Sciencemadness Discussion Board

Periodic Table Display

MrHomeScientist - 5-2-2013 at 12:19

Very recently I finally completed a pretty massive project that I thought I'd share with you all: a large periodic table display for my element collection! I designed and built this myself, since my element collection has grown large enough where I think it deserves a nice display unit.

Broad overview: it is a large freestanding display unit with individual acrylic shelves for all 118 elements (plus two placeholders for the lanthanide and actinide series'), with the shelves backlit by LED strips. The display is able to be broken down into four pieces, to allow for easy transport. The LEDs are controllable via an Arduino "master controller" and several LED driver boards mounted to the back, allowing for some really neat effects. In the future, I plan to write a tablet app that can control the display via a periodic table GUI. That will enable things like Quiz mode, where multiple choice questions can be asked, the answers lit up on the board, and the correct one flashing (or something similar).

I put together a video summarizing the build and showing it in action:

<iframe sandbox width="560" height="315" src="http://www.youtube.com/embed/LSY_DKQv4g0" frameborder="0" allowfullscreen></iframe>

I go into much more detail on my blog, in a series of posts starting with the introduction: http://thehomescientist.blogspot.com/2013/02/the-element-dis...

I won't attempt to replicate all that info here, but here are a few fun facts about the display:

- Design time: 3 months
- Construction time: ~1 year (working during my free time)
- Dimensions: 48" tall x 65" wide (about 4 ft x 5.5 ft)
- Number of holes drilled: 361
- Cost: ~$1000 (not including the actual elements, or all the prototyping materials I went through)
- Current collection: 51 pure elements, 10 elements represented by radioactive decay products (U ore), and 2 representative compounds (Teflon and AmO2)


Soon I'll be going through my whole collection in another set of videos as well, so stay tuned for that!

Hexavalent - 5-2-2013 at 12:28

That looks incredible! Congratulations on such a brilliant looking display that shows the elements at their best.

Well done! :D

Nickbb - 5-2-2013 at 12:32

I'd love to see this in person! You did it great job on it, can you post a video showing all the elements you have? I'd like to see that.

neptunium - 12-9-2014 at 10:00

got mine outta wood just made !

periodic table.JPG - 1.2MB
the lanthanides and actinides section is just behind it where Gd sits(in the middle)

Amos - 12-9-2014 at 18:18

Y'know, Sciencemadness should really do some kind of awards thingy for the people on this site that really stand out. Because this is just stellar. Awesome display man, and thanks for representing home chemistry in such a positive light(no pun intended) when you take it places. Can't wait to see it with all the elements, someday.

elementcollector1 - 12-9-2014 at 18:40

I wish it had different colors for each element - corresponding to their flame color, or in the case of the transition metals the most common salt color, or something like that.
What's the code for the Arduino, incidentally? I've had quite a bit of experience writing for Arduinos.

MrHomeScientist - 15-9-2014 at 07:01

Thanks very much, No Tears Only Dreams Now! I've taken it to several events now and it's been a pretty big hit. I think people really like seeing actual physical samples, like I do. Most people ask about Uranium, then freak out when I hand them a sample :)

EC1, that would definitely be cool. 6 colors was about the most I could find for single-color LED strips, though. Going to RGB LEDs would have added another layer of complexity to the wiring and code, and quite a bit more expense. For the Arduino, I'll direct you to my friend that helped put that side of the project together for me: http://www.billporter.info/2013/02/02/the-elemental-illumina...
If you don't feel like reading through all that, here's the direct link to the source code on github: https://github.com/madsci1016/TheElementalIlluminator

elementcollector1 - 15-9-2014 at 09:06

Not really - a 30 ft. strip cost around $15 on Amazon, last I checked. The coding isn't too hard, either - 3 logic-level transistors and PWM outputs that vary based on the color you're going for, and you have every color of the rainbow.

Looking at this, this seems like an awful lot of circuitry and work - but the end result is amazing! I don't think I could top 'music mode' for my collection. :P

MrHomeScientist - 15-9-2014 at 10:18

Yeah as he says in his blog post he pretty much threw it together quick and dirty because he was ramping up preparations for his wedding. So understandably a bit distracted. I'd never worked with hardware level coding before this, so it was very interesting for me to have a 1kb size limitation!

Pyro - 16-9-2014 at 15:56

you might want to brush DCM on the edges of the Plexiglas to make it completely transparent.
other than that, it's perfect!

neptunium - 13-10-2014 at 07:18



new resized.jpg - 1MB

Texium - 13-10-2014 at 07:20

Nice neptunium, it looks great!
Also... do you have plutonium? :o

Edit: Never mind, I just realized that your table is arranged slightly differently than mine, which would make that americium, right?

[Edited on 10-13-2014 by zts16]

neptunium - 13-10-2014 at 07:31

correct! i dont think any of us could get even micro gram quantity of element 94....
Lanthanum and Actinium are on the main frame leaving only 14 compartments for the lanthanides and actinides .


mine is not as fancy but i like it nonetheless!



[Edited on 13-10-2014 by neptunium]

careysub - 13-10-2014 at 11:41

Quote: Originally posted by neptunium  
correct! i dont think any of us could get even micro gram quantity of element 94....

[Edited on 13-10-2014 by neptunium]


That is correct - the only element heavier than uranium allowed for private possession without a specific license is americium.

You can however get neptunium if you buy one of these:
http://www.ebay.com/itm/PYROTRONICS-F5B-Ionization-Smoke-Det...

a Pyrotronics F5 smoke detector made in the early 1970s. These contained a whopping 80 microcuries (20 micrograms) of americium, and since they are now 40 years old 10% of that has decayed into neptunium. For $120 you can get 2 micrograms of neptunium.

phlogiston - 13-10-2014 at 12:18

There is this Russian smoke detector that supposedly contains as much as 0.5 mg of said element.

http://www.periodictable.ru/094Pu/Pu_en.html

I'd be difficult to procure anywhere outside of Russia and illegal to possess in most places though.

neptunium - 13-10-2014 at 15:02

0.5 mg of Pu239 !!!!! wow!!!!!

careysub - 13-10-2014 at 15:53

Not an "unusual element" but I favor adding all three isotopes of hydrogen to an element display, since there are few elements with multiple isotopes that you can get in pure form, and none that are demonstrably different in their behavior.

Vials of light water and heavy water can be displayed with a peice of polystyrene in each (sinks in light water, floats in heavy water) and you can us a tritium gas glow vial for nice tritium display.

There is a guy in Europe selling tritium glow spheres that contain a whopping 10 curies of tritium. This is one milligram, and is about 1/5000 of the amount used in modern thermonuclear weapons.

http://www.cpfmarketplace.com/mp/showthread.php?270326-B-rt-...

The CandePowerForumMarketplace website is a PITA to get a usable active account on (moderator approval required to register, three posts are required before full activation, which also require moderator approval...) so you could try emailing the vendor directly if interested:
"Bart" pixpimp at gee mail

It appears that the EU is cracking down on tritium sales and sources this large aren't being made anymore.

Oscilllator - 13-10-2014 at 16:15

Why would the EU be cracking down on tritium sales? Do they think people are going to extract the tritium to convert the fission bomb they already have into a fusion bomb??

careysub - 13-10-2014 at 16:29

Quote: Originally posted by Oscilllator  
Why would the EU be cracking down on tritium sales? Do they think people are going to extract the tritium to convert the fission bomb they already have into a fusion bomb??


Just the usual consumer safety considerations.

10 curies is a lethal dose of tritium if absorbed as tritiated water, and no fluid flushing is used for treatment.

The US does not permit the sale of tritium gas tubes at all, I believe. All the sources of these are European or Israeli.

diddi - 13-10-2014 at 17:01

great display MrHomeScientist. more inspiration for me to get of my behind and do something! I wish I had a spare year...

a couple of thoughts:
I am trialling SMD5050 rgb LEDs for lighting. they can be controlled by PIC, laptop, ardruino etc. I bought 100 of em for a couple of $

are your sample tubes under argon?

MrHomeScientist - 15-10-2014 at 11:39

Thanks! No, nothing is under argon. However, careysub just recently turned me on to "bloxygen" - a commercial product that's just an aerosol can of pressurized high purity argon! I bought a few and used some to seal some lithium pellets in a media bottle. I've had it there for several weeks with no visible tarnishing at all (well, no more tarnished than it was to begin with). I think I'll use some of this for future samples that require it, like the rare earths or alkali metals.

Brain&Force - 15-10-2014 at 12:12

Quote: Originally posted by careysub  
Quote: Originally posted by Oscilllator  
Why would the EU be cracking down on tritium sales? Do they think people are going to extract the tritium to convert the fission bomb they already have into a fusion bomb??


Just the usual consumer safety considerations.

10 curies is a lethal dose of tritium if absorbed as tritiated water, and no fluid flushing is used for treatment.

The US does not permit the sale of tritium gas tubes at all, I believe. All the sources of these are European or Israeli.


Tritium has been considered a "strategic resource" by the government thus sales have been restricted.

careysub - 15-10-2014 at 14:20

You can buy tritium emergency exit signs in the U.S. They cost $275, and have 25 curies of tritium gas among the various tubes making up the display.

Although no license is required to buy one, the device itself is registered with the NRC and garbage disposal is forbidden.

http://www.exitlightco.com/category/Power-free-Self-luminous...

BTW tritium gas is harmless since the body's absorption/retention of elemental hydrogen gas is negligible. The toxicity of unoxidized tritium-hydrogen is at least 10,000 times less than HTO. If a sign gets burned up the tritium can be oxidized.

diddi - 15-10-2014 at 15:31

find someone with a MIG welder. they all use Ar. the amount you use would cost about 5 cents! that's what I do.

neptunium - 22-12-2014 at 21:46

68 elements out of 84 (potentially) ! slowly getting there!


number 2.JPG - 739kB


I know it is not as fancy and awe inspiring as Mrhomescientist's, but i am still proud of it and I love to show it !


[Edited on 23-12-2014 by neptunium]

phlogiston - 23-12-2014 at 01:27

Classy, nice.
There appears to be something in the actinium box, but it is difficult to see in the picture. What is the sample? Similarly, what is your Po sample? it doesn't look like an atistatic brush.

neptunium - 23-12-2014 at 11:28

it is ! just the strip tho in a small glass vial. Actinium is just a sample of Euxenite...i made a gamma spectrum of it and Actinium is clearly present

diddi - 23-12-2014 at 15:51

well, wouldn't it be nice if we all had a gamma spectrometer? LOL
I have a euxenite specimen, will there always be Ac present? I assume it is a decay product. is there any way I could verify Ac presence in a sample without popping into my local university? its not an area I am very up to date on.

neptunium - 23-12-2014 at 19:23

http://www.sciencemadness.org/talk/viewthread.php?tid=27963&...

send me a sample

careysub - 23-12-2014 at 21:26

Quote: Originally posted by diddi  
well, wouldn't it be nice if we all had a gamma spectrometer? LOL
I have a euxenite specimen, will there always be Ac present? I assume it is a decay product. is there any way I could verify Ac presence in a sample without popping into my local university? its not an area I am very up to date on.


Any sample of a natural uranium mineral will contain an equilibrium amount (i.e. same decays-per-sec as the parent U-235) of Ac-227. U-235 decays into Ac-227 (half life 21.77 years) in a three step process with Pa-231 the slowest link (32,760 years) - so Pa-231 is also present in an equal-decay amount (but over 1,000 times more by mass). Confirmation through gamma spectroscopy is interesting, but hardly necessary.*

Natural uranium ore specimens allow you to accurately claim all (but maybe one) of the members of the decay chain, there will be at least some of every one of them, even the super-rare francium if you have at least a milligram of uranium in the sample.

The super-super-rare astatine I am not sure about - all of the production pathways are rare, and no good estimate of the likely content is at hand. I'll have to work that one out a bit.

*It may set-up a nice sideline selling radioactive samples with their accompanying gamma spectrograms.

[Edited on 24-12-2014 by careysub]

[Edited on 24-12-2014 by careysub]

Attachment: U235.svg (94kB)
This file has been downloaded 719 times


j_sum1 - 23-12-2014 at 21:32

If someone did that, I certainly would be interested. Bagging a bunch of the unobtainables for the element collection would be a coup.
edit
I still would like a gram or two of depleted uranium though. Having evidence of some decay products would be great but having a visible sample of the great bogeyman element is still desirable.

[Edited on 24-12-2014 by j_sum1]

diddi - 24-12-2014 at 04:45

@Np
I have quite a few minerals: pitchblende, monazite, samarskite, ellsworthite, polycrase, davidite, autunite, allanite, thorite, fergussonite, uraninite, aeschinite, euxenite, trinitite
and possibly some others I cant remember right now :)

phlogiston - 24-12-2014 at 05:18

Although it would require extensive planning to avoid contaminating the lab, for an element collection it would be nice to extract the various radio elements into separate samples, so one can put them in separate boxes of a periodic table (even if they remain 'diluted' with stable elements, eg. radium salt in a matrix of the barium salt, polonium in a bismuth fraction, actinium in a rare earths/lanthanum fraction, etc.)


[Edited on 24-12-2014 by phlogiston]

neptunium - 24-12-2014 at 12:48

Quote: Originally posted by careysub  




*It may set-up a nice sideline selling radioactive samples with their accompanying gamma spectrograms.



it is the original idea i had a while back...this periodic table is 20 some years in the process... time and money are a major issue sometimes.

i was going to print out the spectrum and glue it to the back of each compartment with a little arrow pointing at the peack responsible for (fill in the blank) proving its presense.

careysub - 24-12-2014 at 13:50

Quote: Originally posted by neptunium  
Quote: Originally posted by careysub  




*It may set-up a nice sideline selling radioactive samples with their accompanying gamma spectrograms.



it is the original idea i had a while back...this periodic table is 20 some years in the process... time and money are a major issue sometimes.

i was going to print out the spectrum and glue it to the back of each compartment with a little arrow pointing at the peack responsible for (fill in the blank) proving its presense.


You could offer this service to SM members for a reasonable consideration to offset the cost...

diddi - 24-12-2014 at 19:49

does anyone have access to a gamma spectrum library? I have bee googling but turning up nothing.

diddi - 25-12-2014 at 02:48

I found an interesting graph and text pertaining to abovementioned "radioactive equilibrium" here:
http://www.laradioactivite.com/en/site/pages/Radioactive_Equ...

the graph for U238 is nice:


equiUranium_En.jpg - 59kB

neptunium - 25-12-2014 at 07:51

Quote: Originally posted by careysub  

You could offer this service to SM members for a reasonable consideration to offset the cost...


i did
http://www.sciencemadness.org/talk/viewthread.php?tid=27963#...

MrHomeScientist - 6-1-2015 at 18:53

Seeing this thread bumped encouraged me to post an update. It also made me realize I really need better lighting for my display area! Getting half decent pictures was tough.
Here's the state of the table as of today. The only elements I have left to collect are As, Rb, Pd, Nd, Lu, Hf, and Ir.

1.jpg - 239kB

After those, there are several samples I'd like to improve. Blogfast's work with light bulb filament support wires has thrown doubt on my Mo sample, for example. Also all elements from Po to Pa are currently represented by uranium ore samples, so at least some of these could be better (like Th).

On the table the display rests on, I have some extra neat things that either won't fit on their shelves or aren't really elements.

From left to right: Teflon cylinder, uranium doped marble, aluminum ingot (melted from soda cans), just over 1 kilogram (1061g) of mercury, white phosphorus stored under water, lithium slugs under argon, and an ultra pure silicon crystal boule.
2.jpg - 257kB

And then some gold ore samples and a fluorite octahedron in the left picture, and my mini collection of sulfide minerals on the right. The two unlabeled ones are galena at the top and molybdenite on the bottom right.
3.jpg - 314kB 4.jpg - 289kB

j_sum1 - 6-1-2015 at 19:08

This is ultra cool. I am really excited to see how it has progressed.
I saw some Ir on ebay recently at a good price. U2U me if you want details.

MrHomeScientist - 7-1-2015 at 06:23

Thanks! It's been lots of fun filling the shelves. U2U sent.

neptunium - 27-4-2015 at 06:23



resized.jpg - 1.4MB resized2.jpg - 1.1MB resized3.jpg - 1.5MB

only 6 more to complete it !..

phlogiston - 27-4-2015 at 11:53

Nice, thanks.

Is there anything that physically prevents the bromine flask from rolling out of its box?

[Edited on 27-4-2015 by phlogiston]

MrHomeScientist - 27-4-2015 at 11:57

Awesome! What all do you have left to collect? What is in your polonium vial?

Zombie - 27-4-2015 at 14:43

Quote: Originally posted by MrHomeScientist  
Very recently I finally completed a pretty massive project that I thought I'd share with you all: a large periodic table display for my element collection! I designed and built this myself, since my element collection has grown large enough where I think it deserves a nice display unit.

Broad overview: it is a large freestanding display unit with individual acrylic shelves for all 118 elements (plus two placeholders for the lanthanide and actinide series'), with the shelves backlit by LED strips. The display is able to be broken down into four pieces, to allow for easy transport. The LEDs are controllable via an Arduino "master controller" and several LED driver boards mounted to the back, allowing for some really neat effects. In the future, I plan to write a tablet app that can control the display via a periodic table GUI. That will enable things like Quiz mode, where multiple choice questions can be asked, the answers lit up on the board, and the correct one flashing (or something similar).

I put together a video summarizing the build and showing it in action:

<iframe sandbox width="560" height="315" src="http://www.youtube.com/embed/LSY_DKQv4g0" frameborder="0" allowfullscreen></iframe>

I go into much more detail on my blog, in a series of posts starting with the introduction: http://thehomescientist.blogspot.com/2013/02/the-element-dis...

I won't attempt to replicate all that info here, but here are a few fun facts about the display:

- Design time: 3 months
- Construction time: ~1 year (working during my free time)
- Dimensions: 48" tall x 65" wide (about 4 ft x 5.5 ft)
- Number of holes drilled: 361
- Cost: ~$1000 (not including the actual elements, or all the prototyping materials I went through)
- Current collection: 51 pure elements, 10 elements represented by radioactive decay products (U ore), and 2 representative compounds (Teflon and AmO2)


Soon I'll be going through my whole collection in another set of videos as well, so stay tuned for that!



Dude!

You sooooo nailed it.That is just amazingly cool.

You know... I can easily see 700.00 - 1,300.00 bucks for these retail.

That's a Shark Tank episode waiting to happen.

szuko03 - 27-4-2015 at 15:18

"That an amazing idea I wish you all the luck but it's too niche for me, I'm out."

But ill probably be borrowing from your idea in a decade or so. Ill try to give credit because it's way too amazing for me to claim.

[Edited on 27-4-2015 by szuko03]

neptunium - 27-4-2015 at 21:52

Quote: Originally posted by phlogiston  
Nice, thanks.

Is there anything that physically prevents the bromine flask from rolling out of its box?

[Edited on 27-4-2015 by phlogiston]


nope...just the thick glass ampoule!....and carpet!
its fine it hasnt rolled off yet

neptunium - 27-4-2015 at 21:54

Quote: Originally posted by MrHomeScientist  
Awesome! What all do you have left to collect? What is in your polonium vial?



static brush from static master..
http://www.amazon.com/Static-Master-Brush-1-Inch/dp/B0000AE6...
the strip has a pretty god Po210 source in it..

j_sum1 - 27-4-2015 at 22:44

Quote: Originally posted by neptunium  
Quote: Originally posted by MrHomeScientist  
Awesome! What all do you have left to collect? What is in your polonium vial?



static brush from static master..
http://www.amazon.com/Static-Master-Brush-1-Inch/dp/B0000AE6...
the strip has a pretty god Po210 source in it..

I have heard that before -- probably from Theo Gray. Thanks for the reminder.
(Po is probably one of the lower priorities for my collection however. I should do a count, but I am only about half way with all of the expensive ones to go.)

MrHomeScientist - 28-4-2015 at 12:59

Awesome! Pretty expensive, plus you have to replace it every ~470 days! (the time I calculated it to decay to 10% remaining Po) I'd love to get one of those. If it's possible to cut off a piece of that strip I'd be willing to trade for it :)

I have my bromine sample similarly precariously placed on its shelf. "It hasn't fallen off yet" won't sound so good after it does fall off! Ideally I'd like to encase mine in acrylic, but in the meantime maybe some sort of base/stand for it would be a good idea. In your case, you could put a dowel of some sort across the 'cubby' to keep it secured.

Thanks very much for the praise on my table, by the way :D The display plus all the samples would end up being pretty expensive if I were to turn it into some sort of product; the samples probably double the overall price. Now that I've taken it to several events, I'd really like to sit down and redesign it to be more sturdy. More like a cabinet, with windowed cells so the samples are secure in their places and people can come right up to the display without fear of knocking anything over. The compartments would open from the back so I could still take samples out to show people. Something like that, anyway.

szuko03 - 28-4-2015 at 13:22

Quote: Originally posted by neptunium  
Quote: Originally posted by MrHomeScientist  
Awesome! What all do you have left to collect? What is in your polonium vial?



static brush from static master..
http://www.amazon.com/Static-Master-Brush-1-Inch/dp/B0000AE6...
the strip has a pretty god Po210 source in it..


Wow I had no idea they made anti static brushes with radioactive elements. It just seems like a waste for something so expensive and rare in a sense.

[Edited on 28-4-2015 by szuko03]

veganalchemist - 9-1-2017 at 13:05

Here are a few pictures of my Periodic Table.

I finally got my EPP licemce from the Home Office (UK).





Periodic Table.jpg - 1.2MB Group 11.jpg - 1MB

I normally have it covered with a perspex sheet.

The Silver coin is a 2014 UK quarter ounce siver coin struck from the silver recovered from the SS Gairsoppa. Got it from the Royal Mint. You get a really interesting booklet and DVD about the salvage operation.
The wreck is at 4 700 m (The Titanic is at 3 700 m).


The gold bar is a 5 g 999.9 fine gold bar, also from The Royal Mint in Wales.




MrHomeScientist - 9-1-2017 at 14:17

Looks great! Nice work.

I'm curious what you have for your radioactive samples: Po, At, Rn, Fr, Ra, Ac, Pa, Np, and particularly Pu?

j_sum1 - 9-1-2017 at 14:34

That is a gorgeous display and an even more gorgeous collection. Well done.

What did you use for F?

veganalchemist - 10-1-2017 at 14:54

I need to replace some of the reactive metals in oil as they are badly corroded.


Po is from an antistatic brush.

At, Fr and Pa are from pitchblend.

Rn is from some thorium nitrite.

Ra is a luminouse watch hand.

The F sample is a 33% F sample in nitrogen. Prabbably escaped by now. Given to me as a Christmas pressent from a good friend.

And finally the Pu is a sample of Trinitite.









nezza - 12-1-2017 at 02:04

Here is my effort at a periodic table with a few notes.

1. I deliberately stopped at Bismuth as radioactives are impossible to get in elemental form in the UK.

2. There are some gaps. I am trying to find a supplier of small amounts of rubidium (0.5 to 1 gram) as the current ebay offerings of 20mg are too small.

3. There are more gaps around the noble metals (Osmium etc as they are very expensive)

4. For the Noble gases I have used a photo of the gas discharge glow for each.

5. For Fluorine I use a Fluorite crystal which can be illuminated with UV as I'm never going to get hold of visible amounts of fluorine.

6. The other colourless gases ??.

Periodic table.jpg - 248kB Non metals.jpg - 279kB Precious metals.jpg - 168kB

diddi - 12-1-2017 at 03:27

very nice guys...

pantone159 - 12-1-2017 at 07:38

I do not have as nice a display as some of these, but for F, I do have a sample of antozonite, which contains small amounts of elemental F. It does not look as interesting as the usual fluorite crystals, but I still like it.

https://en.wikipedia.org/wiki/Antozonite
http://www.nature.com/news/stinky-rocks-hide-earth-s-only-ha...


MrHomeScientist - 19-1-2017 at 19:42

Quote: Originally posted by pantone159  
I do not have as nice a display as some of these, but for F, I do have a sample of antozonite, which contains small amounts of elemental F. It does not look as interesting as the usual fluorite crystals, but I still like it.

https://en.wikipedia.org/wiki/Antozonite
http://www.nature.com/news/stinky-rocks-hide-earth-s-only-ha...


Me too! A commenter on one of my videos mentioned it, and after searching around eBay for a long while I finally found a sample. I was very excited to learn about a way to have elemental fluorine for my collection!

20170119_213535_001.jpg - 708kB

They are the little black cubes (actually very dark purple), growing on a quartz crystal.

my periodic display

CouchHatter - 3-7-2021 at 18:45

I have been imagining this for a couple of years. Finally put in the work to build it - now the collecting can begin in earnest!

I skipped on the lights, only because I'd already spent as much time as I cared to building it. It took 20+ hours of marking and cutting, routing and sanding, painting and folding to realize this much of it. And I am starting school so I wanted to have this up on the wall not on the shop floor.

Now to tidy up my neglected lab...

IMG_20210703_212045_337.jpg - 2.7MB