Making slime is something you might remember from science class as a kid, or maybe as a fun activity during summer camp. Learning how to make slime is a fun and simple process and can serve as an educational way to have fun with the kids. It can also be a useful teaching tool for the younger grades just learning about the scientific process and how to follow laboratory instructions. Whatever your interest, keep reading to learn the science behind slime and the supplies and instructions for how to make slime.
What Is Slime?
Photo credit by: time.com
Slime is most fondly remembered as that goopy messy blob, not quite a liquid but not quite a solid, and colored any shade of food coloring you had on hand. It’s often made from glue and borax or sometimes starch and is unequivocally a messy project. The unifying thing about slimes is how they act when you hold and touch them. Learning how to make slime can inspire creativity and curiosity in nearly anyone.
Slimes fall under the classification of non-Newtonian fluids which means that sometimes they act like a solid and at other times like a liquid. We’ll go into the science later, but when you take a ball of slime and throw it against the table, it seems to solidify and hold together—not what you would expect a liquid to do. However, if you were to pour slime out of the bowl you made it in, it would run more like a liquid, not at all like a solid.
The reason for this behavior is the chemical makeup of the slime, which stays fairly consistent between the different methods of how to make slime. We’ll be going through three different methods for how to make slime.
How to Make Slime The Classic Way
This first slime is most likely the one you made or saw as a kid. For this, we are going to need the following:
- Sodium tetraborate (Borax)
- Craft glue
- Food coloring (optional)
This method of learning how to make slime is fairly simple. Borax is easy to find at most grocery stores and any school glue should work well. Of course, food coloring isn’t necessary for the chemistry to take place, but it does add to the visual appeal of the slime and makes the process that much more fun.
- 1Measure out about 1 ounce of glue into a bowl and mix it with a quarter cup of water: add food coloring to the glue/water mixture if you would like
- 2Add a quarter cup of Sodium Tetraborate (Borax) Solution to the glue/water and stir
- 3Continue to add Borax solution until it gets tough to stir; then knead the mixture until it is no longer sticky
- 4Make sure the compound is thoroughly mixed, kneading as long as necessary
- 5Discard any residual water or leftover solutions
The lump you have in front of you is a full-fledged slime. Be sure to bag it up and refrigerate it if you plan to keep it overnight or for several days. Mold will begin to grow if it is left at room temperature for too long.
How to Make Oobleck
Oobleck, as it is affectionately called, is one of the more dramatic quality of slimes. This one is much runnier and messy than the last, but more starkly demonstrates the non-Newtonia properties of slime and is ideal for science presentations. “Oobleck” is a reference to the Dr. Seuss book Bartholomew and the Ooblek where a large blob named the Ooblek threatens the Kingdom of Didd. Of course, our Ooblek won’t be sentient, but it can cause quite a mess.
For Ooblek, we are going to the need the following:
Be sure the bowl is quite large and sturdy. Ooblek cannot really be carried around or left on a table like other slimes.
- 1In the large bowl, mix the water and cornstarch together in small increments
- 2Mix until the consistency is that of honey and it looks like buttermilk
- 3Keep the ratio of cornstarch to water at about 2 parts cornstarch to 1 part water: 16 ounces of cornstarch should take roughly 1.5 cups of water
- 4Make sure to start with less water and gradually add more until you reach the desired consistency
- 5If too watery, add more cornstarch to balance it out
This is the fun part, or perhaps the part where you call up a student to try out the mixture. When you run your hand slowly through the mixture, you should feel very little resistance, like moving through a liquid. If you speed up, you’ll begin to feel more drag. If you used a large enough bowl, dip your whole hand in and try to grab and release the mixture or try slapping the top of the mixture. The mixture should tense up at times and seems to harden, to fall apart, or to dissolve back into a liquid. This can be a great time to ask for observations and suggestions for explanations as to why this phenomenon is occurring.
Obviously, stay safe in all this, and if the mixture seems to be flying everywhere, you probably added too much water and need to re-balance with more cornstarch.
How to Make Movie Slime
If you’ve seen that boiling green vat of radioactive liquid in the movies or goopy alien blood in a sci-fi flick or even flubber, that’s what we’re aiming for with this recipe. Obviously, Hollywood has more at its disposal in the effects department than we have in our kitchen, but this is a pretty good re-creation of it. This one does require PVA (polyvinyl alcohol) which you can get from chemical supply locations or online. It is non-toxic, but it should still be kept away from young children (which is true of all slimes, none of these recipes are for eating).
For this one, we will need:
- Glass container (beaker or jar)
- Food coloring (optional)
- 1Using your glass container, add a half cup of the PVA and any food coloring you wanted to use
- 2Use a stick or stir rod to mix thoroughly
- 3Slowly add 2 tsps of the Sodium Tetraborate Solution (Borax) to the PVA solution
- 4Stir until the mixture reaches a uniform consistency
Keep the slime in a jar or bag and refrigerated when not in use. Do not eat the slime. Be sure to wash hands thoroughly after making and playing with the slime. This slime should act and feel much like the first recipe. You can keep it out on a table top and throw it around and notice how the consistency changes. The only difference is this slime should be clear and gooey.
Using Slime to Teach Science
For many of the parents out there, this can just be a fun way to demonstrate how to make slime and follow a recipe with a cool payoff at the end. However, for the more educationally minded individuals, you may be wondering why exactly slime behaves the way it does.
The classic slime is made with regular craft glue which contains long polymers called polyvinyl acetate. These long chains act a bonding points for the borax which results in huge polymers, which in turn gives the slime its putty-like texture. The more you move it around and apply pressure, the stiffer it gets. The movie slime is similar although the base polymer is different. In both cases, hydrogen bonding is taking place throughout the mixture and this incidence of this is affected by the movement you impart on the mixture. That’s why if you let it sit and relax, it will gradually turn more liquid and spread out.
The Ooblek is a bit more complicated, but it functions more as a true non-Newtonian fluid. While Newtonian fluids like water or honey have a viscosity dependent on the temperature of the surroundings and pressure of the fluid itself, non-Newtonian fluids are also affected by the pressure applied to the fluid from outside sources. You wouldn’t expect water to tense up if you threw it against a wall or if you punched a bowl of it, but Ooblek does just this. It behaves in much the way that quicksand does. Other non-Newtonian fluids include ketchup, Silly Putty, and caramel topping.
Learning how to make slime can be a fun and educational way to spend a class or an afternoon. It’s easy to integrate all the skills needed to succeed in higher level science laboratory classes: supplies checklist, following instructions closely, recording results and observations, and staying safe with some relatively benign ingredients. Ooblek in particular, but any of the slimes, make for a wonderful spectacle and a way to get kids wrapped up in the fun side of science. Even in the home, kids can make slime as a great favor at parties or just a cheap toy for the day. Either way, just be prepared for the mess!