This glow in the dark slime is sure to put anyone in the Halloween spirit. The kids’ science activity is simple to make but provides hours of imaginative sensory play.

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Glow in the Dark Slime Recipe

For this experiment you’ll need to gather a few supplies:

  • 2 bottles of Elmer’s white school glue {4 oz each}
  • 1 bottle of glow in the dark paint {2 oz available at craft stores or online}
  • food coloring {we used neon green and orange}
  • 1/2 cup liquid starch {we used Sta-Flo brand}
  • black light (optional, but charging the slime with a lamp doesn’t yield as bright a result)

Once I gathered the supplies, I called my 4 year old, A, over and had her empty the 2 bottles of glue into a large bowl.  Then I filled the glue bottles with warm water and had A shake them to remove any of the remaining glue.  A poured the water from the glue bottles into the bowl of glue and mixed it well.


Next, A added 4 tablespoons of the glow in the dark paint into the glue mixture, added a few drops of food coloring, and stirred until combined.

Finally, I handed A a measuring cup with 1/2 a cup of liquid starch.  “What do you think will happen when we add this starch to the glue?,” I asked.

“It will get thicker,” A replied.  I told her to pour little in a time and stir.  The trick is to go slow. Too much and the slime becomes tough – too little and it’s sticky.  As soon a A added the starch runny strands of slime began to form.


A continued adding about a tablespoon of starch until the slime seemed thick enough.  The texture was still runny, with some thicker clumps and some puddles of water below.  At this point A couldn’t wait to dig right in so we finished mixing and kneading the slime with our hands.  As we mixed the water puddles disappeared and the slime became smooth and stretchy.


“Can I play with it now?” A begged and giggled as she pulled a large strand from the bowl.  “It’s so slimy and goopey,” she said laughing and laughing.

She quickly discovered if she poked holes in the slime with her fingers the holes would slowly disappear.  Next,  she tried stretching it as far as she could, even standing on her chair in order to hold the slime “way high up”.


When she discovered the slime snapped when pulled she began pulling strands apart to make little bits of “dino snacks”.  I grabbed a few dinosaurs and after she fed them. She stomped them through the slime making feet impressions that magically vanished after they moved on.  A’s little brother couldn’t resist the fun and since this recipe is made without the possibly irritating borax I felt it was ok for him to join in.  The dinosaurs stomped around getting stuck in the sticky “tar” and leaving fossils behind for a good 45 minutes and we hadn’t even turned on the black light yet.


Later that evening we pulled out the backlight out and we all got into playing with “ogre boogers” and witch’s magic potion.  A got out a few “cauldrons” {jars} and a butter knife and began cutting bits of magic ingredients to add brew.  Her little brother is obsessed with using scissors and helped by cutting off pieces to add to the pot.  “Wouldn’t this be fun to give to your friends for Halloween?” I asked A.  “Oh yes!” she exclaimed.  She can’t wait to give all her friends a cauldron of glow potion and since it was so simple to make I don’t mind helping her.

Super awesome glow in the dark slime. {Playdough to Plato}

The Science Behind Slime

What you formed when mixing the glue and starch is called a polymer.  A polymer can act like a liquid and solid.  You can pick it up, mold it, and cut it like a solid, but if left alone it flows and takes the shape of the container it’s in like a liquid.  A polymer can do this because it is made of long chains of molecules.  When the long chains of molecules can flow and slip past each other, like cooked spaghetti in a pot of water, then the polymer acts like a liquid.  When the molecules stick together in a few spots, like drained spaghetti left out, then the polymer acts like a rubbery solid.  When you added the starch to the glue the starch hooked the molecules of glue together forming the slime polymer.

The Science Behind the Glow

Glow in the Dark products contain a substance called a phosphor.  Phosphors slowly re-emits visible light after being energized.  When you charge your slime using a strong lamp or using the ultraviolet light of a black light the phosphors become energized and will radiate after the lights are turned off.

More Science with a Wow Factor

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