight and how those affect buoyancy.
That's why massive ships can float. They can displace more water than they weigh
This only works if the objects dropped are denser than the material of the boat
Water level lowers.
3 things to look up to verify. The density of tungsten, water, and the formula for buoyancy.
Tungsten: 19.3g/cm3
Water: 1g/cm3
Buoyancy = Density of fluid * volume of displaced liquid * gravitational acceleration
(Also, know that the buoyant force upwards is equal to the "weight" of the displaced fluid)
The main thing to consider is bouncy. Since the block of tungsten starts on the boat there is a buoyant force acting on the block of tungsten. The entire boat is floating, and the mass of the tungsten is included with the mass of the boat.
We can ignore gravitational acceleration in the formula for buoyancy and the "weight" of the boat. So, the mass of the boat including tungsten equals a certain volume of displaced water.
When the tungsten is taken out of the boat, the mass of the boat is decreased, which causes the volume of displaced water to decrease as well.
Let's consider how much that volume would decrease by. Say we have a cube 1cm3, the mass would be 19.3g. When this mass is removed, that will allow for 19.3g of water to no longer be displaced. Since water is 1g/cm3 that would mean 19.3 cm3 of water is no longer displaced.
Once the block enters the water it will sink, since tungsten is denser than water. Before we were working with a 1cm3 cube of tungsten, so that will displace 1cm3 of water when it sinks.
We started with displacing 19.3cm3 of water for this 1cm3 cube of tungsten to displacing 1cm3 of water for the tungsten. A higher volume of displaced fluid in a fixed container would indicate a higher water level. Having less volume displaced would indicate that the water level is lowering.
The exact size of our tungsten cube really doesn't matter. A cube of twice the size will displace twice the water, half the size half the water. The important part is that tungsten is denser than water, and quite a lot so.
Another good way I've learnt/heard is to take the extreme. Imagine a boat about the size of a canoe, and imagine a very spectacularly dense material which say has the volume of a pea and the mass of about 35kgs. (this is impossible but still)
When the pea is in the boat, the boat goes down, and water rises (bouyancy), so the level is higher. But, if i drop the little pea into the water, suddenly the boat is no longer "heavy" and displaces much little water, and the pea barely takes up any volume
This is of course highly _not_ rigorous, but is good to "predict" outcomes. This method's esp useful for me when it comes to code. Imagine the worst thing that can be thrown at the thing you are making. What is the worst possible outcome, and a) can the effects be reduced or b) is it worth fixing in the first place.If b), exaggerate less :v
0:17 bro really showed us some breaking bad footage💀
the key is that the cube is MUCH more dense than water. and as the density of the material goes up, it still displace the same volume.
So by having a flower, you distribute the density across larger volume until it reaches equilibrium.
When you detach the weight, all that density is again concentrated to that small object.
Thinking about it for a moment, yes it makes perfect sense. The boat is now displacing less water because it now has less mass to displace, making the water level lower slightly.
It makes so much sense now🤯
yo jadropping science is the best tbh
appreciate you!
@@JaDroppingScience same for you
Thank you my good sir for being the first time I used that feature on the CZcams short
This is incredibly simple and complex at the same time
this is so awesome! I never even considered that!!!
So basically the tungsten cube weighs down the styrofoam to disperse the water and when released, the styrofoam floats up, un-dispersing the water
the way i see it is
the tungsten weighs the boat down, allowing it to displace more water then it would otherwise, thus raising the water more when its on the boat.
Once he said that it actually got lower I understood immediately. Really cool concept that’s very intuitive.
The first one seemed ao simple and correct that i went for it
it lowers displacment because the syrafoam was also not doing any displacing anymore
This makes logical sense, but aren't there other factors to take into account for that we would see in a real boat. Understandable you are trying to simplify this to exaggerate the effect, but if we have a wide enough boat would this just cancel out? like the tinfoil penny boat. Make more of a canoe shape and itll hold like nothing, make more of a barge and you can hold a lot more. It should stand to reason, although I may be wrong, that the pennies are displacing the barge less than the canoe (Im not sure why this is, but my guess would be that it may be due to surface tension of the water or something of the sort?), which would mean that the change in displacement of the water will be far less. Could we reach a point in which the boat is displacing less water than the cube can, therefore making it so that the water level will rise when the cube drops? Or maybe just reach a point in which the displacement doesnt change?
it doesnt matter how wide the boat is, it will still take 19 cubes of water to hold up the tungsten, so when you throw it off the boat the water level will always drop by 18 cubes
This is exactly what I initially thought, that the removed weight on the boat more than counteracts the displacement of the cube but I still don't get it honestly
After a lot of mental gymnastics, it makes sense, but my brain still hates it
Oh, I see, the key word in the statement is “boat” because if it was dropped from land, in would only rise, but when it’s dropped from a boat, it causes the boat to weigh less, thus, displacing less water
Depends how big the boat is, and on how buoyant the boat already is. It only works if the boat is at the minimum possible bouyancy and thus minimum possible size. It's thouroughly ridiculous.
This is fascinating
I had the wrong answer for the right reason! I assumed it would be EQUAL because the weight of the cube was already moving the boat down, but neglected how you transfer it's displacement from Weight to Volume by simply _chucking_ it off the boat! That is Fascinating!
I was close. I thought it would stay the same because of these same reasons, except I thought the boat rising would only equalize it out
My brain exploded for a minute. This man just open the new gateway for me of knowledge😅
The key is that it's thrown from a boat if it were from the coast it would obviously rise
Thanks, man, now I'll definitely become a star student in science
EDIT: they're calling me a nerd now
I didnt consider that he said its from a boat, so basically the tungsten is holding the boat down, with it gone the boat can float up and decrease water level, i feel like this is still conditional, you could probably see the water level rise is the mass was slightly denser than water and the boat was slightly less dense
This video cured my mortality.
yeah the key thing is that lower of water is relative to the person on the boat. From an intertial frame the boat rises (needs to displace less volume of water as total weight is less) and the water level doesnt change much (due to tungsten sinking to the bottom and displacing its volume of water)
I wasnt even thinking about the boast part in the beginning the entire time😅
So essentially the weight of the cube is pulling the larger volume deeper, thus displacing more water. So when you drop the heavy material, even though that small material displaces water, it replaces the water as the boat now rises out more from the water
> What happens when you drop Tungsten off a boat?
It gets wet?
lol I'm terrible at thumbnails and titles so I would love any suggestions if people have them
My large dense object was actually like absolutely massive and my boat was really wacky and super tall so checkmate. Or something.
That is very interesting
The explanation with the blocks is a lot more confusing than it needs to be, but the demos are great
I almost thought this was a joke video. You need to include the detail about the boat directly
I almost want to call that cheating😂
"Off of a boat" is doing alot of the lifting in that sentence isnt it?
Oh! Density. Forgot that 😂
Where did you get that cube of tungsten? I love elemental metals 😊
While in the boat, the weight of the tungsten displaces water based on the volume of the boat.
When dropped in the water, the weight of the tungsten displaces water based on the volume of the block.
Imagine you had a hyper-dense material the same size as that tungsten block. Because it’s so heavy, it would push the boat pretty deep into the water. That change in depth between when you’re holding the block and when you drop it is pretty large, and that means a lot of volume had been pushed under water by the block’s weight (“air” in the boat that is below water level now, but not after you drop the block because the boat rises up).
But when you drop the block in the water, now the only displacement is based on the volume of the block itself, which is comparably very small next to the volume it caused the boat to displace.
So more water is displaced while you’re holding the block in the boat, meaning the water level is higher before you drop the block.
While in the boat, the weight of tungsten displaces water based on the weight of the tungsten. If the tungsten weighs one pound then it will displace one pound of water.
@@barneylaurance1865 That’s not how that works.
Excellent Video, I now have a even worse understanding then I did before!
This is interesting, but it's just a trick question that could've been explained in seconds rather that needing it's own video
Damn, never thought to think of it as if the boat wasn’t negligible.
Got asked this question in a job interview once.
I still don't understand.. if you maintain the level of styrofoam before and after dropping tungsten then it should stay the same right? So is it ok if I just assume that you just decreased the weight of the boat?
it's impossible to maintain the level of the boat because the weight of the cube causes it to displace more, thats the whole point
Man thats insane o_O
So what you’re saying is that we have to drop a whole bunch of tungsten off boats to stop the rising sea level
no because we would probably create specialised boats to do this so taking resources of land into the water will actually speed up the rising sea level if you want me to explain more just ask
fuck i sound like a nerd
The part when the body was put in the acid or something caught me off guard
Fun fact, surface of the ocean (water level) is similar to the ground level of said ocen, so if you drop dense object (that will be big enough to make visible for human eyes change) it will change the level of the surface. What you explained in the video is how floting objects interact with water when they have different weight put on them (I don't know the name of the science term in English). To summarize the amount of the water stays the same, so when you put objects in it, the level of the water will rise. Similar to how you rise the level of the water when you go in the bathtub (even if your body would float in the bigger pool of water). Please don't spread misinformation 🙏🙏🙏
Damn logically the boat was heavy with the object and therefore if the object is in water or not even in water,the boat's overall weight is reduce,making it float a little bit higher
0:19 WHAT was that illustration
😂
This is how we stop water levels rising
Is that true also for boats, that are like v shaped at the bottom? I feel like this is only true for a floating ground. But I can be wrong here.
the water lowers because the boat has less mass, see how when the cube fell the boat rises? its the weight of the boat that lowers and therefore less water is displaced
Yeah the only problem with the video and the question being different is the fact that the question asked “if you drop it INTO water” and not “if you release it while already in the water”
Sand has left the chat.
Just compare it’s weight/density ratio to the air inside the boat that pushes the water away
The water level still lowers, the boat just gets lighter.
so if you drop tungsten into water the water goes up but if you drop tungstun from a boat then water will go down
I really thought I had it on that last round. I should've paid more attention in... school.
Pay attention in school, kids, or you won't know the difference between truths and trash!
@@9nikolaiThis is fact.
@@chilledburrito False. You can learn to see the difference between truths and trash even if you don't pay attention in school. In fact, there is much school doesn't teach you that is important in day-to-day life, so not only can you learn after school, but you should and must.
@@9nikolai1999 Toyota Camry.
The cube can’t start under the water
we've found the solution to rising sea levels. Just drop a few big tungsten cubes off boats! genius!
Common sense to me, knew the answer in advance
Ohhh, so its because you drop it off a boat
"If you drop large dense objects in a pool of water, the level will rise slighty" This is TRUE. No matter boats and sht. You are putting extra volumen on a closed system, the system will increase in volumen. Period
Nice, i thought about it for a minute and decided it Lowers, good i was right
What.
How.
Just how!?
i dont get it
the water level lowered becuse the styrofoam rised to top so it wasnt displacing water anymore
So are you getting it or not?
The point that this video makes is only hard to understand because you don't make it clear that you were factoring the boat into the question.
Like, yes it will temporarily lower to what it was when the tungsten was still inside the boat. But once you're back ashore, the water level will still be higher than what it was before you went out and dropped a block of tungsten in it.
Im using this as a science fair project gehehe
That's a very long video just to say "pay attention, it's dropped *from a boat* " which I guess is what the majority of people including myself just glossed over like "you're putting stuff into water, off course the level is rising, duh". Now stay with me, many people would assume the "level of water" is the level of the lake in general, not the level right after the boat dropped its stuff.
That could have been an interesting question but really most people just missed the point.
That sure does look like an annoying skinny vase.