Make Thermochromic Color Changing Slime 

In this science experiment, we walk through how to make color-changing slime with thermochromic properties. Using school glue (PVA glue), borax, thermochromic pigment powder, and water, we create a slimey substance that changes color as its temperature changes! To use this experiment for a science fair project, consider questions like: Does the slime change color faster if you increase or decrease the temperature? Is the slime different when using a bottle of luke warm water vs. a frozen one?


1. Place 120 ml (½ cup) of PVA glue (Elmer’s School Glue) in a 500 ml container.

2. Add 120 ml (½ cup) of warm water to the same container.

3. Sir this solution until it is mixed to an even consistency and set this solution to the side to be used in a later step. This is solution number 1. 

4. In a second 500 ml container add 240 ml (1 cup) of warm water.

5. Add 5 ml (1 tsp) of borax powder to the container and stir until the borax powder is completely dissolved. This is solution number 2.

6. Slowly add small amounts (10 drops at a time) of the borax mixture (solution 2) to the glue mixture (solution 1)  until it thickens into slime. Make sure to continue stirring the glue mixture (solution 1) as you are adding the borax mixture (solution 2). Add about ten drops and then stir these drop into the mixture completely before adding ten more drops.  Stop once the mixture has turned into a slime consistency. 

Note: If too much borax solution is added the slime will be very stiff and not very slimey, so make sure to add solution 2 slowly and be careful not to add too much.  If you end up adding too much borax solution and your slime ends up being stiff and rigid make more glue and water solution and fold the slime in this solution until it loosens and becomes slimy (this can take anywhere from five minutes to two hours depending on how much borax solution was added so it is sometimes easier to start over if your slime is extremely hard and thick).

7. Take your slime and fold it 20-30 times to make sure all the ingredients and mixed well. 

8. Add four to five drops of food coloring to the slime and mix it together by folding the slime 10-20 times. Depending on which colors are chosen you may need more or less food coloring to achieve the desired color.


9. Add 5ml (1tsp) of thermochromic powder to the slime and again fold it 10-20 times until it is mixed completely.  Again depending on which colors are chosen you may need more or less thermochromic powder to achieve the desired color.  

10. Place the slime in the microwave for roughly 10 seconds (depending on the power of the microwave). This will cause the slime to heat to above 33 degrees Celsius (92 degrees fahrenheit) and turn white in color. Cooling it down below this temperature will cause the color to return.  


  • plastic cups

  • school glue (PVA glue)

  • thermochromic pigment powder

  • food coloring

  • ice or frozen water bottle

  • safety goggles

Need supplies for this experiment?
See this list of materials on Amazon.


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