When I was growing up, mood rings were the trending accessory. If your ring changed color, who knows what mood you were actually in but it must have meant your mood changed, right? Come to find out years later the color changing effects were just temperature dependent. Not quite as exciting, but still mesmerizing! So why not try to make a color changing "mood" slime? This tutorial will guide you through the steps of making your very own thermochromic slime and explore the fascinating science behind its color-changing properties. Let's dive in!
Understanding the Color Change
The secret behind the color-changing effect in thermochromic slime lies in a special ingredient called thermochromic pigment. This pigment contains tiny microcapsules that are filled with temperature-sensitive dyes. These dyes undergo a reversible color change based on temperature fluctuations. When the slime is exposed to heat, such as from your body or warm air, the temperature-sensitive dyes react, causing the slime to shift in color. It's like having a little chemistry experiment in the palm of your hands!
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!
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You will need:
1/2 cup white or clear Elmer's glue
1/2 cup warm water
1/2 teaspoon baking soda
About 1 teaspoon thermochromic pigment
Optional: 1/2 T clear dish soap*
1 T saline solution (not contact solution)
Step 1: Let’s Get Started
Pour 1/2 cup of 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. Add in about 1 teaspoon of thermochromic pigment of choice. Mix together until uniform. When you are choosing your thermochromic powder, pay attention to the temperature at which it's activated. This selection of powders give beautiful color options, but note that the color doesn't change until it reaches 88 degrees Fahrenheit. It's not necessarily a bad thing, but you have to work for the color change a little harder!
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: Experiment with color changing effects
You have made color changing slime! Enjoy the slime as is or feel free to add in more pigment or other color changing 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. The color-changing effect may diminish over time with repeated use, but you can reactivate the thermochromic properties by applying heat again.
*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 color changing slime!
Making color changing slime with thermochromic pigment is a fantastic way to engage in sensory play and have some fun with science. Try different techniques to get the slime to change color. Can your hands or breath warm it up enough? What happens when you blow warm air on it with a hair dryer? Enjoy experimenting all the ways you can play with "mood" slime!
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