Make a Chemical Garden From Cat Litter, Drain Opener, and Root Killer


Warning: Sodium hydroxide is corrosive. Copper sulfate is toxic. Wear gloves when handling them. Greetings fellow nerds. In this video we’re going to do the famous chemical garden experiment. It’s a nice beautiful experiment and can even be kept as decoration or centerpiece if you wish. Now apologies for the weird filming location and lighting. As you know i don’t have a lab at the moment so i’m filming this in my bathroom. Seriously, my toilet is over there. If you hear any flushing sounds you’ll know why. Anyway, don’t look at this as a disadvantage, at least now i’m forced to do more homemade chemistry that anyone can do even without a lab. Although you will need a digital scale. So let’s get started. First get a tall glass container with at least one liter capacity we add 60g of silicon dioxide based cat litter. This is often called crystal cat litter or silica gel cat litter. Do not use the more common clay based cat litter. Clay will not work for this. We specifically need silicon dioxide. I find cat litter the best for this experiment, even better than sand. Now add in 30g of sodium hydroxide. This is available as drain opener and is often sold as crystal lye. Give it a quick shake. Now for the dangerous part, add in 100mL of water and shake. The water will dissolve the sodium hydroxide and react with the silicon dioxide to produce sodium silicate. The reaction generates a lot of heat and may even boil. We need that heat to drive the reaction forward. Keep shaking to dissolve as much of the silicon dioxide cat litter as possible. The steam generated isn’t toxic, but i do not recommend inhaling it. Now if a lot of it remains then you can leave it overnight and shake again in the morning. I’m going to do that and skip ahead. And here we are. There is still a small amount of cat litter but this acceptable. Now we add an additional 800mL of water to dilute the mixture and get it to the right concentration to make our chemical garden. We didn’t add all the water earlier because we needed high concentrations to make the sodium silicate. But for the chemical garden experiment we need low concentrations. Anyway, shake it until it’s thoroughly mixed. Now get some copper sulfate crystals. Copper sulfate is available as root killer formula or snail killer for ponds. Also get large crystals that are about a centimeter big. If your are too small or a powder then you made need to recrystallize your own copper sulfate. Now carefully drop the crystals in so they spread out. While there is nothing bad about them all bunching together, the final result just looks way better if you spread the crystals out. You can move the crystals with a stick or a straw if necessary. You have several minutes before anything significant happens. Let me adjust the container for a better view. Now all we do is wait. Over the course of a day the crystals will seem to sprout and grow. It almost looks like a stalagmite although the mechanism is completely different. What’s happening is quite fascinating. As soon as you drop the crystals in, the surface of the copper sulfate dissolves but immediately reacts with the sodium silicate solution to form solid copper silicate. This coats the crystal so it’s encased in a layer of copper silicate. But the silicate layer isn’t perfectly impervious or rigid, water can still diffuse in. As it diffuses in it dissolves the copper sulfate underneath and forms a solution. This concentrated solution pushes out as the water continues to diffuse in and increases in pressure. The copper silicate membrane bulges out but eventually it can’t contain the pressure and ruptures. The copper sulfate solution rushes out of the rupture and instantly reacts with sodium silicate solution to form another layer of copper silicate. This layer is newer and weaker so as the pressure builds again it too will rupture and the process repeats. This gives the appearance of a growing structure. It grows upward because the density of the copper sulfate solution is lower than that of the sodium silicate. Now this is rather slow so don’t expect it to be too dramatic. I’m actually timelapsing this over eight hours. An interesting historical footnote about this process is that early scientists a century or so in the past studied this extensively when they were beginning the exploration of the chemical underpinnings of life. The chemical garden honestly looked like a living process made from entirely non-living chemicals. So they thought there was some connection or analogous science going on. We now know that this has absolutely nothing to do with the complex organic chemistry of carbon bonds, lipid bilayers, proteins and DNA. But nonetheless, although it was a dead end, the chemical garden was an honest effort to get started. Anyway, here we are 8 hours later. We got some pretty good growth and even some changes in color as the copper silicates form small amounts of copper hydroxide and copper oxide. Now the growth is still going but my camera ran out of memory space. So i’m going to come back in a couple of days to see the final stage. And here are about two days later. You can see some impressive growth and it looks like we have a chemical forest rather than just a garden. I can see why early chemists thought this might have something to do with life. It resembles seagrass. Now if you want you can drop in more crystals if you feel there is still room. The sodium silicate solution is still active. Alternatively, you can also dump out the solution and do the experiment again in a different container. But I should warn you that the original garden is very fragile and will break up so if you want to preserve it you should leave it in the original solution. As you can see a lot of it is broken. Anyway, you can reuse the solution and drop in new copper sulfate crystals to do it again. Let me try and get a better view. And let me zoom in to get a macro shot of the growth. There we go. Now the solution does get weaker every time you use it so I only recommend a couple of uses before starting all over again. As you can see the growth is not as well formed but it’s still working. The chemical garden experiment was popular for many decades and sold as kits and even as toys. I remember buying a kit when I was younger. But concerns over safety have made them all but disappear. One particular problem is that the chemical salts, like these copper sulfate crystals, look just like candy. I’m sure you can imagine the accidents that resulted with young children. Now you might be wondering if you can use different chemical salts. And indeed you can. Here is one using cobalt chloride. This was a test run so it looks all bad since i tossed in all kinds of substances but it did work. You can use just any metal salt as long as it forms insoluble silicates. So you won’t be able to use sodium chloride or potassium salts as their silicates are soluble. Personally I recommend copper sulfate as it’s the easiest to get and produces the best looking growth. So that was the chemical garden experiment made using crystal cat litter, drain opener, and root killer. Thanks for watching. Special thank you to all of my supporters on patreon for making these science videos possible with their donations and their direction. If you are not currently a patron, but like to support the continued production of science videos like this one, then check out my patreon page here or in the video description. I really appreciate any and all support.

100 thoughts on “Make a Chemical Garden From Cat Litter, Drain Opener, and Root Killer

  1. Well, at least in the event of an unintentional rapid oxidisation of a compound (aka, a sudden loud bang), at least you're next to the crapper to clean up the mess… 😛

  2. Hey, since you have that cobalt chloride, can you do an experiment where you recreate one of those old humidity detectors, with the cobalt chloride crystals that would turn blue or pink depending on the humidity? (I'm pretty certain that was cobalt chloride…please correct me if I'm misremembering it!)

    My mom had a little Hummel-style figurine of a little girl holding an umbrella, and the top surface of the umbrella had a fine layer of cobalt chloride stuck to it. When it was dry, it would be one color, but when the humidity was higher, it would change to the other. I don't remember which color stood for which condition. I'm lucky I remember what chemical it is, since I was about 8 when I first learned about this. I'm pushing 60 now, so it was a long time ago!

  3. The early investigators of the reaction thinking it may in some way be related to the creation of life from non-life may've been more right than they could ever have known!

    See: W Martin and M J Russell, Philos. Trans. R. Soc. B: Biol. Sci., 2003
    "On the origins of cells: a hypothesis for the evolutionary transitions from abiotic geochemistry to chemoautotrophic prokaryotes, and from prokaryotes to nucleated cells"
    and "The Fuel Cell Model of Abiogenesis: A New Approach to Origin-of-Life"
    and "Hydrothermal vents and the origins of life"

  4. Can you change the concentration of the silicate solution to change the diameter of the growths? Or should you use larger crystals? Meh nvm don't answer I want to do SCIENCE!!!

  5. Holy shit. At 6:58 to 6:59 you can actually see a double helix forming ! The two strands used each other as a support structure like a vine going up a tree.

  6. the safety concerns wouldn't be such a big problem if the idea of parental supervision hadn't been completely abandoned

  7. This is the kind of thing that inspires aspiring chemists to keep on experimenting: a great YouTuber making quality content even with extremely limited resources. Keep up the great work!

  8. The blue crystals in the cat litter can be any one of several different chemicals. In the cheap stuff it's usually just dyes, really expensive ones have cobalt chloride as a moisture indicator. I recently made a big batch without removing them and ended up with a light brown suspension that slowly settled out over some weeks – Iron compound? Anyway, I'd recommend removing the blue crystals to get a more consistent result.

  9. Very cool . I will be sure to make one for my office and decorate it will a garden path and little gnome reading a book . I will use a large plastic water bottle that I can drain from drilling hole in bottom in order to not disturb my fragile forest . I may even add some copper sulphate crystal to a string for a boundary hedge ??

  10. This looks awesome! I'll have to see if I can find the stuff for this.
    Would you ever consider doing any "debunking" videos of chemistry "lifehacks"?

  11. I like the idea of using the heat of the sodium hydroxide dissolving in the water, instead of heating the mixture externally.

  12. I forgot about 3 liters of copper sulphate solution months ago I planed to use for lage ammounts of Schweizers Reagent. Got some HUGE crystals out that had just minor defects in them. The largest one was almost 9 cm large! Glad that I didn't pulverize all of the "small" ones yet. Must look great with over 8mm large ones!

  13. Actually Ilan Ramon, the only Israeli astronaut has done the experiment in space and the results were that the crystals grew to all directions in a sphere like shape.

  14. I must add – it's best to use fresh cat litter.
    This is a pretty little experiment, and it really spoils the effect when there is a cat turd floating around on the top.

  15. i accidentally made something like this while playing with household chemicals in my childhood, Got scared …. i thought i created some kind of alien or something…. Little did i know……. Love this … like for science! and Chemistry..

  16. You can get ready-made sodium silicate solution (waterglass) from a home improvement store. It's used as a concrete additive and impregnation agent.

  17. I remember doing this experiment as a kid. I used ‘water glass’ or isinglass, (sold as an egg preservative, IIRC) as the silicate.
    I used copper and ferrous sulphates and cobalt chloride as the ‘seeds’
    It’s nice to see some ‘home chemistry’ experiments on YT again. I used to watch an old channel ‘TheHomeScientist’ which is well worth a look for anyone into this kind of thing.

  18. Flushing sounds OK, other noises might be concerning.. Working with what you got and making the best of it can lead to unexpected discoveries.

  19. You should have given some example of colored crystals for example red green yellow and so on, it could have been really interesting to experiment

  20. so i guess i could use chromatography silica as source of SiO2 ?
    there isn't any specific reason to use cat litter isn't it ?

  21. I remember those kits as a kid. Had a half a dozen different salts for different colors. I guess we just had enough common sense to not eat the stuff. We were also probably age 10+ also. Still a fascinating experiment.

  22. Does having 700k subscribers make it easier to get a job with a university? Or harder. I imagine a lot of places would see it as a liability even if it was just in their minds.

  23. I grew a nice chemical garden using solution of Sodium Carbonate (1.5 molar) that I added a few crystals of MnCl2 to, CaCl2 might work too. I got the recipe from a 1911 book by Stéphane Leduc, The mechanism of life.

  24. "I will never forget the sight. The crystallization vessel in which this transpired (the chemical garden) was filled to three-quarters with a slightly mucilaginous water, diluted water glass to be precise, and from the sandy bottom up rose a grotesque miniature landscape of differently coloured growths–a muddle of vegetation, sprouting blue, green, and brown and reminiscent of algae, fungi, rooted polyps, of mosses, too, but also of mussels, fleshy flower spikes, tiny trees or twigs, and here and there even of human limbs–the most remarkable thing my eyes had ever beheld, remarkable not so much because of their very odd and perplexing appearance, however, but because of their deeply melancholy nature." – From Doctor Faustus by Thomas Mann

  25. Is there a chemical you could put in the solution that would essentially gel up and make it so you could transport the garden easier, or make a more permanent thing?

  26. Is there a reason why you added water to the solids? Typically we add solids to liquids to avoid splashing, or for the reaction to become too hot too quickly when it's endothermic (like adding acid to water instead of water to acid). Do you not have enough material that you don't worry about this, or is it something else? Thank you <3

  27. This can be very dangerous! The bleach of the drain cleaner and ammonia of used cat litter can create deadly chlorine gas. People, Do Not Use Dirty cat litter for this.

    You should also have a vent shield. This is not a project you should do in a house. If you don’t use the proper precautions, don’t have good knowledge of chemical reactions, or are under age, you should not do this without an instructor assisting you.

  28. This is what NurdRage has come to, huh? Filming cat litter in a bathroom…
    Just kidding though, it looks fantastic!

  29. I would not say it got little to do with the way cells form nowadays when considering that currently what is happening in your experiment is considered the proto-stage of life it self – a simple chemical process that gives rise to a more complex structure that acts as a membrane for life.
    Not with the same chemicals of course, but this is one of the most likely candidates for how the first cells (viruses and bacteria mostly) formed.

  30. Thank you!
    Could You also show one day how to make aluminium oxynitride (ALON) and perhaps hydrogen-peroxide (catalytic and electrochemical way). On the latter one there is only one vid from Cody s Lab.

  31. Me: go to bed early, because tomorrow is lots of stuff to do!
    YouTube: hey, buddy, watch a video about how to make a chemical garden with household shit!
    Me: k

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