If you find yourself scratching your head with the latest slime obsession, keep in mind that making slime is actually science! Slime is chemistry! Polymers and non-Newtonian fluids can be a little confusing for young kids, but our short lesson in the science of slime below is a perfect way to answer the question, is slime a solid or liquid? We LOVE homemade slime!
Making Slime With Kids
Making and playing with slime has proven highly fascinating for kids and adults of all ages, but you might not be familiar with basic slime science. Have curious kids who want to know why slime is liquid and a solid?
Basic slime science is great to share with kids who love slime because it’s an excellent learning opportunity already built into an enjoyable hands-on activity.
First, have you ever made an excellent homemade slime with your kids? If you haven’t (or even if you have), check out our collection of the BEST HOMEMADE SLIME RECIPES. Several slime recipes are the foundation for all our slime variations.
Helpful Slime Resources To Get You Started
Everything you need to know about making slime is below! Did you know we also have fun with science activities too?
What Is Slime?
The best glue is a PVA (polyvinyl-acetate) washable school glue.
You have several slime activators (all in the boron family). These include:
- saline solution
- liquid starch
- borax powder
These slime ingredients or slime activators all contain similar chemicals for making a slime substance. Cross-linking is what happens when the glue and activator are combined!
Is Slime A Liquid Or A Solid?
Slime involves chemistry! Chemistry is all about states of matter, including liquids, solids, and gases. It is all about how different materials are put together and made up of atoms and molecules. Additionally, chemistry is how these materials act under different conditions.
Slime is a non-Newtonian fluid. A non-Newtonian fluid is neither liquid nor a solid. It can be picked up like a solid but also ooze like a liquid.
Our 2 ingredient oobleck is another example of a non-Newtonian fluid!
You will notice that slime has no specific shape and will change it to fill whatever container it’s placed in. However, it can also be bounced like a ball because of its elasticity.
Slime is an example of Shear-thickening fluids or fluids in which stress causes an increase in viscosity. When shear stress, such as quickly stirring or pulling the slime apart, the slime shears or breaks. Pull the slime slowly, and it flows more freely. If you pull it quickly, the slime will break off more easily because you break apart the chemical bonds.
What Makes Slime Stretchy?
Slime is all about polymers! A polymer is made up of very large chains of molecules. The glue used in slime comprises long chains of polyvinyl acetate molecules (that’s why we recommend PVA glue). These chains slide past one another fairly easily, that keeps the glue flowing.
Chemical bonds are formed when you mix the PVA glue and slime activator together. Slime activators (borax, saline solution, or liquid starch) change the position of the molecules in the glue in a process called cross-linking! A chemical reaction occurs between the glue and the borate ions, and slime forms the new substance.
Instead of flowing freely as before, the molecules in the slime have become tangled and create what is slime. Think wet, freshly cooked spaghetti versus leftover cooked spaghetti! Cross-linking changes the viscosity or flow of the new substance.
Slime Science Project
You can experiment with the viscosity or thickness of slime using our basic slime recipes. Can you change the viscosity of slime with the amount of slime activator you use? We show you how to set up your own slime science experiments in the link below.
Can You Make Slime Without Borax?
Concerned that borax is not good for you? We have several taste-safe borax-free slime recipes for you to try. Find out what fun substitutes for borax you can make slime with! Please note that a borax-free slime will not have the same texture or stretch as traditional slime.
Slime Recipes To Try
We also have the most popular recipes kids want to be making right now, like crunchy slime, butter slime, and cloud slime (to name a few)!
Click on the photos below to see all the kinds of slimy resources available. Get our ultimate slime-making pack to download and print!
All the best homemade slime recipes in one place with plenty of fantastic extras! Plus, it includes a slime science guide!
Includes a Slime Science Project Pack!
- The Ultimate Slime Guide contains all the specialty recipes you or your kids want to make! You’ll find all the best tips, tricks, hints, and slime-y info in almost 100 pages!
- The Ultimate Slime Holiday Guide covers all the best holidays and seasons with special themes and slime-y projects!
- The Ultimate Borax-FREE and Taste-Safe Slime Guide shows you how to make all the best borax-free, taste-safe, and non-toxic slimes kids love, such as marshmallow slime. These recipes do not use chemical activators such as saline solution, liquid starch, or borax powder, making them truly borax-free.
- The Ultimate Slime Coloring Book is an easy-to-print coloring book kids will love! Color and design your favorite slimes!
- The Slime Starter Guide is a fact-filled information guide with everything you need to know to make the best slime ever!
- Slime Science Project Pack helps you turn slime-making into a science lesson!