Dye a cloth using food colorings!
- 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
This is likely because the cloth wasn’t wet enough, or 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.
It’s cotton – a natural material you probably interact with every day.
See for yourself! Learn more about different materials in the Scientific Description of this experiment.
Prepare a piece of cotton cloth for dyeing.
Apply some dyes to the cloth.
Wash out the excess dye and enjoy.
You can make colors more vivid by rinsing the cloth with an acidic solution.
Dispose of solid waste together with household garbage. Pour solutions down the sink. Wash with an excess of water.
Why do the colorings stay on the cloth?
In essence, we need to understand why the dyes stick to the cloth. Well, dye molecules tend to form bonds with the molecules that cloth fibers are made of.
This piece of cloth is made of cotton - a natural material made up of mostly cellulose.
As it turns out, natural food colorings stick to it quite well! In fact, these substances have some similar fragments that help them interact.
And what about other types of cloth?
Indeed, the chemical composition of the cloth plays a key role. For example, wool and silk are mainly proteins. They differ greatly from the cellulose molecules of cotton cloth. As a result, they prefer to keep other types of dyes by their side.
The same is true for some synthetic materials like polyester. Polyester is made of polymeric molecules of esters. And the dyes we used in our experiment wouldn’t be able to attach to its molecules well.
How can I make an acidic solution?
If you want to make the colors more vivid, soak the cloth in an acidic solution after dyeing it. The easiest way to make an acidic solution is to use the sodium hydrogen sulfate NaHSO4 solution already included in the set (for use in the “Chromatography” experiment).
Measure about 30 drops of NaHSO4 into your beaker. Next, fill the beaker halfway full with water and place the dyed cloth inside. Soak the cloth in this solution for some time. Use a wooden stick or your hands (but make sure to wear protective gloves!). Take the cloth out of the beaker and wash it with clear water. Check out the result!
How does this method work?
The piece of cloth is twisted using a stick in order to create its special spiral-like pattern.
This technique for dyeing cloth is called “tie-dye”. It is rather old; the earliest example of such a technique surviving to the present day is dated to the second half of the first millennium (500-800 AD). These clothes are from Peru, and display vivid red, yellow, blue and green patterns.
This method was very popular in the 1960s.
The wooden stick is the base the pattern is twisted around. The tighter cloth is twisted, the better it will be colored - 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.
These dyes are similar in their origin and application. Curcumin, Chlorofilline, and Anthocyanin are natural dyes, which means they are not synthesized in laboratories, but rather are extracted from natural sources. And all three of them are used in cooking (but make sure not to use the bottles provided for any food-related purposes!).
Anthocyanins are vividly-colored substances that lend plants (mostly their petals) colors from deep purple to bright red. They are water-soluble. Anthocyanins can change their color according to the pH of any given solution (learn more about this with our «Anthocyanins» experiment!). Some edible plants rich in anthocyanins are, for example, the blueberry and raspberry, black rice, and black soybeans. Red rose petals contain a lot of anthocyanins as well. Interestingly, some of the colors of autumn leaves are derived from anthocyanins.
Chlorophyllin is a derivative of the natural green pigment chlorophyll, which is present in almost all plants and seaweeds, and even in some kinds of bacteria! Chlorophyll takes part in the plants' nutrition process: it absorbs energy from the sun and transforms it into the energy required to synthesize the plant’s nutrition. Spinach is likely the vegetable richest in chlorophyll - chlorophyll makes up about 6% of its weight! As it turns out, chlorophyllin is the most common green food coloring in both the EU and USA.
Curcumin is a bright-yellow pigment obtained mostly from turmeric (Curcuma longa), a member of the ginger family. Curcumin has a special aroma and bright color, so it is sold as a cosmetic ingredient, food flavoring, and food coloring. Though it isn’t soluble in ordinary water, it dissolves well in oil, alcohols, and basic media. Just be aware: curcumin fades gradually under direct sunlight, so do not leave your dyed cloth out in the sun!
What kinds of paint are there?
Paint is a common name for a whole subset of coloring compounds prepared specially for household use, i.e. for painting.
Normally, paint consists of:
1) pigments, which are the substances responsible for the paint’s color;
2) adhesives that, upon drying, form a thin film on the surface of a painted object;
3) solvents, which normally evaporate during drying. Solvents keep paint from solidifying too quickly;
4) fillers that play various roles. For instance, there are antibacterial additives or substances that enhance paints’ thermal stability.
Pigments have a certain color because they selectively absorb sunlight: select colors of light are absorbed, while the rest are reflected back into our eyes, causing us to perceive a certain color. For example, if a pigment absorbs violet, blue, green, and yellow light, but reflects the reds, then we will see it as a red pigment.
Adhesives, or filming agents, are substances that form a solid film holding the pigments in place. One of the first filming agents used for fine art painting is egg yolk. It was also used in drawings on the walls of Egyptian pyramids and in icon painting.
Back in the old days, they used egg yolks to dilute certain powdered paints. This procedure yields a product called tempera. Because of the egg yolks, it dries relatively slowly. After drying, tempera becomes waterproof, yet gas- and moisture-permeable. Due to this property, tempera can be reliably used for wall painting: it allows for a smooth, gradual evaporation of the excessive moisture usually left in brick walls after their construction.
Gouache contains yet another unusual component. It is made of pigments, but with the addition of various white paints or kaolin (white clay). Because of these additional components, gouache lightens upon drying, and it can even crack if deposited too thickly.
Solvents dilute paints used for art. Paint is much easier to mix and apply when wet. Once the solvent has evaporated completely, the paint pigments and adhesives solidify, leaving a thin film with a finished image.