Crushing cans from weight of one cup of water....Magdeburg Hemispheres without a pump..Bruce Yeany
ฝัง
- เผยแพร่เมื่อ 16 ม.ค. 2020
- Hydrostatics is the study of changing water pressure and it's relationship to water depth or column of water height in a pipe or tube In this video I'll demonstrate how water in a long thin tube can reduce pressure inside various soda bottles and can enough to crush them, actually it's atmospheric pressure that crushes them. Still, it's impressive when the reduction is due to the weight of just 2 cups of water. We'll also look at an alternative method for demonstrating the Magdeburg Hemispheres without using a vacuum pump, just a long thin plastic tube and 2 cups of water is all that's needed.
I am 48 years old and I want him as my science teacher.
I am 68 years old and I come with you :-)) ... from France! (I'm French!). Seriously: the way Bruce Yeany demonstrates a lot of physics phenomenon is great!
Oof 48 very close to death
Yes
I've been watching his videos whole day and I had the same thought when I saw the first one ...at 44
i am sure who ever is watching this video is want to be your students and they get encouraged to learn more about science 😍❤👍💪💯🔥
Physics of fluids and pressure is always incredible!
I agree, to get these results from such a small amount of water boogles my mind I have a couple more planned on the subject that I have to try.
This is simply black magic to me, an absolute failure of my public education. Thank you for going above and beyond to fill in the gaps for your students and your youtube audience.
(11:31) like a boss....
I thought that you'd retired Mr Yeany - couldn't they live without you?
they could but I miss it too much so I'm back in on occasion
One of the rare people who applies physics, beside just explaining, your videos are awesome
Dear sir my. We are from algeria and my son of 9 years is a fan of your experiments .i wish he comes like you one day good luck sir
Great visual representation of vacuum pressure caused by height differences! Keep it up Bruce!
One of the best channels out there. Have learned so much from your videos. Keep doing you, Bruce!
Man your awesome, wish there were more like you teaching in schools. You make learning fun and interesting and that’s the way school should be.
It's truly amazing to see your students so motivated. I wish I had any teachers as dedicated as Mr Yeany when I was a kid! Thank you for the great video lesson.
Your original video with Magdeburg hemispheres and you and the other guy pulling them apart was one of my favorites on this channel. It inspired me to get a set for my classroom even though fluid dynamics is not a standard part of my curriculum. I love the home made variations with the soda bottles!
i'm really glad i had good science teachers back at school, I only later realized that it's quite rare. happy for all these kids too!
Thank you for this! I have been designing a presentation for my kids' elementary school on air pressure. My goal is to help them "see" the invisible forces of the air all around them and hopefully start them towards an intuitive understanding of it. I am going to add this to the lineup of demonstrations I have planned. Your breaking wood with newspaper is one of my favorite unexpected results of an air pressure demonstration, one I am really looking forward to showing to the kids.
good to hear it helps, I have some more demonstrations for future videos on hydrodynamics and air pressure, check back in the future
No FANCY video. Direct to practice!!! Nice explanation!! Thats how have to be youtubers!! Thats about science!!
I've got to say, you put out some of coolest physic tests videos out there.
thanks, I do enjoy trying to make some of my own variations at times
Mr. Yeany always makes me want to be a better teacher! :-)
10 years as an engineer and this blew my mind.
Incredible how the force between each particle of water keeps the whole bottle of water from falling!
Outstanding, and completely satisfying. Your enthusiasm for science is contagious!
Top lecture, as always. Thanks Bruce
What awesome teacher.
I love this man. Thanks for teaching.
First class Bruce!
I forgot how powerful this is, THX for the vid reminding me!
What an awesome teacher
Really instructive. Thanks
You are a legend Bruce Yeany
One of your best!
Man, you deserve a lot more subscribers!!!
Woah ! Some people are meant to teach all their life ;-)
Love your videos! Practical experiments that teach you how to understand physics. Wish my teacher was like that at school (many years ago) but maby I have to do some of the things with my sons
This is excellent. Thank you!
How I wish I could say my science teacher in school was Bruce Yeany.
i wish i had you as a teacher.
that was way better than i thought it was going to be. every time
Good experiment thx you
You must be from Maryland
I haven’t heard “Wutter” since I left in 1985
💪🏼🇺🇸
Close enough, I grew around Philadelphia, I also hear it in New Jersey when I visit
The atmospheric press channel.
I straight up snorted reading this, well played
On holiday in the Canadian Rockies, we had fun watching (and hearing!) mostly-empty water bottles crumple as we drove down from various passes. Not so dramatic, but we were surprised that a few thousand feet had any effect at all.
amazing! thank you
Now I wanna get those hemispheres
once upon a time we failed to do more than one science experiments as our vacuum was broken,
Things would've been different if I had seen this 20 years ago :)
Thanks
I think that the noise we hear on the cans is probably a pinhole opening up on the aluminum, letting outside air bubble in. Especially considering that the vacuum is only 7 psi below atmospheric, the boiling point of water should be well above room temperature
thanks Eric, we are going to test this further and I'm in the process of collecting ideas and the materials for it. There are quite a few points that I didn't get to and want to try.
@@YeanyScience There was a really good video from practical engineering where he built a huge tube the height of a parking garage, and the weight of the water in that case did cause boiling at the top of the tube
I haven't seen that one but will look for it, I do like the one that shows the opposite of this where the instructor shatter a large glass container using the increase of pressure at the bottom of a long tube.
Respect that a beer can just happened to be available.
Now, lets try with a Submarine..
As a former science teacher here's something that's always bugged me. The 'Air has mass' balloon demonstration. I did this once and found I had to cheat the empty balloon. I weighed several balloons and they were all over the place; initially I attributed it to this. Then I started digging into it. Duh. How much mass of air is actually in a balloon? Not much. Well it was under pressure. Well not much pressure. Then it's water vapor from my lungs. Water vapor is lighter than the atmosphere. (Here I found what was actually behind those big arrows rising off the ocean in the water cycle diagrams). Then I thought, well what about water? So I filled water balloons and put them in a tank. One of them actually oscillated very slowly from the bottom of the glass aquarium to the top and back down. That was pretty cool. Buoyancy. In the water we notice it, but in the atmosphere we often don't think about it at all. So putting air in a balloon just displaces an almost exactly equal amount of air surrounding it. Net result: When you weigh a balloon, you are weighing the balloon, the air inside cancels out.
One Saturday all us secondary science teachers were called to Maya Angelou High School for more training in Next Generation Science, (the new voodoo, which is based on sound science. Behavioral science: any system of ritual more complicated than previously systems of ritual will appear to be 'more real.' ) They flew in and paid some 'expert' to inspire all of us 'lesser' uninspired science teachers. He started in on his 'model' Next Gen lessons, including, using a basketball to prove to students that air had mass. I started grumbling and got an elbow from a colleague. I am ashamed that I didn't shout out 'bullshit'. Basket balls to NBA specs have about 14 psi over atmosphere in them, so almost nothing, certainly a tiny fraction of 1 percent of the mass of a basketball.
I went home still thinking that I might have missed something. I took my Makita air compressor hung it from my 75 lb Weston spring scale, 28 pounds. I emptied the tank, 28 pounds (I made sure there was no water in the tank), I turned it on and brought the 2.5 gallon tank to 125 psi and the scale read 28 lbs (Maybe it was 32. It wasn't 29 or 30). Well, maybe there was some change but my spring scale wasn't sensitive enough to read it. (Of course air has mass, it's just difficult to measure it.... unless maybe you've taken more chemistry than me. I demonstrate that air has mass because you can blow on things and move them, so force is present.
I like your demonstrations, and how you never stop at just one. So air has mass. How would you do that? Thanks.
One way you can demonstrate that air has mass, is to weigh a soccer ball deflated to 1 atmosphere, and weigh the same soccer ball pumped up to 14.7 psi gauge pressure. From knowledge of atmospheric pressure, and treating the soccer ball as rigid, this means there needs to be twice as much mass of air inside the pressurized soccer ball. FIFA standards allow you to pump soccer balls to up to 15.6 psig, so 2 atmospheres of absolute pressure is within the specification. I originally thought to do this with a basketball, but they don't get pumped to as much pressure, so the air mass would only be about half as much.
When you weigh the ball empty, you will weigh the ball surface alone. The weight of the 1 atmosphere of original air will be nullified by the buoyancy force from the outside air. When you weigh the ball full, it should be about 6 grams heavier, due to the weight of the extra air. For comparison, an empty soccer ball is around 410 grams, so you'll need a kilogram scale with at least a 1 gram precision.
Always love your videos. Question: With the can that is right side up, you can see air-bubbles going through the tube. Is that water vapor from the water boiling due to the low pressure.
HI Mark, I don't think I'm up high enough for reduce the pressure that much, my guess is I was not careful enough when filling the tube or air leaks. I do want to show what you are asking and I have some additional equipment such as a clear pipe where I want to test this with, however the area that I planned to use is closed off for now due to Covid-19
Cool
This is amazing. What can I crush?
Why does water flow when you add tubing but not when it is in the bottle if the space for the surface tension is even smaller?
Is it because there is water inside the tube therefore increasing its weight or is it because something else?
If it was a very short tube would water still hold?
Is it because the meniscus is different?
I think it's because the water in the tube and due the the gravity is making enough force to pull the water down from the bottle
first: 4:51 Could this be considered as a primed siphon?
Second: when you flip a filled bottle of water, the water falls out, but air is also rushing in making the typical gulping sound. Why isn't the air travelling up the tube when you flip the can around like it does with a standard flipped bottle?
Third: when you use a container that doesn't deform (so strong enough to resist the atm pressure, will there be a "vaccuum space" arise above the water level? And if so, would we see the start of the water boining due to the decreased pressure?
if the hole is small enough surface tension will keep the air from entering, but when a tube is added to the opening, it's length makes a difference, the long column of water in a tube will not be able to stay in the tube, you may notice the I have to stick the bottom of it in a bucket of water, otherwise air will intermittently travel up through the tube and replace the water. I had planned on updating this video and had planned to show this as part of it but cannot currently use the school's facilities
Ahh I remember these time vortex experiments back when I was a lad on planet Gallifrey
Just curious, would this work with a glass container, such as a growler? Obviously not the ‘collapse’ but something other than just emptying contents? Thanks for the ‘teaching’ moment. Out of school for quite awhile, having a teacher like you wouldve made class much more enjoyable 🙃
Hi Bo, I am assembling a list of things to try and materials for it to test your's plus some other ideas on this. we'll see what happens
Mr yeany what would happen if you use bottle made of glass?
Next time use a train oil tank.
Btw, I love your video's
thanks, that would be awesome
Do a 5 gallon jug.. one of those clear blue ones.
If nothing else can be created from it, it can be an excellent can crusher. No need for a trash compacter or manual can crusher. lol
I would like to see if you go a couple floors higher if it can totally implode the cans and get them crushed down similar to what a 4 ton press can do.
Hi Mr Yeany,
I have been watching videos on youtube from a user called "learn for life" with videos demonstrating free energy water pumps, moving water up into fields tanks using a small diameter pipe inlet and larger outlet pipe downhill (he said 1:3 ratio). Using an air tight system "similar" to a siphon only a vacuum negative pressure inside the tanks instead. I know it wouldnt be 100% efficient but would the system work as demonstrated? The only similar example i have been able to find was this video and the flying drop siphon in ep1 of your siphon series, thats what led me here. Also if you could, possibly look at his video and explain the capped vertical air pipe on the outlet a certain distance and height from the tanks, almost like a ram or trompe?
I watched a few of the videos, several showed steps building it but not much in the way of explaining the process, however, in one of the titles they called it a siphon system, and one of the few efforts to describe it, had the person saying the outlet pipe is lower than the inlet pipe, which is required for a siphon to work, so to call this a pump I think is a bit misleading. To me a pump has the ability to lift water from a lower level to a higher level. My guess is that since they are using rigid piping, the tank is used as a way of filling the lines to get the siphon started.
@@YeanyScience its a sealed tank with a vacuum. Like the video you produced here with the crushing vessels, only it pulls water into a smaller pipe inlet than the outlet, the outlet goes downhill. And has some sort of pressure pipe half way down i think to catch air and build it as pressure like a ram pump, but i dont think its lower than the source, i imagine it like a piston in a combustion engine in continuous free fall, the vacuum never bleeds out. air cant get into the system to break the vacuum. But eventually the supply would clog or not keep up crushing the storage, I will exeperiment to see if its even possible, some people in comments say it is impossible. But imagine when they saw the first hydrofoil prototype.
Bruce did you come out of retirement and back teaching ? Or is these a old video . And by the way Happy 2020 !
this is a combination old and new, I go back in for doing some presentations plus substituting if they need it.
I had always wondered what my fish felt in their upside-down fish tank, it was only about two feet above the waters surface. I wanted to do a much more elaborate design, but now im afraid their little air bladders will expand as they go higher in it causing them to be too buoyant and then the float up as they cant control it and they pop.
I would think fish have a pretty good balance to the air bladders and can adjust them for quite a change in depth
why by adding the tube the liquid is coming out. is the tube diameter greater than than the bottle diameter.
Meeting you would be an honor.
I don't know about it being an honor but if you are ever near Hershey Pennsylvania you are welcome to stop by.
Wut if u had the tube go up into the sky. Can u exploded it instead?
air pressure is crazy
Well this wrecks my idea of building a vacuum airship. Seriously through, I've seen steam used to crush things, but never water draining out of a container, interesting twist.
both methods reduce the pressure inside the can and use the atmosphere to do the crushing
How can I use this to pull a vacuum in a chamber without filling the container with water and having no vacuum pump?
good question, if you want to pull a vacuum without a pump how about using a Venturi tube instead. I have plans to show this in a future video
9:29 So does this mean I could crush a moderately dented oil tanker that is parked 26 ft above me with nothing but a tube?
Would the containers still collapse in space?
out in the open in outer space, there is no atmosphere so they would not collapse
Why it is slower for the battles to crash in, using water vacuum in atmospheric pressure.
the speed is determined by how fast the air or water is removed, the water tube is very narrow so less of it drains at a time, a bigger water tube would be faster. The vac pump removes very quickly so it crushes very quickly
@@YeanyScience Thanks.
I was surprised the plastic hose didn't squash.
When the hose starts as a perfect circle, it is very difficult for hydrostatic stress to crush it. That is, stress that is uniformly distributed, and is purely normal stress with no shear, and no non-uniformness to the stress. When the air pushes on the tube uniformly on all sides, the tube won't deform beyond its own compressibility until it receives a disturbance that would turn it from a circle into an oval.
Now, if you intervene and force it into an oval cross section, then the hose will squash a lot easier
I didn't really get why the pressure decreases inside the bottle
What would happen if you used glass bottles? Besides a lawsuit
What will happen with glass bottles ?
I will be trying this in future video, as the bottle goes higher, the decrease in pressure will cause the water to bubble as it degasses, go higher still and the water should leave the container forming a vacuum in the bottle, if the bottle is not strong enough it implodes
how high should you go to make a glass bottle implode? yeah, I know it isn't as safe as a metal one, but...
the best you can do is reducing the pressure to a near vacuum which should be at about 40 feet, going any higher won't help. I think most bottles would withstand the pressure, wide flat sided bottles might break.
so it’s an iv drip?
You should redo this experiment with a 55 gallon drum
Now how high can u go before the difference in pressure stops increaseing
about 34 feet
Can I see the math
@@YeanyScience With the right conditions, you can get liquid water to be lower pressure than a pure vacuum, and take it higher than 34 feet [10 meters]. Trees grow taller than 10 meters all the time, and suck water up the xylem tubes, in a process you might not initially think would be possible. The highest we can get with simple manmade equipment is 10 meters, as maintaining the metastable state of a "super sucked liquid" that trees use to get water higher than that is very difficult to do.
@@radicalfanatic1309 The equation is: deltaP = -rho*g*deltaZ
we know P at Z=0 needs to equal 1 atmosphere, where the water is vented to the surrounding air. P1 at Z1 would be set to zero, for the water going as low as a perfect vacuum. Set Z0 = 0 to keep it simple.
P1 - P0 = -rho*g*(Z1 - Z0)
Solve for Z1:
Z1 = (P0 - P1)/(rho*g)
Set P0 = 101,325 Pa, P0 = 0, rho = 1000 kg/m^3, and g = 9.8 N/kg.
We get Z1 = 10.34 meters, or 33.9 ft.
the best cans- crushing- methode is using the hammer & the stump
This leads to a paradox of how trees can be taller than ten meters. Plenty of trees are a lot taller than ten meters, with the tallest living tree being 115 meters tall. But 10.2 meters is the theoretical limit for how high you can suck water up a tube before it boils, which is what trees need to do to get water from the root to the canopy. The answer is that the water is in a metastable state (call it a supersucked liquid) where it can carry a negative absolute pressure that is tensile, when it should be boiling, but it doesn't boil without the activation energy to start the process.
might be interesting to try this with heavier liquids, and try to show an increased crush
I am not sure it would crush more. It is my understanding that it is actually the air outisde the container crushing it. The liquid serves to prevent air pressure from crushing the container. There is a phenomenal Mythbusters where they crushed a full blown tanker car by reducing air pressure on the inside.
After reading the other replies I guess if the heavier liquid caused more of it to leave the container it could result in more of a crush
The lowest you can get the pressure inside the hemispheres to go, is a perfect vacuum. Using a denser liquid will just decrease the distance you have to climb the stairs to generate the perfect vacuum inside.
For water, you'll have to climb about 35 feet to generate a perfect vacuum inside the spheres.
For mercury, just lifting it 3 ft from the floor to the tabletop will generate a perfect vacuum.
5:15 boiling water at the room temperature due to the low pressure
Thought you retired?
some of the footage is from when I was teaching, some is newer, I still go in and do some presentations and substituting
not boiling inside the grey bottle...that noise is air leaking in from atmospheric pressure and travels through the water towards lower pressure cause everything takes the path of least resistance unless energy is applied...that gurgling noise of a gas going through water followed by an air only noise would not be their if the contraption was leak free...some of the water would remain in the tubing because of vacuum pressure...actually if the bottle was completely sealed its literally impossible for a of the water to come out of the tubing...which obviously happened because you can clearly here the difference in sound made from air only and a gas traveling through a liquid...I'm not saying that a very very tiny fraction of the gurgling noise was that of water boiling from being in reduced pressure environment. Its impossible to know for sure unless you know what the actual pressure was inside of the environment that the water is in...and check waters pressure/temp chart to determine if water can boil at the pressure its in and its temperature...you would hear the boiling inside all of the containers not just the 1...I'm sure that it was nothing more than a simple mistake since you said the right things in the video about the process of liquid at reduced pressure...we both know that you would need a very big and powerful vacuum pump to boil water in a vessel that is leaking...a version of the very first vacuum pump ever by man just wont cut it. (when there is a leak and air can get in but it will definitely do that it the correct conditions) it would be difficult for the actual vacuum pump to boil water when there is a leak like I heard of the gurgling noise and air rushing in...everyone is entitled to make mistakes because humans are not perfect at anything...I felt compelled to say something because this is being used as a teaching tool. if this was just a random video I would not even have made a comment. It is not teaching if what is said is incorrect...
thanks for taking the time to give your thoughts METO U, I think this demonstration can be a good starting point but by no means is the whole story. I agree that the sound may be some air leaking through the system. However, we have done other variations of decreasing the pressure inside a various containers and heard similar sounds where I know there was no air leak. Another possibility not mentioned is there would be some degassing of the gasses dissolved in the water, which will start to occur well before the decreased boiling point. I also didn't get into the temperature drop or that the next step after rapid evaporation would be the water freezing. The combination of degassing and boiling of water is easily demonstrated without a vacuum pump by students using a syringe filled halfway. Put your finger over the end and pull back on the plunger, the water boils very nicely for a few moments. Fortunately we are going to test the points you raised by exploring these concepts a bit further by going higher, using visible containers and pressure gauges. I do appreciate criticism of my work as it makes me strive to clarify my points in further works or in one case have removed a video and corrected them.
Bernoulli?
RATED: ⚗⚗⚗⚗⚗
9 out of 10 brain-e-acks liked this video
Water
Poor man's vacuum pump!
Now try with glass bottles ;)
I'm gonna do this the next time I drain down a hot water cylinder.
You ever find it funny that Atmospheric Pressure is 14.7 PSI and Gasoline's Stoichiometric Air Fuel Ratio is 14.7:1?
Do it with a glass bottle
In summary: don’t do this with glass bottles
Sounds like a great question to think and test... ;-)
I don't know if the sound is the sound of the water boiling. it sounds like it could just be tiny holes developing in the metal containers as they tear. I say this because alpha phoenix did a similar experement but had to go much higher to get the water to boil th-cam.com/video/hHNoHhbfFDQ/w-d-xo.html
If you were to do this with a glass bottle, would it just explode the glass? Lol
Mercury would increase vacuum in the tube
you're right, with mercury I wouldn't even need to go upstairs, however, few problems with mercury, not allowed in the school building due to it's toxic nature, extremely difficult to clean up if spilled, requires hazmat suits and expensive
It’s more fun to boil a little water in an aluminum can and then invert into water.
Please in Hindi india
Атмосфера здесь ни при чём . Заблуждению несколько сот лет. Планета Земля - открытая система, в ней не может создаться давление. Есть градиент плотности, обусловленный гравитацией, силой притяжения .
Сила, сминающая, сжимающая закрытую ёмкость - разрежение. Её стараются не замечать. Есть случаи при разрыве потока , в метровых и более водоводах плотин, вырывания кусков железобетона из тела водоводов. Это тоже атмосфера !?
You say the weight of the water causes the vacuum pressure, but then you also say that increasing the diameter size of the hose won't increase negative pressure but instead allows it to increase negative pressure faster. So saying "it is the weight of the water that causes the pressure" seems like a contradiction in words, because a bigger diameter hose = more water = more weight of water.
Can you explain why it looks like a contradiction in words? Are you saying static pressure weight, is that something different than weight of water? For example If i weigh on a scale the weight of the volume of water in a 1/2" diameter hose 20' long full of water, it will weigh less than the volume in a 1" diameter hose 20' long full of water, because there is more volume. More volume= more weight.
You keep saying "weight of water" so i keep wanting to think if i increase weight without increasing height, i can get more pressure. But you must be talking about something different, because 2 liters weigh more than 1 liter but yet, they both create the same amount of negative pressure over time, according to what you said. So i am thinking you must be talking about "the weight" of water meaning "the height" of water because the height determines static pressure?
I have 3 more videos planned on this question that you have asked in both comments, going higher increases the pressure and why the diameter doesn't make a difference to the pressure exerted. Also showing the increase in pressure as you swim underwater, The pressure is the same whether it is a tube of water or in a vast body of water like the ocean
@@YeanyScience Thank You. I was watching a video on a graduated cylinder experiment. But this cylinder experiment has 4 different size diameter cylinders all connected at the bottom with each other. To begin we fill the biggest cylinder and it equalizes out to the other 3 thru the connection in the bottoms. The weird thing that happens is it does "equalize" out but the smaller cylinders are at a higher level than the bigger ones.
Upon first glance it seems like the weight of the water in the bigger cylinder could be pushing the levels higher in the smaller ones, and i think this is in essence what is happening, but not without capillary action causing it first. First the capillary action happens in the smaller tubes, then the pressure is reduced in the tube, allowing the bigger pressure from below to raise it up.
Because if you think about it, who says the biggest tube in the experiment is indeed BIG? The biggest tube could still be small, but as long as it is bigger than the others it will push the smaller ones up farther level than it is at. What i am saying is if they were all the same size it wouldn't work, all cylinders can't raise at the same time. And i am also saying the "biggest" cylinder isn't raising higher and that is why, it is the biggest out of the 4, It has capillary action too because it too is in a cylinder yet it can't raise higher because the smaller cylinders are already reducing the pressure on those smaller cylinders(by capillary action) more than the bigger cylinder can reduce pressure by capillary action so the bigger one has the most pressure of the 4. So to me that can kinda confirm the bigger one is what raises the others, BUT not without the help of capillary action first. without that big one there, there would be no liquid at that level in the smaller tube to begin with.
So i was confused a little and not sure if it is capillary action or pressure, or what. I appreciate all your videos and response, thank you. I think i got it now, i think the way i explained the experiment i talked about here, is a good enough street description of what happened. I had trouble figuring out how the pressure rose the smaller cylinders especially when i needed to know even more basic fundamentals and that is where you came in . Thank You again.
I also want to find out what happens in your experiment, when we 33 ft and over in height, if we go higher anyway what effect will it have on your can? And also it is apparent that the ancients knew many things we(some of us) assumed they didn't, and know things we still don't know. Because look at the imperial numbering system 32 degrees is freezing, but at the same time 32ft high is in essence a type of freezing too, the boiling pressure height of a column of water. And look at free mason master is a 33 degree, 33 could be referring to above or below freezing depending on which freezing, if they are referring to height in ft, or temperature in F.
Hey brother, it's time to let that profile pic go.