I first made flubber as a volunteer at the Oregon Museum of Science and Industry (OMSI). Making it with the kids has been one of my favorite science programs at the library.
This program is super easy to run – it really just needs clean up. I’ve split the flubber-making into 6 steps , and run 3 tables of 6 kids each at the same time. There’s a lot of demand, so I usually run two 45-minutes programs back-to-back, with a 15-minute clean up in between. Today I went with ages 5-10, although I think in the past we may have called it grades K-5 – it works out more or less the same. This is pretty easy and appeals to a wide range of ages, so it doesn’t hurt to be inclusive. If they were just playing with it, and not making it, preschoolers enjoy it too.
To begin with, each table gets a large mixing bowl, two one-cup measuring cups, a spatula, and a spoon. If I had more 2-cup liquid measuring cups, I’d give them each one of those as well, but we had to share. At my table, I had the gallon jug of glue (multipurpose or all-purpose white glue, not school glue), a large pitcher of hot water, a 4-cup liquid measuring cup, a one Tablespoon measure, the liquid watercolor, and the Borax.
We start off by talking about solids and liquids. The kids give me some examples and tell me about some properties of each. Then we number the kids from 1 to 6 at each table. I make sure they know their numbers, and then we get started.
Step 1: Pour two cups of glue into the mixing bowl. I come around with the jug of glue and fill both of their one-cup measuring cups. Kid #1 scrapes the glue into the bowl. If they’re super messy at this point, I might take the empty measuring cups off of the tables.
Step 2: Add 1-1/2 cups of hot water to the glue and stir.
Step 3: Choose a flubber color. I pass out the liquid watercolor bottles and Kid #3 gets to put in a few drops and mix in the color. A lot of kids wanted red, so I had to remind them that red watercolor + white glue = pink flubber.
Now there is an intermediate step where I mix Borax and water. For three tables, it works out to 2 Tablespoons of Borax and 4 cups of water. I talk to them about how the Borax is toxic and they should keep it away from their little siblings.
Step 4: This is where the magic happens. I make sure that everyone has gotten to stir the glue-water mixture to see how it feels. Then I come around with 1-1/3 cups of the Borax and water solution. Kid #4 pours that into the mixing bowl and stirs as much as possible before the mixture becomes too hard to work with. I try to make sure that everyone can see the bowl, because this happens very quickly and is very cool.
Step 5: Kids #5 and #6 roll up their sleeves and work in the rest of the water with their hands. Usually the rest of the kids want to get in on this too and there is some sharing.
Once the flubber is done, they dump it out of the bowl and each kid gets a portion to play with for the remainder of the program. It’s usually about 15 minutes to make, 25 minutes to play with, and 5 minutes to wrap up. I sometimes pass out rolling pins, cookie cutters, plastic spoons or forks or bowls, etc. to use while playing with the flubber, but they have just as much fun if I don’t.
This time, I was curious about the school glue vs. multipurpose glue. We had loads of school glue on hand and were running out of the multipurpose, so I tried it out to see how much difference it makes. The school glue flubber was a little less flexible than the one made with multipurpose glue, and wasn’t as much fun to play with. I handed out a little bit to each table so they could try it out.
In the last 5 minutes, I hand out Ziploc bags and remind them to keep the flubber airtight so it doesn’t dry out. Then we talk about how flubber is like a solid and how it is like a liquid. If there are older kids, I might talk a little bit about Newton and how he wrote lots of scientific descriptions about the way the world works. His definition of fluids doesn’t work for things like flubber, so we can call them “Non-Newtonian fluids”. I show them the Flubber Instructions handout and point out where it tells them that flubber can be removed from carpet, clothing, hair etc. with white vinegar. I hope that’s true – my original recipe says so, but I’ve never had to try it out. Then I release them back into the world with bags of flubber. It’s a fun 45 minutes!