The Hong Kong Science Museum has recently established the Science Promotion Unit. Featuring curiosity, creativity, playfulness and collaboration, we organise online and offline programmes to share interesting science-related topics, and encourage everyone to explore the incredible world of science in our daily lives. QK POST is our first programme. "QK" stands for "Quest for Knowledge". We hope to share various scientific knowledge through online platforms. Stay tuned for our latest news!
The Hong Kong Jockey Club Series: Science in Art
As part of the "Art@Harbour" exhibition, the Science Promotion Unit and the Art Promotion Office join hands to organise the exhibition "The Hong Kong Jockey Club Series: Science in Art" which is exclusively sponsored by The Hong Kong Jockey Club with the theme of science and art. We have invited a guest curator and commissioned groups of local artists as well as a cross-disciplinary artist to create multiple large-scale outdoor art installations, infusing with art, science, technology, engineering and mathematics. With special lighting effects, the installations illuminate Victoria Harbour in a play of light and shadow.
The Science Promotion Unit has commissioned Mr Victor Wong, a cross disciplinary artist, to create a series of large-scale art installations named as Decoding Nature, which is inspired by the mathematical structures in nature and sea creatures. Visitors could discover the mysteries of science while appreciating the beauty of art and nature through the art pieces. The series includes a turtle-shaped parametric structure titled Loving Home, a group of metallic sculptures titled Coral Fractals and a piece of stone-mural titled Eternal Light of a Seashell.
During the exhibition period, we will organise a series of extension activities, such as online guided tours, artist and scientist sharing sessions, to let the public explore the realms of art and science.
For exhibition and programme details, please visit https://scienceinart.hk/
Cross disciplinary artist, Mr Victor Wong, introduces the design concept of Decoding Nature.
QKPOST: Science Vocabulary A to Z - T for Time
We can walk to the left, to the right, forward or backward, but on the timeline, we can only move forward, and time travel may only happen in sci-fi movies.
So, how to measure time? From sunrise on a day to the next is 24 hours, is it really that simple? In ancient China, a day was divided into 12 double hours, and each double hour was equal to 2 hours. But to measure the time precisely, we need an atomic clock.
The design of an atomic clock is simply to define time based on frequency. When electrons travel through different orbitals surrounding the atomic nucleus, they absorb and release electromagnetic waves with specific frequency, which is called atomic resonance frequency. The resonance frequency is very stable, much like a metronome. Take caesium-133 atom as an example, its resonance frequency is 9,192,631,770 cycles per second. By measuring the resonance frequency of caesium atom in an atomic clock, we can determine the length of a second precisely. The caesium atomic clock is highly accurate with an uncertainty of only one second every 300 million years. The Hong Kong Observatory also provides time service based on a caesium beam atomic clock.
Does each person feel the passage of time in the same way?
"The Hong Kong Jockey Club Series: Science in Art" Artist Sharing Session
With the theme of "Decoding Nature","The Hong Kong Jockey Club Series: Science in Art" Artist Sharing Session invited the cross disciplinary artist, Victor Wong, to share the design concept of creating the "Decoding Nature" series, the interesting stories and difficulties encountered from the design stage till completion. He also discussed the interesting connections between art, science and technology.
Moderator: Paulina Chan (Museum Director of Hong Kong Science Museum)
Speaker: Victor Wong (Cross Disciplinary Artist)
*All the content of works are independently produced by the organiser/creative team, and do not reflect the views or opinions of The Hong Kong Jockey Club Series nor the Sponsor.
QK Lifestyle: What is the secret behind whipping egg whites?
Which dessert is your favourite? Cloud egg toast, meringue cookies or macarons?
No matter which of the dessert you like most, the common step of making these dessert is to whip the egg whites. What is the secret behind this important step?
An egg white is composed of about 90% water and 10% protein, in which the protein molecules are long chains of amino acids folded into spherical tangles. Whipping will introduce air bubbles into the egg whites and unfold the protein molecules. The water and protein molecules rearrange and trap the air.
Continuous whipping causes the protein molecules to form a network, making the egg white foam firmer. At this moment, you should be able to put the whole bowl of egg white foam upside down above your head without any egg whites falling on your head! But in case you don't whip enough, you will have to wash your hair!
Do you know why we should not mix in the egg yolks when whipping egg whites?
QKPOST: Science Vocabulary A to Z - S for Stars
Twinkle, twinkle, little stars… we all know how to sing the song, but do you know that the Sun is a star too? Why do stars shine and twinkle?
Most of the celestial bodies we see in the night sky are stars, which emit light themselves, just like the Sun. Although they look so tiny, they are actually huge balls of gas mainly composed of hydrogen and helium, which produce a lot of light and heat by nuclear reactions, so we can see them glowing even they are so far away!
We often see stars twinkle. In fact, they don't. It is just an optical illusion! When starlight passes through the atmosphere, it will be refracted and its direction will be changed before reaching our eyes by air of different temperatures and air currents. When the starlight is bent away from our eyes, the star seems to disappear temporarily. But when it hits our eyes, the star reappears. The starlight jumps in and out of sight, you can see it for a while and then you can't see it in the next moment, creating the twinkling effect.
Do you know what kind of "stars" do not twinkle?
QKPOST: Guess what it is in the magnified photo
Are they meteor hammers? Or the burdock seeds which attach to our clothes? Not at all! Can you guess what they are? These are the pollen grains of sunflowers!
Pollen grains play an important role in the reproduction of seed plants. They are formed in the male structures of seed plants and transported to the female structures by wind, water or insects for fertilisation.
The minute pollen grains not only make plants bloom but they are also very useful. The outermost layer of pollen grains is composed of a substance called sporopollenin, which is resistant to high temperature, strong acids or bases. It can withstand the adverse environment and can even be preserved in sediment for millions of years! Moreover, pollen grains of different species show variation in shape, size, surface pattern and number of apertures. Coupled with its widespread dispersion, pollen analysis has been applied in various fields. For example, forensic scientists analyse pollens for crime investigation. Paleobotanists can reconstruct the environment of thousands or even millions of years ago by studying pollen grains. Oil companies study pollen fossils to search for oil.
Do you know any other uses of pollen grains?
QKPOST: Science Vocabulary A to Z - R for Radiation
"Radiation" often makes people fearful and even reminds them of nuclear accidents. In fact, radiation is everywhere and is part of daily lives.
Radiation is a form of energy transmitted by matter, either as electromagnetic waves or particles. Radiation can be classified into natural and artificial radiation.
All living things on Earth are exposed to low-energy natural radiation, including cosmic rays, radioactive materials in rocks, soil, food, and radon in the air. The human body also contains radioactive particles, such as potassium-40, uranium, carbon-14, etc. Due to the low level of radiation, it will not affect the human body.
Artificial radiation includes X-ray and cancer radiotherapy, etc. The dosage of a chest X-ray is equivalent to 10 days of natural background radiation. However, for diagnosing diseases, it has more benefits than risks.
Will we receive more radiation when we ride a plane?
QK Lifestyle: How many cuttlefish are there in the picture?
It's the season to catch some cuttlefish! When you catch cuttlefish, can you tell if the "cuttlefish" you've caught is a cuttlefish? Let's play a game now. Do you know how many cuttlefish are in the picture?
The answer is four! In the picture, there are cuttlefish, squid and octopus. Although they are all called "fish" in Chinese, they are molluscs, not fish. You can recognise octopus easily as it has eight arms; squid and cuttlefish have eight arms and two tentacles, which can be easily mixed up. How to tell a squid from a cuttlefish? A squid has a relatively narrow body with triangular fins; while a cuttlefish is oval and has an inner shell commonly known as "cuttlefish bone". When you take a closer look, you will find that most of the "cuttlefish" you caught are actually squid!
Cuttlefish, squid and octopus are delicacies of many creatures, so they must protect themselves and have to be the "masters of disguise" in nature. Their skin has many chromatophores, surrounded by muscle fibres responsible for controlling the area of pigment. When receiving a nerve signal, the muscle fibres contract or relax, causing the pigment cells to expand or contract to change their body colour. So they can disguise themselves as the surrounding environment to avoid turning into other's meal!
Apart from them, do you know any other "masters of disguise" in nature?
QKPOST: Science Vocabulary A to Z - Q for Quartz
What do you think of when you talk about quartz? I will think of a beautiful quartz watch! Is there really quartz in a quartz watch? What is quartz?
Quartz is a common mineral in the Earth's crust and formed by the crystallisation of magma or hydrothermal fluid at a relatively low temperature. Its main component is silicon dioxide (SiO2). In fact, the transparent rock crystal is one of the varieties of quartz. Some coloured crystals, such as amethyst, rose quartz and citrine, are actually quartz crystals with impurities.
Quartz crystal is a piezoelectric material that generates a voltage when it is subjected to pressure. Conversely, applying a voltage to its surface will slightly change its shape. When connected with batteries, the quartz crystal in a quartz watch will vibrate at a regular frequency, driving other components to rotate the hands. Because the vibration frequency is very stable, quartz watches are very accurate.
Do you know any other uses of quartz in our daily lives?
QKPOST: Science Vocabulary A to Z - P for Plasma
What is the fourth state of matter?
All of us are familiar with the three states of matter. Taking water as an example, when water (liquid state) is cooled to zero degree, it becomes ice (solid state); and when it is heated, it becomes steam (gas state). If the steam is continuously heated, the water molecules will separate into positively charged ions and negatively charged electrons. They are roughly equal in number and can move freely. This cloud of charged particles is named as plasma. It is the fourth state of matter, in addition to solid, liquid, and gas states. We can also use electricity, electromagnetic waves, etc. to provide sufficient energy to change a gas to plasma.
Plasma may seem so remote, but in fact, 99% of the matter in the universe exists in plasma state. The sun is a huge ball of plasma. Natural phenomena such as lightning and auroras have plasma. Fluorescent lamp and plasma TV also make use of plasma.
Do you know any other application of plasma in everyday life?
QK Lifestyle: Which one is your favourite tea?
Which one is your favourite, green tea, oolong tea or black tea? The taste, aroma and appearance of these three kinds of tea are different. What are the factors that make them different? It is the degree of fermentation!
Tea fermentation is different from other foods. Food fermentation generally depends on the action of microorganisms, while tea fermentation refers to the oxidation between enzymes and tea polyphenols in freshly picked tea leaves. Tea polyphenols will be converted into other chemicals in this process.
Since tea polyphenols are the main source of taste and aroma, tea makers will use heat to stop the action of the enzymes to control the degree of oxidation and produce different types of tea.
Green tea is unfermented, meaning that the leaves are heated immediately after picking, and the enzymes cannot work, so it retains the most original taste and has a greener colour. Oolong tea is semi-fermented, where the leaves are heated after a period of time after picking. Black tea is fully fermented, where its colour mainly comes from theaflavins or thearubigins produced after fermentation.
Do you know the difference between pu-erh tea and the above three kinds of tea?
QK Guess: Guess what they are?
Are they pieces of wood? Or crystals? Here is a tip: they frequently appear around us, yet we usually are not aware of them! Do you know what they are?
They are crystals of monosodium glutamate (MSG)! MSG, also known as sodium glutamate, is a food flavouring in form of white crystals. When it dissolves in water, it releases glutamates (one of the components of protein) to stimulate our taste buds and produces the sense of "umami".
Umami, sweet, sour, bitter and salty are the five basic tastes of human beings. Umami can usually be tasted in protein-rich food such as fish and meat, and is a signal of protein intake for our body. When we taste umami, it will trigger the secretion of saliva and digestive juice for protein digestion.
Glutamate-rich food, such as parmesan cheese, ripe tomatoes and dried mushrooms are good to enhance umami in dishes.
Do you know which kinds of food have natural taste of umami?
QKPOST: Science Vocabulary A to Z - O for Ozone
Nature is really amazing. Even if different matters are made up of the same atom, their chemical and physical properties will vary depending on the number of atoms that make them up. Ozone (O3) is made up of three oxygen atoms and has different properties than oxygen (O2). It has strong oxidizing power and is highly irritating.
When we talk about ozone, we will always think of the ozone layer that shields us from ultraviolet radiation. So, is ozone always beneficial?
Our love and hate for ozone depend on its location and concentration above the ground. We love it when it exists at a high concentration 10-50 kilometers above the ground (stratosphere). This area is the ozone layer. It acts like a shield that absorbs most of the ultraviolet radiation from the Sun, protecting lives on the Earth.
We hate ozone when its concentration rises in our surroundings. Since it has strong oxidizing power and is highly irritating, it will irritate our respiratory system and cause damage when we are exposed to high concentration of ozone.
Do you know how ozone is produced on the ground?
QK Lifestyle: What is the hidden secret of hydrangea's colour?
From April to May every year, colourful hydrangeas can be found in many parks in Hong Kong, such as Hong Kong Park, Hong Kong Zoological and Botanical Gardens and Tai Po Waterfront Park. Besides light blue and red ones, hydrangeas also have lavender purple and pink colour! What is the hidden secret of hydrangea's colour?
It is...chemical reaction causing the change in flower colour! The colour of hydrangea does not come from its petals but the calyx, which contains delphinidin, a kind of anthocyanins. Its colour varies depending on the soil pH and the concentration of aluminium ions (Al3+).
In acidic soil environment, aluminium ions can be absorbed by the hydrangea and react with delphinidin, turning them blue. The concentration of aluminium ions affects the production of blue delphinidin in hydrangea, making the calyx with different shades of blue or purple!
In alkaline soil environment, aluminium ions (Al3+) will combine with hydroxide ions (OH-) to form aluminium hydroxide (Al(OH)3), which cannot be absorbed by the hydrangea. The mentioned chemical reaction cannot undergo and delphinidin in the calyx will become red colour!
QKPOST: Guess what it is in the magnified photo
Is it the latest nail art, or a colourful gift wrap? Nature is full of colour, waiting for us to explore! Do you know what the picture shows? The answer is butterfly wing!
Butterfly wings have many very tiny scales. The rich colours of butterflies mainly come from the intrinsic colours of the scales and the unique "structural colour".
"Structural colour" refers to the colour appearing after reflection, interference, diffraction and other optical phenomena due to the special arrangement of the scales when they are exposed to sunlight. The colour lustre will also vary depending on our viewing angle, making the butterfly wings look dazzling!
In addition to butterflies, do you know which animals have "structural colour"?
QKPOST: Science Vocabulary A to Z - N for Neutron
Atoms are the basic building blocks of all matter. Then, what's inside an atom?
At the center of an atom is the nucleus, consisting of positively-charged protons and neutral neutrons. Negatively-charged electrons orbit around the nucleus. For example, the nucleus of carbon-12 atom has six neutrons and six protons, and has six electrons orbiting around.
An element may have "sibling" atoms, with the same number of protons but different numbers of neutrons, which are called "isotopes". Their chemical properties are similar, but their stability is different. For example, the isotope carbon-14 has two more neutrons and is less stable than carbon-12. It decays into nitrogen-14 and releases energy in the process. About every 5,700 years, the number of carbon-14 atoms in an object is halved. With this rule, archaeologists can estimate the age of ancient creatures by detecting the amount of carbon-14 content in a fossil.
Do you know how far back in time can carbon-14 date? How scientists make use of nuclear decay to change human life?
QKPOST: Science Vocabulary A to Z - M for Mass
In everyday life, to describe how heavy an object is, we would use weight in kilograms (kg) to represent it. However, physicists use more specific terms to tell how heavy an object is, i.e. mass and weight. Mass is the amount of matter an object contains, expressed in kilograms (kg), while weight is the force exerted on an object by the gravity of the Earth, expressed in Newtons (N). Are they both the same?
To explain it more clearly, the only way is to send you to the Moon! The amount of matter in your body does not change no matter where you are. But since the gravity of the Moon is one-sixth of that of the Earth, your weight is also one-sixth of that on the Earth. If you weigh 60kg on Earth, you will only weigh 10kg on the Moon. The conclusion is that the fastest way to lose your "weight" is to travel to a planet with less gravity but if you want to lose "mass", doing more exercise is the key!
Do you know on which planet in the solar system will you weigh the least?
QKPOST: How do sunflowers master mathematics?
The splendid sunflowers are full of vigour, bringing passion and warmth. Many people think of sunflower as just a single large flower, but it is actually an inflorescence composed of many small flowers, which produce the familiar sunflower seeds when they wither.
Nature is definitely a brilliant mathematician. In order to produce more seeds, sunflower regulates to arrange the small flowers at a mathematical golden angle of 137.5 degrees. If you observe the sunflower in detail, you will find the angle between the first and the second small flower is 137.5 degrees, the second and the third small flower are also 137.5 degrees apart, and so on. With the repetition of this pattern, the sunflower seeds will be arranged tightly in a spiral shape without overlapping.
Do you know how is 137.5 degrees derived from? Are there other examples of the golden angle in nature?
QKPOST: Science Vocabulary A to Z - L for Light
Visible light, or simply light, that we can see is actually electromagnetic wave that occupies only a small part of the whole spectrum with wavelengths ranging from 400nm to 700nm. In addition to visible light, ultraviolet and infrared are also electromagnetic waves.
In addition to bringing the blue sky and rainbows to us, light is also widely used in today's communication technology to revolutionize our life. How do scientists use light to transmit signals through optical fibres so that we can play online games and stream movies all the time? It simply relies on a physics phenomenon – total internal reflection.
Do you know what are optical fibres made of? Why are they as thin as a hair?
QKPOST: Science Vocabulary A to Z - K for Kelvin
The Kelvin introduced today is not my friend Kelvin, but the international unit of thermodynamic temperature scale, which is known as the Kelvin temperature scale, with K as the unit, invented by Lord Kelvin from Ireland.
The temperature of an object is the measurement of kinetic energy of particles in the object. For example, in a glass of boiling water, water particles move vigorously. On the other hand, as water cools, the water particles move slower, and the kinetic energy will be reduced. According to thermodynamics, the zero kelvin or absolute zero refers to the lowest possible temperature, representing the minimum energy of particles, which is equivalent to -273.15°C.
Looks confusing? Don't worry, the increment magnitude in the Kelvin temperature scale is the same as the Celsius scale, but with different values. The freezing point of water is 0°C (Celsius) = 273.15K (Kelvin).
Will the properties of matter be changed under such extremely low temperature? Also, do you know where the coldest place in the universe is?
Science Online Tour @ The "Science Machina" Exhibition (13.11.2021)
Science and machines contribute to many major inventions and achievements, and explore many possibilities for the future. The "Science Machina" exhibition depicted state-of-the-art scientific machines through imagery and comics in an unconventional way, thus bringing together the world of art and science.
In this online guided tour, the curator and assistant curators of Science Promotion Unit introduced these scientific machines as well as the virtual reality experience of "I Will Sleep When I'm Dead" to dive into the neurons, synapses and thoughts in our brain.
Science Cafe Sharing Session by Science Gurus (11, 18, 25.9.2021)
A cup of fragrant coffee is relaxing. Yet, its flavour is no different from science, both inviting for continuous exploration. Science Promotion Unit has cooperated with the "Listening" team to organise a pop up "Science Cafe". Experts from three scientific fields shared their stories in the aroma of coffee.
1st session: How to incubate local brewed robotics by the youth? (11.9.2021)
In shopping malls, you might meet the cute robots - Rice who delivered your meal, or Jasmine who helped disinfection. In this session of Science Cafe, the guest speaker shared about the journey in developing these local brewed robots.
Guest speaker: Ms. Sophiya Chiang (Head of Product and Technology, Rice Robotics Limited)
2nd session: How to conserve the beautiful corals in Hong Kong? (18.9.2021)
Like to dive overseas? Did you know that the underwater world of Hong Kong is so vibrant? You couldn't imagine the reproduction of corals once in a year is so breathtaking. In this session, the guest speaker shared with us the magnificent coral colonies in Hong Kong and the way to conserve the beautiful local corals.
Guest speaker: Prof. Apple Chui (Research Assistant Professor, School of Life Sciences, The Chinese University of Hong Kong, and Founder of Coral Academy)
3rd session: How to forecast the ever-changing weather? (25.9.2021)
Do I need to bring an umbrella today? Is it true that it will rain for three days for a missed typhoon? In this session, the guest speaker shared with us the keys to weather forecast and the use of MyObservatory app to plan our itineraries ahead to tie in with the weather conditions.
Guest speaker: Dr. Andy Lai (Scientific Officer, Hong Kong Observatory)
QKPOST: Listening - Science100 Ω
The Science Promotion Unit (SPU) and the Listening Team interviewed 100 "Life Scientists" about their views towards science.
How can science help us solve problems in our daily lives? What makes science fun and interesting? In this episode "Listening – Science100Ω", we can learn about the in-depth thoughts of "Life Scientists" on science.
QKPOST: Science Vocabulary A to Z - J for Joule
What does joule mean? Joule, abbreviated as J, is the international unit of energy which is named after the famous physicist James P. Joule.
Given that energy is convertible, according to historical and traditional measurement methods, energy can be represented by different units, including British thermal unit (Btu), calorie (cal), kilowatt hour (kWh) and joule (J), to meet different needs. So what exactly is one joule?
One joule is defined as the amount of energy exerted when a force of one newton is applied on an object which moves a distance of one metre in the direction of the force.
Don't worry! Just pay more attention to energy-related things around and you will understand the use of different units easily.
So, do you know what unit is used for energy consumption as indicated on the energy labels of electrical appliances?
QKPOST: Listening - Science100 α
What is "Science"? How does science connect with our lives? What is your impression of scientists? If you were a scientist, what would you like to invent?
The Science Promotion Unit (SPU) and the Listening Team interviewed 100 "Life Scientists". Let's listen to their views towards science together!
QKPOST: Science Vocabulary A to Z - I for Immune System
The immune system is the body's lines of defence against diseases. Human immune system is a sophisticated system orchestrated by different types of cells and organs. It can detect and destroy foreign invaders, such as bacteria, viruses and pathogens.
The immune system can be classified into innate immunity and acquired immunity. The innate immune mechanisms are physical and chemical barriers that are always ready to defend the body from pathogens, such as skin, lysozymes in saliva and leucocytes. The acquired immune responses occur only after exposure to a specific pathogen either by infection or vaccination. It is tailored to fight against a specific pathogen, such as the new coronavirus causing the ongoing global pandemic.
In addition, allergies such as reactive airway disease, allergic rhinitis or food allergy are also related to the immune system. Allergies are caused by a type of antibody called Immunoglobulin E (IgE), which binds to mast cells in the skin, trachea, digestive tract, etc. When IgE detects an allergen, it will activate the mast cells to release histamine and trigger allergic symptoms in the body.
Do you know how allergy medicines work?
QKPOST: Science Vocabulary A to Z - H for Hydrocarbon
Hydrocarbon is an organic compound composed solely of the elements carbon (C) and hydrogen (H). Different numbers of carbon and hydrogen atoms combine to form an endless number of hydrocarbons on Earth.
One carbon and four hydrogen atoms form methane (CH4), the main constituent of natural gas. Two carbon and four hydrogen atoms will combine to form ethylene (C2H4), which is produced during the ripening process of bananas. If we place a ripening banana next to an avocado, the avocado will be ripened and become soft. Fossil fuels such as the gasoline, diesel or liquefied petroleum gas refined from oil are mainly composed of hydrocarbons as well.
Do you know other uses of hydrocarbons in our daily lives?
QKPOST: Science Vocabulary A to Z - G for Gravity
Last time, we mentioned the four fundamental forces in the universe, and today we are going to introduce gravity.
Gravity is an attractive force between all objects with mass. Under its action, tides occur, Moon orbits around the Earth, the Earth orbits around the Sun and substances in the universe can be pulled together to form new stars and planets.
It is well-known that people and objects are kept on the ground because of the Earth's gravity. In fact, our bodies are exerting attractive forces on the Earth. However, the Earth is much massive, so we cannot observe the effect. Gravity is a relatively weak force. Hence, we can resist it to lift up a cup by applying a gentle force.
Do astronauts escape from the Earth's gravity when they fly into space?
QKPOST: How is silky chocolate made?
Thinking of making chocolate at Christmas, and wondering how to make chocolate that is smooth, crunchy and shiny? Tempering is the key!
Cocoa butter is the major fat component in chocolate. At different temperatures, it will have different forms of crystal. The denser cocoa butter molecules are stacked together, the more stable the crystal structure will be, resulting in higher melting point and harder texture.
Tempering refers to the heating and cooling of chocolate at optimal temperatures. One of the crucial factor is not to heat up the chocolate directly, but to melt it in a hot water bath at the right temperature. This promotes the formation of ideal crystalline structure and produces chocolate that is shiny with smooth texture and melts only in your mouth but not in your hand.
Have you tried to temper your chocolate?
QKPOST: How do leaves dress for fall?
Autumn is a perfect time for leaf peeping, especially when leaves start turning red! However, not all leaves turn red in late autumn.
The most common tree with red leaves in Hong Kong is the Sweet Gum. Its leaves contain a variety of pigments, including green chlorophyll, yellow carotene and red anthocyanin, etc. In spring and summer, when the weather is warm with strong sunlight, photosynthesis is very active and there is more chlorophyll in the leaves than other pigments. So the leaves appear green.
In autumn and winter, with less sunlight and lower temperature, the effectiveness of photosynthesis is reduced. The nutrients and nitrogen in the leaves are transferred to the roots and stems. The green chlorophyll degrades gradually, so the yellow carotene and red anthocyanin become more prominent. Therefore, the leaves turn to yellow and red.
Other than sweet gum, do you know of any other trees with red leaves in Hong Kong?
Tips for red leaves peeping:
To grasp the best time for enjoying red leaves scenery, you may check for Agriculture, Fisheries and Conservation Department's red leaves index of Tai Tong Sweet Gum Woods before making your trip:（https://www.natureintouch.gov.hk/redleaves）
QKPOST: Science Vocabulary A to Z - F for Force
When we speak of force, we may relate it to attraction, influence, strength or weakness. In fact, force is everywhere in our daily lives. Force can change the state of motion of an object, including its speed, direction and shape. However, scientists do not treat force so simply. Physicists study all phenomena and conceive that all forces in the universe can be classified into four fundamental forces, namely strong force, weak force, gravitational force and electromagnetic force.
Oh! Confused with so many kinds of force? Don't worry! We will explore the science of force with you later.
QKPOST: What is the science behind figure skating?
"To Science With Love" Microfilm: Ice Breaking
Figure skating is an elegant and beautiful sport. Working in an ice rink, the actress in the microfilm often tries to learn figure skating by herself after work. But no matter how hard she tries, she still can't grasp the professional spinning techniques. Why? Watch the video and find out how science inspires the actress to perform graceful figure skating movements!
QKPOST: How do science recreate a flavour of the past?
"To Science With Love" Microfilm: Expiry Taste
Did you know other than ingredients, science also plays a big part in creating delicious cuisine? The actress in the film is a head chef. In order to satisfy a "mysterious guest", she works hard to improve a signature dish Dragon Home. How does she create a rich starchy sauce? How to make the flavour even more appealing? Watch the video and find out how science can help create a flavour of the past!
QKPOST: Science Vocabulary A to Z - E for Evolution
Have you ever heard of "Survival of the fittest"? This is a phrase originated from Darwin's evolutionary theory!
So what exactly is evolution? It refers to the change in the inherited traits of organisms through generations. It originates from genetic variations within a population. Taking human as an example, inherited traits such as skin colour, blood type and height vary from person to person. In nature, if some individuals possess some traits that allow them to have an edge for survival, they are more likely to reproduce and pass the adaptive traits to their offspring. Vice versa, individuals with less adaptive traits are less likely to survive and reproduce. As time goes by, those adaptive traits will become more prevalent, and hence bring new species.
To obtain greater survival advantage, some animals can blend in perfectly with the environment, click the link below to learn more about these incredible animals:
Other than these animals, do you know other organisms with special adaptive traits?
QKPOST: Which is more important: the process or the result?
"To Science With Love" Microfilm: Tuesday's Invention
Which is more important: the process or the result? In the journey of scientific research, even if scientists experience repeated failures, they will never give up! They have to learn from failures, and keep fighting against all odds before they can succeed.
In the video, the main character Felix is obsessed with scientific inventions, and he is often laughed at and rejected by his classmates. However, he observes the spirit of scientists and does not give up. Let's see if he can succeed in the end!
QKPOST: So… What is Science?
What comes to your mind when you hear the word "Science"? Albert Einstein? Solar torch? Or space travel? While it sounds so remote, in fact, science is like your friends, all around you and no stranger at all!
Themed on toys, food and ice skating and with touching storylines, "To Science With Love" microfilm series brings out that science can be approachable and humane.
Let's take a sneak preview and check out what people think about science, and how the three micro-films move our Museum Director!
QKPOST: How is the automatic door related with Einstein?
This year marks the 100th anniversary of Einstein's Nobel Prize in Physics. Speaking of Einstein, many people will think of the theory of relativity, but this genius scientist won the award that year actually because of photoelectric effect!
The photoelectric effect refers to the emission of electrons when an object is hit by light. To produce this phenomenon, the light must have sufficiently high energy. However, classical physics cannot fully answer the questions involved in this phenomenon. Einstein put forward the concept of modelling light as particles (photons) and successfully explained the photoelectric effect. The electron absorbs the energy of the photon, which is related to the frequency of light. Only if the photon has sufficient energy, which means the frequency is high enough, will the electron has enough energy to be free from the attraction of the material.
Some automatic doors make use of the photoelectric effect. These doors are installed with light emitters and light sensors. When we approach the door and block the light from the light sensor, the current will drop. By detecting the change in current and incorporating proper circuitry, the automatic door will open.
Do you know of any other applications of the photoelectric effect?
The winner of this year's Nobel Prize in Physics has been announced! Congratulations to Syukuro Manabe of USA, Klaus Hasselmann of Germany and Giorgio Parisi of Italy for groundbreaking contributions to our understanding of complex physical systems!
QKPOST: Science Vocabulary A to Z - D for DNA
Deoxyribonucleic acid (DNA), is the genetic material that can be found in cells and governs the unique traits of living things. Composed of four nucleotides represented by A, T, G, C, it forms a double helix structure.
Each individual has its unique genes. What is the difference between DNA and gene? A gene is a part of the DNA sequence with unique order of nucleotides. If DNA is a spiral staircase, nucleotides are the steps and a gene is a part of the spiral staircase. Our size of the earlobe, the ability to roll our tongue etc. are all related to genes.
We now know the difference between DNA and genes, how are they related with chromosome?
QKPOST: Science Vocabulary A to Z - C for Cell
Cell is the basic unit of living things, and we have tens of trillions of cells in our body. An animal cell is mainly made up of cell membrane, cytoplasm, organelles and genetic materials.
A cell operates like a city. Cell membrane is the port of entry, controlling what goes in and out of a cell. Cytoplasm is the living environment of a city, which is jelly-like and provides a stable working environment for organelles. Organelles are the buildings with different functions. The cell nucleus is the control centre responsible for storing and replicating genetic materials and giving instructions for normal functioning of the body.
Do you know what living organisms in our body are more numerous than our cells?
QKPOST: Why drinking coffee can be refreshing?
Coffee can keep us awake because of caffeine, but why is that? It's actually a misunderstanding of our brain!
Adenosine is one of the chemicals that makes us feel sleepy. When its level rises, it will bind with more adenosine receptors in our brain and make us feel sleepy. The structure of caffeine is similar to adenosine. When we drink a cup of coffee, caffeine will bind with adenosine receptors and hence prevents adenosine from binding with them. As a result, the detectable level of adenosine will be reduced, and that's why caffeine can keep us awake.
However, the effectiveness of caffeine varies from person to person. Some people still feel sleepy after drinking a big cup of coffee, whereas others can't fall asleep even with only a few sips. This is because of the genetic variation, so that some people's adenosine receptors won't bind with caffeine easily. Hence, caffeine will not work on them as effectively!
Other than coffee, can you name other food or drinks that contain caffeine?
QKPOST: Why coffee smells so good?
A cup of coffee makes a good day perfect. Have you ever wondered why coffee smells so good?
To brew a cup of aromatic coffee, we will need coffee beans and they are the seeds of coffee trees. If we remove the pulp and skin of a coffee cherry, we will find the green coffee bean (the seed). When green coffee beans are roasted under high temperature, they become coffee beans.
The high temperature of roasting triggers a number of chemical reactions in the green coffee beans, for instance, the pyrolysis of sugars will produce caramel compounds (caramelisation), and with the presence of carbohydrates and proteins (that is reducing sugars and amino acids), Maillard reaction will take place and produce a variety of aromatic compounds and melanoidins, forming the unique colour and aroma of coffee!
Do you know why we feel refreshed after drinking coffee?
QKPOST: Science Vocabulary A to Z - B for Big Bang
Many of us are familiar with the Korean boyband "Big Bang", but do you know anything about the "actual" Big Bang?
Scientists believe that the universe was formed from the Big Bang. According to the Big Bang theory, 13.8 billion years ago, all matter and energy in the universe were squeezed into a "singularity", which is a very dense and extremely hot point.
At the moment of the Big Bang, time began. The four fundamental forces, including the gravitational force, the strong force, the weak force and the electromagnetic force were separated. After continuous expansion and cooling, various elements were gradually formed. Under the gravitational attraction, matters clump together, forming stars and galaxies, gradually becoming the universe today.
Then what is the difference between the Big Bang and an ordinary explosion?
QKPOST: Colour Series - Carmine as food colouring
Sausages, hams, crab sticks, etc. are all red in colour. The common "red" processed food we come across in our daily lives may have used a type of edible red food colouring called "carmine". Have you ever thought about that it is produced from cochineal insects?
Using insects to make food sounds scary, right? Cochineal insects are native to South America and Peru is the major supplier of carmine. The insects feed on cactus and their bodies contain the red carminic acid which deter predators.
The carmine production process is as follows: dry and ground the insects, put the extracts into hot water with addition of ammonia or bicarbonate and precipitate with aluminium salts, then wash with water and sterilise. Carmine can appear from orange yellow to purplish red at different pH level.
Carmine is a stable natural colouring which is resistant to light and heat and can be used in cosmetics besides food. Carmine is safe for most people but a few people may be allergic to it.
How can we tell which food contains carmine? Food labels listed 120, E120, Cochineal, Carminic acid, Carmines or Natural Red 4 all indicate that carmine is used.
Will you consider to eat sausages in green colour or crab sticks that are yellow? Can you think of other ingredients that could produce red natural colouring?
QKPOST: Science Vocabulary A to Z - A for Atom
"It's a small world after all. It's a small world after all…"
Atoms are the basic building blocks of all matter. For example, H2O or water molecules are made up of two hydrogen atoms and one oxygen atom. Although atoms are all around, how do they look like actually?
IBM researchers produced a micro micro film magnifying atoms 100 million times with carbon monoxide, consisting of carbon and oxygen atoms, as the leading actors. It won the smallest stop-motion film in the Guinness World Records.
Enjoy a truly micro micro film here:
Do you know what is inside an atom?
The launch of QK POST! (17 August 2021)
Special announcement: The Hong Kong Science Museum has recently established the Science Promotion Unit, with Curiosity, Collaboration, Creativity and Playfulness as our core values. By sharing interesting science content and ideas around a range of daily-life topics, we encourage everyone to explore the incredible world of science.
QK POST is our first programme. "QK" stands for "Quest for Knowledge". We hope to share various scientific knowledge through online platforms. Stay tuned for our latest news!