Illuminated Discovery Bottles

While in a craft store recently, I came across submersible lights. Immediately my wheels began to turn and I began to think of the possibilities. I bought a pack of submersible lights and some water beads, and made these illuminated discovery bottles for our science center.

Illuminated Discovery Bottles

The materials I used were submersible lights, water beads, and large plastic test tubes. My set of Jumbo Test Tubes are from Lakeshore, but you could also use plastic drink bottles that have a wide mouth.

Submersible lights (from a craft store):

Submersible Lights

Water beads (also from a craft store):

Water Beads

Lights & Glitter

This discovery bottle has water and red glitter with the submersible lights. The lights sink to the bottom, but when shaken, the lights move around in the water with the glitter. The light illuminates the water and reflects off the glitter, making it sparkle as it swirls around.

Illuminated Discover Tubes

Disappearing Water Beads

In this discovery bottle, I put in some clear water beads. I first showed the children how small the beads are when they are dry. Then I placed them in a test tube with water, and left them alone to absorb the water and grow bigger.

Water beads: before & after

After the beads were full size, I added some water to one of the tubes until the water covered the beads. This makes the beads seem to disappear!

Disappearing Water Beads

The water beads can only be seen when you move the tube around or lay it on its side.

Disappearing water beads appear again

Lights & Water Beads

Then I placed the submersible lights in the two bottles. The water beads hold the lights in place, so this time they don’t sink to the bottom. Children can either observe the bottle when it is completely still or shake and move the bottle to watch the lights move around among the water beads. In the picture below, the blue test tube is the one that has only water beads with no extra water added. The yellow test tube is the one that had extra water added to it. This tube makes it appear that the lights are suspended in the water, when they are actually sitting on top of invisible water beads.

Illuminated Discovery Bottles

Here’s a challenge for you: In the comments below, tell your own ideas for making Illuminated Discovery Bottles. After you make them, come back and tell us how they turned out!


  1. Angelika Stablow says

    You could add food coloring or liquid water color to the water for different color effects, and/or liquids with a different density (glycerin or mineral oil).

  2. Gloria says

    How long have you kept the water beads sealed in a container (test tube or otherwise)? I am wondering about mold. That being said, though, I can’t wait to try this! Thanks so much for sharing!!

    • says

      Mold would depend on the amount of humidity in the room. Being almost winter now, it shouldn’t be a problem for a while. You probably wouldn’t leave them in there all year. If it did grow mold, you could just throw away the water beads and wash the tubes in bleach water. I haven’t had mine in the tube very long. Usually when I do an activity with my class, I post it while it’s “fresh”, lol.

  3. Jennifer says

    What a great idea! In the past I have added light corn syrup to the water. It slows down the movemnet and gives more of a lava lamp appearance.

  4. Sue Brooks says

    A few ?’s..Are the H2O beads poisonous if swallowed? How do the lights on/off switch operate? Curious about fishing them from the tubes.
    This is an awesome idea with lots of potential for discovery with children and adults sharing the experience. Lots of language going on, for sure. Many thanks!

    • says

      Water beads are made of a superabsorbant polymer. Same thing that’s in diapers and instant snow. They’re supposed to be non-toxic. The kids are not playing with the beads themselves. The beads are inside a bottle, which you can seal with masking tape wrapped around the lid several times, or some duct tape.

      • Cyndi says

        I’ve let my preschool children play with the water beads. They feel really cool. We use the same rules as instant snow and water play…wash your hands first!

  5. Laura Brian says

    Hi. These are so great. I recently made some with letters and fuzzy pipe cleaners in. The children then had to manipulate the pipe cleaners around the bottle with magnets to see the letters. They loved it and it kept my investigation area full of children all week! :-)

    • says

      Can you post a picture of your idea? I am a visual learner so I need to see how you put the letters on the pipe cleaners. It sounds like another fantabulous way to introduce the alphabet and possibly numbers….Thanks!!

  6. Lu Amily says

    Many thanks to Karen :
    Thank you so much for providing such wonderful ideas about pre-kinder teaching,what a loving deed,Karen,I am a chinese christian , have been looking for christian teaching resources for my girl and other little kids from our church,then your website is here! thanks to almighty God

  7. Tamera Vanhorn says

    I just found a 2 pack of these submersible lights at Meijer on Clearance for $2.79 in the floral department. Water beads can be found sometimes at the Dollar tree, WalMart and in several teaching catalogs, I also think at Oriental Trading. I can not wait to try these. Thank you for the awesome ideas!!! Keep up the good work everyone.p

  8. Valerie says

    I love the lights idea. You just gave me some ideas for Valentine’s Day, I have some tiny plastic confetti hearts that never get used because of my little one. I think I will make a rainbow set with different items in them for St. Patrick’s Day. Last year I made a tube like you did with the clear beads and told them they were magic Leprechun eggs and that’s why we can’t see them because they were magic. You should have seen their faces it was priceless. I love my job. Thank you for sharing your amazing work with us. You amaze me.

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