Ready for more colour changing magic? We’ve done some fun experiments involving colour changing Oobleck, including one that changed colour with chemistry and one that magically changed colour due to heat. Once we played with that heat sensitive Oobleck we immediately had ideas for future projects. Today we are tackling the first one, Magic Playdough that changes colour as you play with it. Sound like fun? Well it was!
Learn How To Make Magic Playdough
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Playdough is the original sensory play item. So many people grew up playing with this squishy fun substance. Playing with it helps build fine motor skills and fosters creativity and imagination. Plus it is so much fun!
It is only recently that I started making my own playdough at home, but once I started and realized how easy it is to make, I wanted to make more and more. And get creative with our playdough recipes.
Really that’s what we do around here. We get creative and experiment! Sure sometimes we fail but more often than not we come up with the most amazing, fun creations.
This new Playdough Recipe qualifies as a HUGE success… with one minor fail. Read on to learn more!
How Does Magic Colour Changing Playdough Work?
With this recipe we are using a thermochromatic pigment to create our magical colour changing playdough.
What does this mean? It means this playdough recipe is heat sensitive. The more you play with it the more it changes colours!
We used 3 Thermochromatic Pigments when making our playdough. One changed from red to yellow. Another black to green. The last blue to violet.
OK, like all of our projects we want to dig into some of the “whys” and understand the science behind our projects. We want to foster curiosity and we do that by learning the science so we can answer all of those questions. Which often spin off into new creative projects!
First let’s look at the science behind playdough
In this playdough recipe, the dry ingredients, salt, flour and cream of tartar are physically combined to produce a ‘mixture.’ This means they are combined without any chemical reaction occurring.
When the liquid ingredients water, and baby or vegetable oil are mixed with the dry ingredients, they form what’s called a ‘solution.’ Cooking these ingredients (applying heat) creates a chemical change to the solution and a new ‘substance’, our playdough, is formed.
In any recipe, every ingredient has a purpose. If it didn’t have a purpose, you wouldn’t be using it. The way those ingredients interact involves some fascinating science as we make our playdough.
Flour contains proteins that, when mixed with water, change their shape and become more stretched. We learned about this in our bread science lesson.
Salt allows this structure to hold its shape and also acts as a preservative which helps prevent the playdough from going bad.
Oil provides moisture so our playdough is soft and pliable. We used Baby Oil in this recipe because I had a lot of it on hand to use up. This could easily be replaced 1:1 with vegetable oil or coconut oil.
Cream of Tartar helps with elasticity and is another preservative.
The science of Thermochromatic Pigment
When a substance changes colour due to temperature changes we say it is Thermochromic. This comes from the Greek words thermos (heat) and chroma (color). My word origin loving kids thinks this kind of fact is brilliant!
Thermochromic pigments use liquid crystals or leucodye technology. Leucodyes are organic (carbon-based) chemicals that change color when heat energy makes their molecules shift back and forth between two subtly differently molecular structures. These different structures cause the pigment to absorb and reflect light at different wavelengths. This results in the pigment being one of two different colours depending on the temperature.
This brings us to a very important lesson. Pick your thermochromatic pigment carefully.
Some of them have VERY high change values. This is the point where the colour changes. For this experiment I used three pigments that had change values of either 22 C (72 F) or 25C (77 F). We have Black – Yellow, Red – Yellow and Blue – Violet.
Magic Playdough Ingredients & Supplies
1 cup flour
1/2 cup salt
2 tablespoons cream of tartar
1 cup water
2 tablespoons baby oil (vegetable or coconut oil works too)
Measuring Cups and Spoons
How To Make Heat Sensitive Colour Changing Playdough
Mix the dry ingredients – Add the flour, salt and cream of tartar to a medium mixing bowl. Stir to combine.
Boil the liquids – Add the water and oil to a medium saucepan. Bring to a boil and remove from heat.
Mix wet and dry ingredients – Slowly pour the flour mixture into the hot water. Stir constantly until a stiff ball of dough forms (this takes about 3 minutes). Let cool for a minute.
Knead until playdough is soft and pliable – Remove the dough from the saucepan and place on your work center. Knead the dough with your fingers for about 2-3 minutes or until soft and pliable.
Colour the playdough with Thermochromatic Pigments – To make three different colour changing combinations, divide the playdough into three sections. Shape the playdough so it has a little hole in the middle. Into each ball of playdough add a teaspoon of thermochromatic pigment. Carefully knead until the pigment is completely mixed in. Repeat with each of the pigment colours.
Store in an airtight container for up to one month.
Playing with Colour Changing Playdough
We were really excited to play with our playdough and it was still a little warm from making it. So we placed it in the fridge to cool it off. We knew it was ready when our playdough turned Red, Black and Blue. It was time to play!
Tip! Don’t leave the playdough in the fridge too long. It holds the coolness and you might struggle getting it to be heat sensitive because the dough is just so cold. Room temperature or slightly cooler is best depending on your pigments.
As you knead and create and play with your magic playdough it will start to change colour! Our red dough turned yellow, our black dough turned green and our blue playdough… stayed blue.
Remember I mentioned earlier that we did have a fail with this experiment? Well this was our fail. For some reason we could not get this particular colour to change. I am still not entirely sure why. I think perhaps the blue and violet are so close in colour that we couldn’t really see the colour changes in the playdough medium. It simply wasn’t dynamic enough. However, you could see it clearly in our Magic Colour Changing Oobleck. So we are a little stumped on this one. But we will play more and see if we can figure out why it wasn’t working. That’s what experimenting is all about!
Up your play value by using a chilled can as a rolling pin, or shape the playdough around a warm mug to see what happens to the colour. Take your playdough outside on a hot day after letting it sit in the fridge for a bit to see some dynamic and drastic colour changes. Or if you live somewhere cold, take your playdough from the warm house out into the cold.
Most of all experiment and have fun!