Photos courtesy of Amy Holcomb

IT’S SQUISHY, STICKY, SMOOTH, AND IRRESISTIBLE. Kids love making and handling slime—a soft, malleable substance similar to Play-Doh, but stickier and stretchier. Slime is also a fine hands-on chemistry experiment and easily made in the library or classroom using common products.

At the Skokie (IL) Public Library, where I’m the experiential learning supervisor, we’ve made slime in informal learning environments, including the BOOMbox, our library’s STEAM space, for kids in grades 3–8. Making slime is collaborative, messy fun—plus, kids can take it home.

Supplies

Borax (or a borax substitute) Clear or white school glue Warm water Food coloring Plastic spoons Measuring cups or plastic cups (16 oz) Protective eyewear (optional though recommended) Gloves (optional) Quick access to sink with soap

Prepare

Borax, or sodium borate, is a common ingredient in products such as saline solution. Some people have sensitivities to boron-containing products. While borax is a great slime activator, there are alternatives if you are concerned about allergic reactions. These include liquid laundry detergent, cornstarch, shaving cream, and gelatin. Visit the website “Little Bins for Little Hands” for alternative slime recipes (bit.ly/2GmOpVy).

Before getting started, remind students that this is a chemistry experiment and review safety precautions: Don’t touch eyes or others, avoid spilling ingredients that may cause slipping hazards, and wash hands afterward. Lab goggles are recommended; users may also don plastic gloves, aprons, or lab coats.

Gather the necessary supplies. It’s helpful to have multiple containers of water, glue, and borax for smaller groups or pairs of students to share. Have copies of the recipe and instructions on the work tables in protective plastic sleeves, and post a large version.

Create

Combine equal parts liquid glue and water in a measuring cup or plastic cup. Try starting with 1/4 or 1/2 cup of each ingredient. Stir in food coloring for desired color.

In a separate cup, combine one teaspoon borax with about 1/2 cup warm water. Stir until the borax is dissolved. Add the borax solution a little at a time to the glue solution, stirring thoroughly. When it becomes too hard to stir, remove the slime formation and knead with your hands until it reaches the desired consistency or texture. You may not use all of the borax solution, or you may need more, depending on how sticky the result is. Experiment until you reach the desired consistency.

Place the slime in a clean cup or container, clean the workspaces, and wash your hands. Also, wash hands after manipulating slime.

As students are playing, you can share information about the chemical process. Borax is made of borate ions that react with PVA—polyvinyl acetate—in liquid glue. The PVA in glue is responsible for the polymer chains, or linked molecules, that give glue a stretchiness in its liquid state. When PVA combines with borax along with water, the polymers, or chains, thicken and lengthen, resulting in a stretchy, slimy material—slime!

Extensions

Experiment with different types and amounts of ingredients. Our students tested Mod Podge in place of glue. They compared the ingredients in liquid glue and Mod Podge and hypothesized which ingredient is necessary for slime production.

Experiment with the order of the recipe to see which reactions need to occur in which order for optimal results.

Add glitter or sequins to the mixture for a dazzling effect.

Amy Holcomb is the experiential learning supervisor at Skokie (IL) Public Library.