It is no secret that polymer chemistry has shaped modern life today. Making borax goo or “gak”, as we at the University of Arizona like to call it, is a fun and easy way to introduce the impact of polymers to our future chemists. Since it is a substance similar to silly putty, we also explain that many polymers are introduced to the market as toys because their serendipitous discovery was not the desired outcome. Additionally, we have our audience identify any polymers that they may see in the room. Often times, we do this demonstration at hands-on workshops where the children are separated into smaller groups by table. These tables and chairs are commonly made of plastic and this allows us to explain that plastics come in different forms. Explaining that different forms of these plastics must be recycled gives our chapter room to promote green chemistry in a general way.
Now for the fun part!
- food coloring (listed first because it is essential)
- Elmer’s glue (we found that Elmer’s works best despite another brand being represented in the figure)
- borax powder
- 3 oz Dixie cups
- spoons or popsicle sticks for mixing
- sandwich-sized plastic bags
Step 1: Dilute your Elmer’s glue. This demo works best if your glue solution is 50% water.
Step 2: Make the borax solution. We usually put about 2 tablespoons of borax powder into 1 cup of water. Often times, we approximate the concentration of our borax solution because in this case, a little goes a long way.
Step 3: Pour the two solutions into separate Dixie cups. When we do this activity for a larger group of people, we set out several of these Dixie cups and only fill them about 1/3 full of each solution so they have room to mix.
Step 4: Now for the critical step: food coloring! Food coloring is a way to make the demo more interactive by allowing each person to pick the color of their gak. Plus, who doesn’t love electric blue slime? Adding the food coloring to the glue portion makes things a little less messy.
Step 5: Slowly pour the borax solution into the glue solution. Mix with a popsicle stick.
We recommend that you store the gak in a plastic bag to prevent the slime from depositing color everywhere– which it will. At least until until it dries. Giving out plastic bags at outreach events should come with a fair warning about gak’s ability to deposit colors…
We have found that gak is a very versatile demo and we love it so much that we even brought it to the Demo Exchange at the National Meeting in San Diego. Gak is a favorite at our Harry Potter themed magic show that we do every October at a local library in Tucson. Turn-out for this event is fantastic and it is awesome to see children get excited about books and science!
Do you have any questions or comments? Let us know!