We’ve had so much fun making this amazing colour-changing thermochromic slime using thermochromic dyes. This is a slime that changes colour at just 31oC …..and the best part is that you can now make your own colour changing slime using our Thermo Slime Kit! Read on & watch the video too…..





Grab our Thermo Slime Kit (order here) or you can buy your own thermochromic dyes, PVA glue and slime activator.



First protect the work surface with a plastic cover or work on a tray. If you’re using our kit you can follow the instructions that come with it. If you’ve got your own materials then these steps will help:

  1. Add about a large slosh of PVA glue into a bowl (or one of the pots if you have our kit)
  2. Sprinkle in some thermochromic powder, the amount depends on the intensity of colour you want to achieve, we recommmend using a small amount. If you’re using thermochromic liquid, then add a few drops. This stuff goes a long way!
  3. Stir the dye in really well, it may take a while to blend in as it can clump together at first.
  4. Now add the activator a little at a time, until the slime started to form and pull away from the sides of the bowl.
  5. When it pulls away from the sides of the bowl, and isn’t runny or too gloopy, then you know the slime is ready to be moulded, stretched and squished using your hands. This is the last stage of slime-making and although messy to start with, as the slime forms it comes off your hands and gets less sticky. If it doesn’t get less sticky and is still a mess all over your hands, just squirt a bit of activator directly into your hands and continue to mould your slime, you’ll feel the slime form and get less sticky. Keep doing this until you are happy with your slime. Too much activator and the slime goes hard and rubbery, so you want to add just the right amount.

You might notice the slime changing colour as you play with it! You can make it change by bringing it close to a cup of tea, or put it on a warm plate, or near a radiator. It changes back when it cools down again.

Order the Thermo Slime Kit here



How to make thermochromic slime (video)

please note: in this video I am using clear glue but you can use normal white pva glue



Lab notes

What is thermochromism?

Thermochromism is the property of certain substances to change colour when the temperature changes. A mood ring is a well known example of a temperature sensitive item. The dyes have been manufactured to change colour at a certain temperature, so for the colour changing slime we chose a dye that was sensitive to 27oC so that it would change as it warmed up in our hands. There are several useful applications for thermochromic dyes, such as thermometers and hot drink indicators. There’s the fun side too, as in jewellery, colour changing t-shirts and slime!


Want more slime recipes?

Check out our other “How To” blogs here:
Magnetic slime
Fluorescent/Hallowe’en slime
Fluffy slime



Good luck & happy sliming

If you tackle this activity at home you do so at your own risk.

If you have as much fun as we did, please tag your pictures with us @devonscienceuk on Facebook.

Bye for now

Chief Scientist at Devon Science

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