Have you seen the latest craze – I bet you have and you’ve probably caught your kids watching how to video’s on YouTube right. It’s all about making slime! Well, I won’t be letting my kids make it and I sometimes wonder if I am alone in this.

A high school chemistry teacher reveals why the current craze for slime making won't be happening in her home and explains why

Now don’t get me wrong I love slime!

Here’s what we use for a tactile sensory experience instead of Slime at home:

In fact, it was one of my favourite experiments to do with my high school chemistry class to show reversible bonding in polymer chains and was an ideal experiment to induct students into inorganic chemistry.

But… you are not going to see it in my home unless I am making it to demonstrate this reaction to my kids in a chemistry experiment. Instead, I will buy slime for them to play with or use one of these Easy Slime recipes from Red Ted Art if they want to play with slime.

Why I won’t be letting my Kids Make Slime! – The reasons

So why won’t I let them make slime? Firstly we can’t ignore the materials being used in the experiment….

The Chemicals being used

BORAX – this is a chemical that is restricted in the UK that means that the powers that be have decided that through the evidence presented to them by scientists it is too dangerous to be sold easily over the counter. Yes, you can get it, and I have a supply that I use to make body products at home but notice that I use to make them.

I’ve seen liquid laundry starch and laundry detergent being recommended to use to make slime as well – let’s take laundry starch.

In the UK if you can actually find some LIQUID LAUNDRY STARCH then it will contain Sodium Borate. Guess what – Sodium Borate is otherwise known as BORAX!. And laundry detergent, the chemical composition of most are heavily guarded secrets and each is slightly different so using a laundry detergent well which one, is it the same when brought in the US and UK or how about have they changed the recipe (something that happens frequently just listen out for all of the adverts claiming the NEW IMPROVED…….!)

Now, there are people that say that restrictions are overkill and also those that insist on using it for years to clean and not having any known effects but from my experience of using it in a chemistry lab, the risk assessment and the CLEAPPS card that accompanies the use of Borax is LONG. It’s considered TOXIC in solutions over 8.5% as it may cause infertility and harm to the unborn child. Not to mention that it is a fairly common allergen, ever had a reaction to a new washing powder there is a possibility that that could be a borax reaction.

Polyvinyl alcohol – well I have bottles and bottles of it at home, we use it regularly it’s PVA glue, white school glue or Elmer’s glue.

The measurements

So what does a solution of 8.5% borax look like – well let me tell you the maximum solution we used in the lab was 8% and it was made up in a fume cupboard and using our highly accurate scales. Can I remember the instructions to make the solution…. NO! From looking at some of the recipes – I’ve seen some that are accurately measured, but others well the measures being used are teaspoons, cups, sprinkle none of which are particularly accurate and even these are open to interpretation as I’m sure you know from cooking.

When I did this experiment the kids wore safety goggles and gloves – why? Because it is a chemical reaction and then they used gloves to play with the slime that we had made. Why? Because here’s a fact kids and adults are not always accurate in their measurements and me as a teacher could not be there with every child in my class supervising the pouring of the chemicals and measuring them out so although slime was made I was never sure what exactly they had measured.

And in a couple of cases in each class, their measurements were so out despite instructions and easy to read apparatus we never even ended up with Slime just a mess.

The apparatus

Now…. I taught high school chemistry I’ve made lots of slime. BUT… at home no there is another big consideration when your child is making slime that you probably haven’t thought about.

Slime is a chemical reaction – in the classroom, we use thoroughly cleaned apparatus to make it, these go through cleaning by our lab technicians, or at least in all of the high schools that I have taught at, after each class. That cleaning gets rid of all of the residues of chemicals from other experiments. At home, I wash my dishes in the dishwasher or by hand. I kind of know what they are being used for, but could I guarantee that there wasn’t something there that would react – well NO!


Slime is non-toxic, but it goes mouldy, it gets dirty especially when handled and it blocks the drain! Trust me it really does block the drain! You can reverse the reaction breaking up those links between the polymer chains using an acid but do you really want to start doing that so when you have made the slime what do you do with it!!!

Making Slime – it’s your parental choice

If your kids suddenly come and say to you – I want to make slime, then make an informed decision on it, decide whether you want them at home to make a high school chemical reaction to demonstrate polymer chain bonding or Non-Newtonian Fluids and if just those words fills you with shudders remembering your own high school science lessons then instead go out and buy some or give a try at some of the recipes linked above which involve none of the reactions or try making gloop which has many of the same properties and uses ingredients from your kitchen cupboard.

Think about what they and you are using this potentially toxic and complex reaction for, if it’s for play then find something else that fills the same job. If you are using it for science then find a science textbook that gives you the correct measures to make this great science experiment safely and use it for learning.

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A high school chemistry teacher reveals why the current craze for slime making won't be happening in her home and explains why

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A high school chemistry teacher reveals why the current craze for slime making won't be happening in her home and explains why

Cerys Parker

Cerys is a marine biologist, environmental educator, high school teacher and mum. Realising that life doesn't have to be put on hold and you don't just have to survive whilst the kids are young she shares ideas to inspire you to LIVE with the kids, with activities to do together, recipes to cook and enjoy and family travel to make memories to last a lifetime.


  1. That’s just silly in my opinion. Store bought slime usually contains the same ingredients such as boric acid…and if it were so toxic…why would it be used to clean contact lenses? Seems a bit overboard to me….why not just teach them to appropriately make it?

  2. Do you have a good recipe for getting it to dissolve in the drain??? My kids just poured some down the bathroom sink!!!!!

  3. YOU CAN MAKE NONE TOXIC SLIME THESE DIffrent WAYS: MIX Hand soap with sugar, mix well untill ingredients get hard to mix then let stand for two days for slime to form , last step kneed the slime. Glue and laundry detergent only slime recipe, look up recipes online to show measurements. Glue and body wash only slime recipe, look up online to show measurements.

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