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Making Bi-coloured Flowers
Published on 24 May 2021

In previous blog post we talked about how to make flower dyes by extracting the pigments from flowers. This time we do just the opposite and demonstrate how to dye a flower with different colours. Following the steps below and let's make a bi-coloured flower together.

1. Add red dye to one container and blue dye to another.

2. Slice the stem of pale coloured flowers – such as roses or carnations – in half lengthwise.

3. Place one half in each of the containers of dyed water.

4. Bi-colour will appear within half a day.


How it works:
1. The dye and water enters the xylem in the flower's stem.
2. The xylem – which acts like a water pipe – transports water throughout the plant.
3. The dyes reach different parts of the petals, creating a bi-coloured effect.


 


 




Natural Dyeing with Flowers
Published on 29 April 2021

The amazing colours of flowers make them a good source of natural dye. Most fabrics used for plant dyeing are natural fibres such as cotton, linen, silk and wool. Silk and wool are animal fibres that contain proteins. This makes the dyeing process more effective as opposed to cotton and linen. Adding a mordant such as potassium alum (aluminium potassium sulfate) can enhance the colouring effect. The mordant acts as a link between the fabric and pigments. This binds the fibre molecules and dye molecules which makes the colours brighter and more long-lasting.

We have tried tie-dyeing cotton fabric with Chinese herbal flowers and tea flowers. Fresh flowers could also be used, but you will need more because of their high water content. Let's look at the natural colours of Safflower, Pagoda Bud, Roselle and Butterfly Pea on cotton and the dyeing procedures.

Materials
Your favourite flowers. For example:
1. Safflower
2. Pagoda Bud
3. Roselle
4. Butterfly Pea
5. Washing powder
6. Potassium alum KAl(SO4)2·12H2O
7. Fabric

Note: The dried flowers should weigh three to five times of the fabric depending on the intensity of colour required.
 

Tools
1. Hot plate
2. Scale
3. Beaker (for making dye solution)
4. Heat resistant container (for dyeing fabric)
5. Filter funnel, filter paper
6. Forceps
7.  Glass rod
8. Wooden sticks, wooden pegs, rubber bands (for making tie-dye patterns)

Note: The containers and utensils used for dyeing should not be used for cooking.
 

Directions
1. Wash the fabric with washing powder and water to remove impurities on the fabric surface. Hang dry.
2. Add potassium alum to water and stir until dissolved. Immerse the fabric in the solution for about 30 minutes. Hang dry.

3. Add the dried flowers to water and bring to boil. Then, simmer for about 30 minutes until the dye solution turns dark. Filter the dye solution.

4. Use wooden sticks, wooden pegs or rubber bands to tie the fabric. The tied area will remain white to create pattern.

5. Immerse the tied fabric in the dye solution completely for about 30 minutes (don't overdo it). Gently flip the fabric over for even colouring. Rinse the fabric with water.

6. Dry the fabric in shade.


 


 





The International Day of Mathematics
Published on 14 March 2021

Today (March 14) is Sunday. Other than being a day off from school and work, today also marks three special occasions: the International Day of Mathematics (IDM), the birthday of Albert Einstein and the death anniversary of Stephen Hawking.

The International Day of Mathematics is derived from Pi Day. Officially announced by UNESCO, the IDM was first celebrated in 2020.

Pi is an irrational number. The numbers in its decimal part would go on forever without repeating. For general application, taking Pi as 3.1416 is sufficient. Currently, the most accurate value of Pi was discovered by the American Timothy Mullicann in 2020. He calculated Pi to a mind-blogging 50 trillion digits. If you read one digit every second, it would take you about 1.58 million years to finish the number!

If it sounds too tedious, how about trying something more light-hearted, like music? If you assign the digits 0 to 9 to musical notes (e.g. 0 to C, 1 to D, and so on), you can turn Pi into a melody. (Click here to listen) Let's dedicate this special music piece in remembrance of the great scientists.





 


How to keep flowers fresh?
Published on 28 February 2021

Flowers are undoubtedly a popular choice to decorate home on festivals, such as the Chinese New Year. However, their beauty only lasts for a few days. Are there any ways to extend the vase life of flowers? Is the specially formulated "flower food" the only way? Interestingly, you can keep flowers fresh simply by adding some things commonly found at home in the water.

First look at the causes lead to flower wilting:

  • 1. Insufficient water
    - The water absorption of fresh flowers is reduced significantly after the roots are severed
    - Bacteria growing in the water causes the blockage of xylem which is responsible for the transportation of water to the flowers
  • 2. Lack of nutrients
  • 3. Ethylene produced by the plants promotes the wilting of the flowers

We have used roses to investigate what to be added to water to keep the flower fresh (taking 1 litre of water as an example)

With water only, the flower cannot last more than a few days.

Best
Adding 1 teaspoon of bleach and 1 teaspoon of sugar OR 2 teaspoons of white vinegar and 2 teaspoons of sugar

The acidity of the vinegar can inhibit bacterial growth and promote water absorption of the flowers, while bleach can kill bacteria. Sugar is added to provide nutrients to the flowers. Both solutions work as good as off-the-shelf flower food which has antiseptic, sugar and acidifier as the main ingredients.

Good
Adding 1/4 can of soft drink

The acidic soft drink can also inhibit bacterial growth and promote water absorption of the flowers. The sugar content of the beverage can be utilized by the flowers. Adding lemon slices or lemon juice will have a similar effect.

Good
Adding 2 teaspoons of 70% alcohol

Besides killing bacteria, alcohol can inhibit the production of ethylene by the plant and slow down wilting. However, adding too much alcohol will kill the plant cells.

Worst
Adding 2 teaspoons of sugar OR 1 teaspoon of salt

While sugar provides nutrients to the flowers, it also boosts bacterial growth in the water. Whereas high concentration of salt inhibits bacterial growth at the expenses of dehydrating the flowers.

Investigation result of the best way to keep flowers fresh
(Click to enlarge)



Note: Never mix bleach with acidic substances (e.g. vinegar or soft drink) or alcohol to avoid the production of harmful gases.


 





Learning from the Nature – Artificial Lotus Effect
Published on 27 January 2021

Previously we have shared with you a master of superhydrophobicity in nature – lotus leaf. In fact, we have applied the lotus effect in our daily lives as well. In recent years, superhydrophobic spray has been on market to endow the surfaces of clothes, shoes and building materials with extreme water repellency and dirt-proof ability like the lotus leaves. By applying the spray on a marble maze, water droplets can be used in place of the marbles!

Superhydrophobicity can also be applied in product containers. Have you noticed that when a viscous liquid product such as honey or tomato sauce is almost used up, the last bit always remains inside the bottle and is annoyingly hard to get out? It is a plain waste of food. If food grade superhydrophobic coatings are applied on the interior of packaging containers, even the last few drops of products, no matter how viscous, can be poured out and no food is wasted.

If you want to create the lotus effect for yourself, read on for the simple experiment. Dissolve some clear silicone sealant in paint thinner. Then, soak the cotton fabric in the solution for a while. After the fabric dried, water droplets can roll on the surface (Note: Kids should ask an adult for help. Be sure to conduct the experiment in a well-ventilated place, and do not inhale the volatiles from the paint thinner or be close to the fire).

DIY Lotus Effect

1) Prepare materials, equipment and the cotton fabric.

1) Prepare materials, equipment and the cotton fabric.

2) Add the clear silicone sealant to the paint thinner.

2) Add the clear silicone sealant to the paint thinner.

3) Shake the bottle to mix them together until the solution turns milky.

3) Shake the bottle to mix them together until the solution turns milky.

4) Soak the cotton fabric in the solution for about 10 minutes. Then, take it out and leave it to dry.

4) Soak the cotton fabric in the solution for about 10 minutes. Then, take it out and leave it to dry.

5) The fabric turns into a superhydrophobic surface!

5) The fabric turns into a superhydrophobic surface!


 


 





Superhydrophobicity Keeps Lotus Leaves Clean
Published on 31 December 2020


Video demonstrates the superhydrophobicity of lotus leaves

The video above demonstrates the marvellous water repellency of lotus leaves. However, if you have ever touched a lotus leaf, you may recall that its texture is not particularly smooth. So why the lotus leaves repel water much better than the leaves of other plants?

There are pictures captured by optical microscope in the video which show the numerous fingertip-like bumps (papillae) on a lotus leaf surface. A tiny bump measures only about 10 microns across and is much thinner than a hair. When observed with an electron microscope, the bumps can be seen covered by countless nanoscale wax tubules (with a diameter around 100 nanometres). Wax is hydrophobic, or in simpler terms, it dislikes water.


Image of lotus leaf surface captured by scanning electron microscope (Photo credit: Superhydrophobicity in Perfection: the Outstanding Properties of the Lotus Leaf Ensikat, H. J.; Ditsche-Kuru, P.; Neinhuis, C.; Barthlott, W. Beilstein J. Nanotechnol. 2011, 2, 152–161. https://doi.org/10.3762/bjnano.2.19 )

 

When water contacts with the lotus leaf, the bumps covered by hydrophobic wax tubules and the water's own surface tension prevent the water from seeping into the spaces between the bumps, and facilitate the water to hold itself as a spherical droplet. The actual contact area between the droplet and the leaf surface is tiny. With less force of adhesion, the droplet can roll off easily. The video also shows that water does not turn into spherical droplets on a piece of paper. The water tends to stay and wet the paper, instead of rolling off.


Compare the shape of water droplets on lotus leaf and paper
Compare the shape of water droplets on lotus leaf and paper

Growing in rivers and ponds with slow water flow, the lotus has evolved leaves with excellent water repellency to minimize water accumulating on the leaves. The rolling water droplets can also sweep the mud and dust away from the surface, preventing the blockage of sunlight or leaf rotting from happening. Beside lotus leaves, butterfly wings also have excellent water repellency thanks to their rough surface structures. Butterfly wings are covered by numerous scales. The arrangement of scales and the tiny nanostructure on them ensure that water rolls off the wings swiftly and does not hinder the butterfly's flight, especially in rain.


Slow motion video shows water rolling off the butterfly wings

Organisms have evolved different body structures and abilities to adapt to the environment. They provide us with inspiration for developing new products. The lotus effect has been applied to daily water-repelling products. Have you ever used these products?


 

 


The Science Behind Aiyu Jelly
Published on 20 November 2020

Most of us who are fond of desserts and Taiwanese beverages have tried the chewy Aiyu jelly, one of the most popular toppings, but do you know how it is made?

Aiyu jelly is made from a plant called Jelly Fig. By rubbing a pouch of Jelly Fig seeds in boiled water at room temperature and letting the water extract sit for a while, the water will turn into a gelatinous substance like a magic trick. Why Aiyu jelly can be made by just rubbing the seeds in room temperature water without heating or cooling in the fridge?

The outer layer of Jelly Fig seeds is rich in pectin and pectinesterase (an enzyme), they gradually dissolve into the water during the rubbing process. Pectin is a long-chained polysaccharide. The pectinesterase modifies certain structures in the long-chained pectin, allowing pectin to combine with the metal ions in water (tap water in Hong Kong contains trace metal ions such as calcium ions and magnesium ions). This cross-linking reaction among pectin chains and metal ions forms a sponge-like network which traps water and results in a gelatinous substance.

 


Above diagram illustrates the cross-linking reaction <br>between the pectin and metal ions in the water
Above diagram illustrates the cross-linking reaction
between the pectin and metal ions in the water
The fruit of Creeping Fig and the seeds inside it
The fruit of Creeping Fig and the seeds inside it


Jelly Fig has a close relative in Hong Kong – the Creeping Fig. Both belong to ficus plants, and have similar fruit structure (both are syconium). As some books mentioned, a kind of dessert known as white jelly which was sold on the streets of Hong Kong before 1950s, was made from the Creeping Fig. The production process is similar to that of Aiyu jelly.

Pectin can be found in apples, grapes and many other fruits. It has a lot of applications in our daily lives, especially in the food manufacturing industry, such as making jam and yoghurt. Pectin is even used in producing cosmetic and personal care products, including lotion and shampoo. Fruits are really great for you!

 

Steps of making Aiyu Jelly

1) Get some Jelly Fig seeds and boiled water or mineral water at room temperature, the ratio is about 1 gram of seeds to about 50 ml of water. Note: Distilled water is not suitable, as it lacks metal ions. No grease on both hands and the apparatus. Grease will hinder the linking of pectin and metal ions.

1) Get some Jelly Fig seeds and boiled water or mineral water at room temperature, the ratio is about 1 gram of seeds to about 50 ml of water.

    Note:
  • Distilled water is not suitable, as it lacks metal ions.
  • No grease on both hands and the apparatus. Grease will hinder the linking of pectin and metal ions.
2) Put the Jelly Fig seeds into a cloth pouch, then rub it gently in water for 10-15 mins. The pectin and pectinesterase will dissolve into the water gradually. Note: Do not rub longer than 15 mins and rub gently, otherwise Aiyu jelly may not set.

2) Put the Jelly Fig seeds into a cloth pouch, then rub it gently in water for 10-15 mins. The pectin and pectinesterase will dissolve into the water gradually.

    Note:
  • Do not rub longer than 15 mins and rub gently, otherwise Aiyu jelly may not set.
3) After rubbing, the water extract is pale yellow with increased thickness. Let it sit for 30-40 mins at room temperature, then the Aiyu jelly is set and ready to serve. Note: The sitting is to allow sufficient time for the pectin and metal ions to link, so do not stir the water extract after rubbing.

3) After rubbing, the water extract is pale yellow with increased thickness. Let it sit for 30-40 mins at room temperature, then the Aiyu jelly is set and ready to serve.

    Note:
  • The sitting is to allow sufficient time for the pectin and metal ions to link, so do not stir the water extract after rubbing.
4) Aiyu jelly can be stored in the refrigerator. Before consuming, flavours or toppings are usually added to the bland Aiyu jelly.

4) Aiyu jelly can be stored in the refrigerator. Before consuming, flavours or toppings are usually added to the bland Aiyu jelly.


 


 





Plastic Bags, Soluble in Water?

Published on 2 November 2020

It is shocking that over 4 billion plastic bags are disposed every year in Hong Kong. Plastic bags are notoriously difficult to decompose naturally, and causing many environmental problems. However, it is hard to give up using plastic bags in our daily lives, therefore reducing the use of plastic bags or reusing them is the utmost thing to do, followed by choosing alternative products with less environmental impact. Recently, plastic bags made of polyvinyl alcohol and starch can be found on the market.

Since polyvinyl alcohol is a water-soluble polymer, these plastic bags can be dissolved in hot water and degraded to carbon dioxide and water by microorganisms. There are many products made of polyvinyl alcohol, such as the outer film of the widely available laundry detergent pods. The film dissolves in water and disappears during the laundry process.


In the video, you may observe the difference between conventional plastic bags and polyvinyl alcohol plastic bags in hot water.

Moreover, the clear liquid glue used for crafting is a water solution of polyvinyl alcohol. You can try pouring some liquid glue on a flat surface and let it dry, and see if the texture of the dried film is similar to that of a plastic bag.


Clear liquid glue made of polyvinyl alcohol and its dried film.
Clear liquid glue made of polyvinyl alcohol and its dried film.

Even though polyvinyl alcohol plastic bags might not be the perfect substitute to conventional plastic bags, it is always good to be more informed about these substitutes that we can make a greener choice in our daily lives. But no matter which plastic bag you choose, consider to reduce and reuse them for saving the environment.


 

 


Animals with a Loud Voice (2): Cicada

Published on 7 October 2020 

When talking about animals with a loud voice, how could we miss cicadas? Every summer we can hear cicadas chirping in urban parks and countryside. Some species of cicadas can produce sound reaching 100 decibels (dB), as loud as an operating electric drill. How does a little cicada make such a loud sound? Firstly, only male cicadas can chirp, so as to attract females by the resounding calls. A male cicada has three specialised components in his abdomens: muscles, tymbals and a hollow abdominal cavity. In contrast, the abdominal structure of a female cicada is much simpler. You can see the differences in the pictures below.


Transverse section of first abdominal segment of cicada specimen
Transverse section of first abdominal segment of cicada specimen
Location of tymbal on one side of a male cicada
Location of tymbal on one side of a male cicada

Inside the abdomen of a male cicada, there is a pair of V-shaped muscles attaching to the tymbals on each side of the body. The tymbals resemble a piece of plastic sheet. When they are pulled by the muscles and deform, they produce sound. In the video below, you can see the demonstration on how the tymbal makes sound using a plastic water bottle. The clicking action of cicadas' tymbals is, of course, much faster - it can reach around 400 times per second. Moreover, the structure of the abdomen of a cicada is quite different from other insects, it has a hollow abdominal cavity. The sound produced by the tymbals resonates in the cavity and gets amplified. It works like the soundbox of a wooden guitar.

Scientists are eager to find out how do the cicadas produce a loud sound with less energy, and apply the working principles to our daily lives, such as improving the sonar detection technology. You can study the sound-producing principles of cicadas too, such as using the plastic water bottle to imitate cicadas' chirp as shown in the video or try to build your own soundbox to amplify sound.


Video demonstrates how sound is produced by the muscles in male cicada's abdomen pulling the tymbals


 

 


Animals with a Loud Voice (1): Gunther's Frog

Published on 6 October 2020 

We humans communicate through spoken words, while animals communicate with other members of the species by making different calls. Some animals can make a very loud call even they are small in size. Have you ever encountered these animals with a loud voice?

When you go near streams or ponds in the parks during spring and summer, you may encounter one of the animals with a loud voice - Gunther's Frog. Gunther's Frogs are common in Hong Kong. Being amphibians, they can be found in streams, ponds and wet agricultural land.


Video: Gunther's Frog is croaking

Why do Gunther's Frogs croak so loudly? Because spring and summer are their breeding seasons and the males have to sing aloud to attract the females. They need to warn off occasional intruding males, too. To perform the attractive masculine calls, male Gunther's Frogs have evolved a specialised body part. In the video, you can see when the male frog croaks, he closes his mouth and inflates the two balloon-like "vocal sacs" under the mouth.

How does a Gunther Frog make a sound?
1. Mouth closed and air expelled from the lungs
2. The expelled air passes through the larynx and vibrates the vocal cords, thus the sound is produced
3. The air finally blows up the vocal sacs, and the sound produced by a vocal cord is emitted out from the vocal sacs

The vocal sacs are as elastic as a balloon, so they recoil and deflate after a croak. The air quickly refills the lungs and with this breathing technique, Gunther's Frogs can croak for a long time. In addition to facilitating the croaking, the inflated vocal sacs also enhance the male's visual attractiveness to the females.

In nature, as each species of frog has a distinct croak, scientists have recorded their croaks to plot the acoustic spectrograms to analyze how the frequencies change with time. These data are useful in ecological surveys and related scientific research. Next time you hear the croaking frogs, other than listening appreciatively, you may record the croaks with your smartphone. Try analyzing the croaks with free apps and comparing with other sounds. Discoveries are waiting for you!


Acoustic spectrogram of Gunther's Frogs' croaks
Acoustic spectrogram of Gunther's Frogs' croaks
The vocal sacs under the mouth of a male Gunther's Frog inflate when croaking
The vocal sacs under the mouth of a male Gunther's Frog inflate when croaking


 

 


The Spectrum of Lightning

Published on 30 September 2020 

Thunderstorms are common in the summer in Hong Kong and one can occasionally sends out several thousand lightning strokes. But what is the secret behind the dazzling flash which can lit up the whole sky?

For something that gives off light, studying its spectrum is a good way to understand it. You can obtain the spectrum of lightning by covering the lens of a smartphone with a small piece of diffraction grating when filming the natural phenomenon. In the spectrum, several lines of colour stand out. They are the emission lines of nitrogen ions. We just witnessed nitrogen in the air being ionized by the intense heat of lightning.

Although lightning is an atmospheric phenomenon, it is vital to organisms as well. After being ionized, the nitrogen in the air will combine with oxygen to form nitrogen oxides. The rain will bring them into the soil and becomes nitrates, constituents of fertilizer. Hence, nitrogen in the air enters the food chain and help to build up the proteins in organisms. (Note: atmospheric nitrogen can also be transformed into ammonia by microbial activity, and then utilized by other organisms.)

Spectrum of lightning can be photographed indoor. For safety, never go to an open field during a thunderstorm.






 

 


The Secret of Delicate Foam

Published on 18 August 2020 

Keeping our hands clean is one of the best ways to avoid getting sick. In recent years, many liquid soap companies have launched the foam version of their products. On one pump, the liquid soap from the bottle turns into the foam in your hands. But why it does not have to be contained in a metal spray bottle with pressurised gas? Is the hand soap specially formulated? Or are there other reasons?

I was eager to find out the answer so I took a foam pump apart. (Figure 1) Besides the tubes and springs which can be seen in an ordinary liquid soap pump, I found a small cylinder which had fine mesh at both ends. If the cylinder was taken away, what came out from the nozzle would only be jets of liquid soap instead of foam. This proved that the tiny cylinder was crucial in the foam making process. (Figure 2 and Figure 3)

After that, I successfully made foam by substituting the mesh with cotton pads, scrub sponge, and even the middle layer of a surgical mask. From our observation, the finer the pores are, the smoother the foam will be. Recently, a foaming body wash which advertises itself as cream-like has hit the shelves. The bottle is unique with the addition of an extra mesh layer at the tip of the nozzle. (Figure 4)

Although the foam pump can produce foam from liquid soap, for consistent foam the water-to-soap ratio of the liquid has to be optimised. If it is too thin, the foam produced cannot hold its form. If it is too thick, the liquid soap may block the mesh and produce no foam. The takeaway of this exploratory teardown is that a trivial thing such as hand washing can become more convenient and interesting with the ingenuity of the inventors.


Figure 1. Structure of a foam pump<br><br><br>
Figure 1. Structure of a foam pump


Figure 2. The upper mesh is finer than the bottom one<br><br>
Figure 2. The upper mesh is finer than the bottom one


Figure 3. Mechanism of foam making<br><br>
Figure 3. Mechanism of foam making

<br><br>


<br><br>


Figure 4. An extra, fine layer of mesh can form cream-like foam.
Figure 4. An extra, fine layer of mesh can form cream-like foam.
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Please click here for video.
The Science Behind Dalgona Coffee
 
Published on 5 June 2020
 
Coffee is one of the most common beverages. Then what is so special about the trendy Dalgona Coffee? Does the secret of the smooth and frothy foam lie in the caffeine of coffee? Let's find out in the video with Paulina, Museum Director of the Hong Kong Science Museum and Dr. Emily, Assistant Professor of Science Education, Department of Chemistry, The Hong Kong University of Science and Technology!

 


 



 
   
   


Sea of Spider Tree Flowers in the Urban Areas

Published on 9 April 2020

In springs, my friends always travelled abroad to enjoy beautiful scenery of flowers. But by picking the right time, you can still find beautiful trees and flowers in the urban areas of Hong Kong.

Spider Tree is one of the must-sees. It is a common deciduous urban tree in Hong Kong and may reach 15 metres in height. It has a Chinese name which means "vegetables on the treetop". What is it meant? People in Yunnan province of China pickle the young leaves of Spider Tree as a preserved vegetable. Besides, the wood of Spider Tree is light yet strong, and can be crafted into fish-shaped wooden baits.

Spider Tree has elegant tree form and it flowers from mid to late-April. There are luxuriant flowers clustered at the ends of the branches during blossoming. After the spring rains, I love walking along Prince Edward Road West, Boundary Street or Chatham Road South near the Science Museum to immerse myself in the magnificent sea of creamy yellow flowers of the Spider Trees there. These flowers are quite special if you take a closer look at them. The white coloured petals will turn yellow gradually. Each flower possesses many elongated stamens which are much longer than the petals. The elongated stamens look like the spider legs and this is why the tree gets its name as "Spider Tree".

Planting trees in the urban areas not only beautifies our environment, but is also beneficial to the ecology. The larvae of Great Orange Tip butterflies feed on the leaves of Spider Tree, and that means you have a good chance to see the largest Pieridae butterflies in Hong Kong flying around.

 

The sea of Spider Tree flowers.<br><br><br>
The sea of Spider Tree flowers.


The colour of Spider Tree flowers will change from white to yellow gradually.<br><br>
The colour of Spider Tree flowers will change from white to yellow gradually.

Each flower of Spider Tree possesses ten or more dark red stamens.
Each flower of Spider Tree possesses ten or more dark red stamens.
Great Orange Tip, as its name suggests, has large attractive orange patches on its wing tips.
Great Orange Tip, as its name suggests, has large attractive orange patches on its wing tips.


 

 


Get to Know the Trees in Hong Kong by Starting with Tree Cotton

Published on 23 Mar 2020

Every year from March to April, the big red flowers of Tree Cotton always catch my eyes when I am strolling along the streets in Hong Kong. Tree Cotton, also known as Red Kapok Tree or Hero Tree, is a flowering deciduous tree with tall and straight trunk that may reach 25 metres in height. Tree Cotton is widely cultivated in Hong Kong and you can find the trees along the road or in the parks in many districts.

Tree Cotton's value is more than meets our eyes. The dried flowers can be used as a Chinese Medicine and is one of the ingredients of the Chinese Herbal Tea. Its tree bark and root are also used as Chinese Medicines for getting rid of heatiness and detoxification. In addition, Tree Cotton contributes much to the local ecology. The nectar produced by its flowers is a delicacy to some commonly seen birds, such as Red-whiskered Bulbul, Crested Myna and Swinhoe's White-eye. They can be found feasting on the blossoming tree. Don't miss the chance to enjoy bird-watching while appreciating the flowers.

When the birds and insects feed on the nectar of the flowers, they unwittingly help the Tree Cotton to pollinate. The pollinated flowers will then grow into 10 to 15-centimetre long fruits. When mature, the fruit capsules burst open and the wind will carry numerous seeds wrapped in fluffy cotton into the air in their search for a new home. In May, we can enjoy the beautiful scene of fluffy flakes drifting down from the trees.

We may not pay much attention to Tree Cotton in the hustle and bustle of our lives. However, Tree Cotton is not completely unknown to us because its heroic image has been mentioned in textbooks and Cantopop songs. Starting from today, let's slow down the pace to appreciate the trees, and admire the beauty of nature!


Flowering Tree Cotton<br><br><br><br>
Flowering Tree Cotton



The seeds wrapped in fluffy cotton are very light in weight, and can be dispersed far by wind.<br><br><br>
The seeds wrapped in fluffy cotton are very light in weight, and can be dispersed far by wind.


Nectar in the flowers of Tree Cotton is a delicacy to the birds.
Nectar in the flowers of Tree Cotton is a delicacy to the birds.
 


 

Last Modified: 21-05-2021

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