Tie a cloth and dye it using colorful chemical reactions!
- Put on protective gloves and eyewear.
- Conduct the experiment on the plastic tray.
- Do not allow chemicals to come into contact with the eyes or mouth.
- Keep young children, animals and those not wearing eye protection away from the experimental area.
- Store this experimental set out of reach of children under 12 years of age.
- Clean all equipment after use.
- Make sure that all containers are fully closed and properly stored after use.
- Ensure that all empty containers are disposed of properly.
- Do not use any equipment which has not been supplied with the set or recommended in the instructions for use.
- Do not replace foodstuffs in original container. Dispose of immediately.
- In case of eye contact: Wash out eye with plenty of water, holding eye open if necessary. Seek immediate medical advice.
- If swallowed: Wash out mouth with water, drink some fresh water. Do not induce vomiting. Seek immediate medical advice.
- In case of inhalation: Remove person to fresh air.
- In case of skin contact and burns: Wash affected area with plenty of water for at least 10 minutes.
- In case of doubt, seek medical advice without delay. Take the chemical and its container with you.
- In case of injury always seek medical advice.
- The incorrect use of chemicals can cause injury and damage to health. Only carry out those experiments which are listed in the instructions.
- This experimental set is for use only by children over 12 years.
- Because children’s abilities vary so much, even within age groups, supervising adults should exercise discretion as to which experiments are suitable and safe for them. The instructions should enable supervisors to assess any experiment to establish its suitability for a particular child.
- The supervising adult should discuss the warnings and safety information with the child or children before commencing the experiments. Particular attention should be paid to the safe handling of acids, alkalis and flammable liquids.
- The area surrounding the experiment should be kept clear of any obstructions and away from the storage of food. It should be well lit and ventilated and close to a water supply. A solid table with a heat resistant top should be provided
- Substances in non-reclosable packaging should be used up (completely) during the course of one experiment, i.e. after opening the package.
FAQ and troubleshooting
It’s cotton — a natural material you probably interact with every day.
We recommend trying this experiment with a piece of cloth from the set first. But in general, just make sure that any cloth you want to use is really okay to use in this experiment – you won’t be able to wash the colors out later!
See for yourself! Don't be afraid to experiment!
Place the cloth on a flat surface. Place a wooden stick in the center and press it tightly to the surface. Start twisting, guiding with your hand. If this doesn't work, ask an adult for help.
Yes, of course! If you want, you can use just one or two colorings (for instance, you can use just curcumin and chlorophyllin). Apply them any way you want. Of course, your results will differ slightly from those shown in the instructions.
This is likely because the cloth wasn’t wet enough, or perhaps not enough dye was applied during the process. This isn’t a problem at all – you can either use a new piece of cloth or repeat the experiment with this one.
Be sure to wear protective gloves and perform the experiment on the tray. It's always a good practice to do so, but when you work with colorings things can get especially messy.
Soak a piece of cloth in water.
Twist and secure the cloth.
Apply some potassium hexacyanoferrate(III) K3[Fe(CN)6] to the cloth.
Both iron(II) sulfate FeSO4 and copper sulfate CuSO4 react with potassium hexacyanoferrate(III) K3[Fe(CN)6] to form vibrantly colored compounds: Fe3[Fe(CN)6]2 and Cu3[Fe(CN)6]2.
Both Fe3[Fe(CN)6]2 and Cu3[Fe(CN)6]2 are insoluble in water, so they stay in between the cloth fibers even when you wash the cloth. Such vibrantly-colored insoluble substances used to color materials are called pigments.
Cloth can also be dyed using readily soluble compounds. To dye the cloth effectively these compounds must form some kind of chemical bond with the cloth itself, so water can't easily wash them away. Many food colorings, such as curcumin, chlorophyllin and anthocyanin, can form such bonds with the cellulose, the compound your cloth is mostly made of. Soluble colorings like these are called dyes.
Dispose of solid waste together with household garbage. Pour solutions down the sink and wash with an excess of water.
How do we dye the cloth?
We use the following reagents as dyes: potassium ferricyanide K3[Fe(CN)6] solution, iron(II) sulfate FeSO4 solution, and copper sulfate CuSO4 solution. These compounds won't leave an intense color on a piece of cloth, and can be easily washed away. But if you first apply potassium ferricyanide K3[Fe(CN)6] solution, and then the other two compounds, the cloth will stay a striking bright blue and brown! This happens due to the formation of new insoluble compounds.
When the potassium ferricyanide K3[Fe(CN)6] solution reacts with the iron(II) sulfate FeSO4 solution, a blue insoluble pigment is formed. It is known as Prussian blue, which has a long history of use as a blue pigment. It is also called Berlin blue, Parisian blue, or Paris blue. It resists atmospheric influences, light, and acids, but is easily destroyed by the weakest alkalis. Therefore, Prussian blue has limited practical applications nowadays — it is used, for example, to obtain printing ink and blue carbon paper, and to tint colorless polymers such as polyethylene.
The brown color is caused by the formation of poorly-soluble copper ferricyanide.
How does this method work?
The piece of cloth is twisted using a stick in order to create its special spiral-like pattern. The tighter the cloth is twisted, the better the pattern will be — the lines will be straight and neat. We have to wet the cloth to help the dyes spread more easily. Moreover, it helps smooth the transition from color to color. If you don’t wet the cloth well, you will see clear white borders between the colored spirals.
This technique is known as “tie-dye.” It is rather old; the earliest known example of such a technique is dated to the second half of the first millennium (500–800 AD). This method was very popular in the 1960s.
To conduct this experiment, prepare a piece of cotton fabric as you did earlier. Soak it in water, squeeze out any excess water, twist it into a bundle, and secure it with two rubber bands. Don’t forget to place the bundle in a Petri dish and set it on the tray!
As you know, this time you’ll use dyes: curcumin, anthocyanin, and chlorophyllin. The fabric should be soaked with dye. Apply the chlorophyllin solution in a criss-cross pattern. Apply the anthocyanin solution to one free section of the bundle, and curcumin solution to the remaining section. Turn the bundle over and apply the dyes to the other side as well. Leave undisturbed for 1 hour to let the dyes set in the fabric.
Now, remove the rubber bands. Wash the fabric thoroughly with water. Check out the result! If you want, you can experiment to make other patterns too. Just apply the dyes to a new piece of fabric in a different sequence and observe the new result!
What happened in this experiment may seem straightforward: dyes are going to dye, after all. But how do they do what they do? In other words, why do dyes stick to cloth? As it turns out, dye molecules tend to form bonds with the molecules that cloth fibers are made of. But not every dye sticks to every type of cloth. Cotton is mainly cellulose , and many food colorings stick to it quite well. Wool and silk, on the other hand, are mainly proteins and “like” to keep other types of dyes by their side. Next time you accidentally stain your clothes and can’t wash it off, don’t blame yourself—it’s chemistry’s fault!
Why do the colors stay on the cloth?
This piece of cloth is made of cotton — a natural material consisting mostly of cellulose. The coloring particles in our experiment form directly in the fabric fibers, precipitating there and getting stuck. As these substances are practically insoluble in water, they’re very difficult to wash out. Such colorings are called pigments. As you can see, natural food dyes also stick to cotton quite well! In fact, they can chemically interact with the fibers, attaching to a piece of cloth via hydrogen bonds.