Make Stretchy Universe Slime!

an image of a hand holding purple universe slime with lots of glitter

Did you know that our universe is stretching out in all directions? It's true! Ever since the universe began about 13.8 billion years ago, it's been stretching out and expanding.

Even today, as we use telescopes to see galaxies far away, we see they are moving away from us. And that’s not all. The farthest galaxies are moving faster than the ones close to us.

This happens because of how the universe began, which we sometimes call the "Big Bang."

In this activity, you'll make your own stretchy universe slime.

What you need:

a photo of a teaspoon of borax, school glue, red and blue food coloring, glitter, measuring cups, two bowls, and wax paper on a table top

  • Clear school glue
  • 1 teaspoon of borax
  • Water
  • Red and blue food coloring
  • Two bowls
  • Measuring cups: 1/2 cup and 1 cup
  • Glitter
  • Wax paper


Do not eat borax, and don't wipe it in your eye.

Borax is safe to use, and in fact is an ingredient in many laundry soaps, but do NOT put it in your mouth. You also don't want to have it on your hands and wipe your eye. If you do, rinse thoroughly with water. Refer to the borax package with any other safety concerns.

What to do:

  1. In one bowl, mix 1/2 cup of glue with 1/2 cup of water. Stir it together; it will mix nicely.

  2. pouring glue into a half cup measuring cup pouring glue into a bowl filled with water

    Note: You may also use white school glue, but your universe slime will be lightly colored and opaque.

  3. Add food coloring to the glue and water mixture. We used 6 drops of blue and 3 drops of red to get a nice, dark purple color.

  4. swirls of blue food coloring in the water and glue mixture purple glue and water mixture in a bowl

  5. In the other bowl, mix 1 teaspoon of borax with 1 cup of lukewarm water.

  6. adding borax to a bowl of water

  7. Stir until the borax is dissolved. This takes a while, so you have to be patient. If you skip this step, your slime will not come together very well.

  8. Stir, stir, stir, until you don't feel the crunch of the solid bits of borax on the bottom. The water will start to look a little cloudy.

  9. stirring the borax into the water so it dissolves

  10. Add the purple glue mixture to your borax water, stirring slowly as you pour it.

  11. adding the purple glue mixture to the borax solution. the mixture turns into goop when they come into contact with each other

  12. You'll see the slime start to form. Stir as much as you can. Use your hands to get in there and work it around.

  13. the slime in a bowl with extra water

  14. Take your glob of slime out of the bowl and put it on your wax paper. It's okay if there is some water left behind.

  15. the slime is now on the waxed paper in one piecce

  16. It's time to add some glitter galaxies! Flatten out your slime and spread glitter over the top. You can use any color or combination of colors, but lighter ones will work best because they will stand out against the dark purple.

  17. silver colored gliter is poured over the top of the hunk of slime

  18. Fold your slime in half to seal in the glitter. Then press it out and fold it over again.

  19. the slime is folded in half enclosing the glitter inside

  20. Keep pressing and folding and watch as the glitter spreads throughout your slime.

  21. folded a few more times, the slime is now a swirl when viewed from the side

  22. Play with your handheld universe and watch it stretch and expand!

  23. glittery slime on the wax paper a hand squeezes the universe slime to it oozes between the fingers

Storing your universe slime:

To keep your universe slime from drying out, store it in a sealed sandwich bag. Do not wrap it in foil or wax paper because it will stick to those materials.

Download a PDF of this activity.

article last updated October 7, 2020
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