Science Craft: Rubber Blubber

Our first science experiment/craft of our Fizz Boom Read! Summer Reading Program for grades 1-6 featured Rubber Blubber (aka Homemade Gak). I found a number of recipes online, and settled on this one from Erika. I did a bit of unit conversion (my algebra teacher hubby would be proud!) to come up with how much supplies I would need for the 100 kids we expected to come through that day.

I figured I would need 2/3 cup Borax in a gallon of water, to
make the "Borax solution" ahead of time for 100+ "servings".

I set up the craft in a buffet-style format, along two counters so we could have two lines going at once. Instructions were everywhere with how much of each ingredient to place in their bag. Then the kids went to a table and started squishing their bag!

My sample, which I took out every so often to show.

 Each kid would use:

• 1 plastic baggie (I used quart sized freezer bags, so they would be sturdy enough for all the squishing)
• 4 spoonfuls of water
• 2 drops of food coloring (neon colors are great!)
• 4 spoonfuls of glue (I went through about a gallon of Elmer's School Glue, but didn't have nearly as many kids as we'd hoped for)
• 2 spoonfuls of Borax solution

Spoonfuls was a really easy measuring system. I just made sure to keep the proportions correct from the recipe. The glue was the hardest to measure, and I often ended up adding another spoonful after kids had squished for awhile.

They never believed me when I said they needed to squish for over 5 minutes! :) My last instruction on the paper said "Even when you think you're done, MIX MORE!" I had food coloring stains on my hands that I showed them, from trying to take my blubber out of the bag before it was mixed all the way.

This craft was such a huge hit. Unfortunately there was also a day camp going on at one of the local schools that took a lot of my kids away. Parents came in saying their children were so disappointed they couldn't come, and did I have the recipe I could share? So I posted the link above to our Facebook page, and directed parents there so they could make it themselves.

I wish Borax came in smaller containers. Oh well, I bought this box myself and am using the rest at home with my laundry. :)