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Classic slime recipe: The best method for a longer lasting stretch


Going back to the basics is sometimes the best option. There are so many great slime recipes out there to try, but making a classic slime recipe will never disappoint. This classic slime recipe provides a fantastic sensory activity that will entertain for hours. The best part about it is that it can last for weeks if properly stored between playing. I've found that slime can lose some of it's stretch after a few days, but I have discovered a trick that can keep it feeling fresh for longer. The secret is dish soap! While it's not a necessary ingredient, adding a small amount of dish soap helps this classic slime keep it's stretch for longer, allowing kids to continue enjoying the slimy sensation.


The Science of Slime


Did you know that slime is created by a fascinating chemical reaction? Understanding the science behind slime-making can add an extra layer of excitement to kids' slime-making activities. Let's take a closer look at how this transformation unfolds.


The primary ingredient responsible for slime's texture is a polymer called polyvinyl acetate (PVA), found in common school glue. When you mix the glue with a slime activator, usually a liquid containing borate ions like borax, saline solution, or liquid starch, a unique chemical reaction occurs.


During the mixing process, the borate ions in the activator solution crosslink the polymer chains in the glue, creating a network of long, interconnected strands. This process is known as crosslinking polymerization. As a result, the once runny and liquid glue transforms into a stretchy, semi-solid substance we know as slime.


The crosslinks between the polymer chains give slime its unique properties. When pressure is applied to slime, these crosslinks allow the material to stretch and deform. However, when the pressure is released, the crosslinks pull the material back together, giving slime its ability to return to its original shape.


But what makes slime feel slimy? It's all about the water. Slime is a non-Newtonian fluid, which means its viscosity and flow properties change depending on the applied force. The glue in slime contains water, and as you mix in the activator, it helps trap the water molecules between the polymer chains. This water contributes to the slippery and slimy sensation when you touch or play with slime.


As your kids make slime, encourage them to observe the changes that occur during the mixing process. Discuss the transformation of the glue from a liquid state to a slimy substance, and the role the activator plays in facilitating the chemical reaction. By understanding the science behind slime, your children can gain a deeper appreciation for the chemistry.


Remember, safety is key when conducting any science experiment. Always ensure adult supervision. Some slime recipes use potentially hazardous ingredients like borax, so always opt for safer alternatives such as saline solution or liquid starch.


So, as you dive into slime-making, explore the chemical reactions at play, and nurture the curiosity and scientific inquiry of your little ones. Let the exploration begin, and may your slime adventures be as educational as they are enjoyable!

 

This post contains affiliate links, meaning I will earn a small commission if you purchase through these links at no cost to you.

 

You will need:

Step 1: Let’s Get Started


Pour 1/2 cup of white Elmer's glue into a mixing bowl. Wash off excess glue from measuring tools before it has a chance to dry.


Step 2: Prepare the water

Add 1/2 cup of warm water to a measuring cup. Measure out 1/2 teaspoon of baking soda and mix in the warm water until fully dissolved. Next, slowly mix in 1/2 Tablespoon of dish soap until the mixture is uniform. Don't whisk too quickly here or you'll introduce foam from the soap.


Step 3: Combine ingredients

Slowly pour the warm water with dissolved baking soda and dish soap into the bowl with the glue. Mix together until uniform. This is also a great time to mix in your dye. Regular food coloring works, but I also really like this product for slime. Add a couple drops for a mellow pastel, or more to achieve a brighter, vibrant color.


Step 4: Add the activator

Measure out 1 Tablespoon of saline solution. It's important to use saline solution rather than contact solution, because it has a higher concentration of boric acid and sodium borate. Contact solution would likely require a larger volume. Slowly pour the saline solution into your glue mixture while briskly stirring. The mixture will start to gel immediately as the saline solution reacts with the glue to form the polymer.


Step 5: Mix and knead

After the saline solution has been added, continue mixing. The slime will be very sticky at this point. Once it starts lifting from the sides of the bowl, you can start kneading it thoroughly with your hands. It will still be very sticky! Stretch and mix together for 5-10 min until the slime gets firmer and less sticky. If after 10 minutes the slime is still not to your desired consistency, then add a little more saline solution. But remember, adding too much will make your slime too hard. I recommend only adding an additional teaspoon at a time followed by 5 minutes of mixing before deciding to add more.


Step 5: Store in airtight container

You have made slime! Enjoy the slime as is or feel free to add in more color or other add-ins at this point. After you are finished playing with the slime, but sure to store it in an airtight container. If you keep it clean and store it properly it can last for several weeks.


*Note about the dish soap

The dish soap is not a necessary ingredient, but I have found it adds extra stretch which I like. However it will introduce more air and make the slime cloudier initially. It will also take more time to clear out the bubbles when adding soap.

 

Enjoy your classic slime!

Slime is a fantastic activity to do with your kids. This classic slime can be played with as is, or you can add extra ingredients for even more sensory fun. Try using this slime as a base to add a generous amount of glitter, sequins, or beads. Adding in dye to white slime tones down the color compared to clear slime, so add in extra dye for a more vibrant color. I've had a lot of luck using dye made specifically for slime, I've found that it washes off hands more easily than regular food coloring. Plus it comes in a wide range of beautiful colors. The possibilities are endless. Enjoy your slimy creations!

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Meet Jamie

A scientist with a passion for creating engaging kids' STEAM activities to foster a life-long love for learning. Learn more about the author >> 

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