Frequently Asked Questions About Slime

Green Slime (Anne Helmenstine)

I've gotten a lot of questions about making slime, so I figured it would be a good idea to address them in one place. Here are some of the most common slime questions and answers:

  • How do I make translucent slime? How do I make opaque slime?
    Basically, your slime will be about as transparent as the glue you use to make it. If you use white school glue, then your slime will be opaque. If you use translucent clear or blue glue gel (or another see-through color), then your slime will be translucent.


  • Can I mix the slime solutions in advance?
    Yes, you can prepare the borax solution and glue solution days or weeks before actually making the slime.


  • Are borax and boric acid interchangeable? Can I substitute one for the other?
    Borax and boric acid are not the same chemical; borax [Na2B4O7·10H2O or Na2[B4O5(OH)4]·8H2] is a salt of boric acid [B(OH)3]. I haven't tried making slime using boric acid. (Feel free to post a comment if you can offer a more complete answer to this question.)


  • How do I color slime?
    If your glue is tinted, then your slime will be colored. You can mix food coloring in with either slime-making solution. You can also add glitter or other decorations.


  • How long can I keep my slime?
    Slime doesn't go 'bad', but you may want to toss it if it develops mold or if it dries out. Refrigerated slime, kept in a baggie, should last for a couple of weeks. My daughter has a bag of slime (not refrigerated) that she made a few months ago, so it can last much longer.
    Do you have any unanswered slime questions? If so, post them here and I'll update this list.

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