Science Experiment ~ How to Grow Borax Polymer Crystals!

We love science experiments! My 4 year old daughter and I collect rocks. She was so excited when I told her we can grow our own “Crystals” at home, with one household ingredient! It was a lot of fun, we are in love with the beautiful results, especially the rainbow! <3 We used the rainbow and shamrocks as St. Patricks Day decorations! They are so pretty!

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Science Experiment ~ How to grow Borax polymer crystals



  1. Form your shapes and designs with the pipe cleaners
    1. The rainbow was made by laying the colors in order (red, orange, yellow, green, blue, purple)  and twisting them so the red pipe cleaner on top is attached the highest, the orange second-highest and so on. You just have to play with it to get the shape you want. 
    2. The Shamrocks were made by twisting around my fingers (I will add a post with a link here, with directions)
  2. Tie the thread to the side of pipe cleaner designs. See Photos. 
  3. I don’t have exact measurements, with the water and borax. I read online a chemist said, the way to get the biggest crystals is to heat your water then carefully add in borax until it stops dissolving and don’t overdo it, because you don’t want cloudy water, I read it will produce cloudy crystals.
    1. Please Note –  Although Borax is a natural product it should not be inhaled or consumed. Be careful and follow the precautions on the box.
  4. Add hot water & borax mixture to jars
  5. Take pipe-cleaner design with thread, place pipe cleaner in a mason jar, while holding the threads, position it in the jar (so that it does not touch the sides or bottom). If it touches the sides, it will crystallize to the jar. I put the lid on while holding the strings off to the side and sealed with the lid, so the designs were suspended inside. One jar for each design. The rainbow, I used a crockpot and dangled the rainbow hanging from the cupboards. and two others I used a glass bowl. I covered them with aluminum foil, because I read the slower they cool, the more crystals develop. (I don’t know if its true, we are going to test this.)
  6. As the water cools, the powder starts to solidify (turn from a liquid form into a solid form). We let our creations soak & crystallize for 24 hours. I meant to get photos of them crystallizing in the jars. Oops, guys, I forgot. 
  7. When they were done, I removed them from the jars and placed them to dry on paper towels.
  8. Rainbow I added two cotton balls on the front and one attached to the back, with hot glue. 
  9. A few of them I clipped the pipe cleaner parts that didn’t grow crystals, cause not all could be submerged entirely. 
1. I read its best to put one pipe cleaner per jar, you will get bigger crystals.
2. You can use the same borax & water solution, over and over again. Save in a large jar.

3. Try food coloring and white pipe cleaners. We used colored pipe cleaners, next time we are going to see what results we get with food coloring. 


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This Post Has 18 Comments

  1. Tina

    I just got some borax at the store, perfect timing, lol. This looks really fun. What did you guys do with the crystals you made? I am curious also what the borax crystals would be like when food coloring is added.

    1. We hung them for display in the playroom and gave some away as gifts. We do want to try this again and will defiantly have to test some with food coloring! Great idea 🙂

  2. Cassie

    My daughter loves my crystals (I’m a collector), she will go nuts for this. I wonder if I could bend the pipe cleaner in a diamond shape somehow?

    1. You will both enjoy! Yes, we will have to try diamond shapes next time too, great idea – thank you!

  3. Kelsey S.

    The shamrocks are my favorite <3

  4. Joy Fletcher

    This reminds me of rock candy haha, I wonder if there is a rock candy making kit out there somewhere 😉

    1. I’m not sure. It does look like rock candy though! I remember making some with my brothers and parents growing up. I need to make some with my girls! <3

  5. Brittni

    We have all the stuff to make these borax crystals, perfect! I love the 20 Mule Borax and use it all the time in our home.

  6. Tanya

    The rainbow is awesome love it. Great job as usual on the crafts 🙂 I am always saving your links btw! 🙂

  7. Gia Carapelli

    I bet these made fabulous decorations! Did the crystals adhere to the pipecleaners pretty well?

  8. Sarah

    The clouds are the perfect finishing touch to the rainbow! I want to try to make these borax crystals.

  9. Fabian

    I remember making these when I was a kid. My nephew will love this, this weekend!

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