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Science Focus by HKUST

🌸A science magazine published by the School of Science at HKUST Science Focus is a science magazine published by the School of Science at HKUST.

Specially written and designed by HKUST science students under the guidance of School of Science faculty and staff, Science Focus is offered free-of-charge to Hong Kong secondary school students, three issues per annum. Email: [email protected]

We welcome your feedback. School of Science affiliate pages:
LIFS Human Genetics Workshop: https://www.facebook.com/humangenetics.hkust/

30/12/2025

《甚麼是無線射頻識別？📶》
What Is Radio Frequency Identification?

RFID是「無線射頻識別」的英文縮寫，亦是八達通、學校通行證及許多信用卡採用的技術。

RFID系統使用無線電波在標籤和讀取器之間進行通訊。讀取器透過發射無線電波為被動標籤以電磁感應原理供電，標籤則透過反射經修改而包含其資料的訊號回應，供讀取器對其進行解碼。

也有一些以電池驅動的主動標籤，它們會定時對外發送自己的識別資訊，通訊距離較遠。部分標籤中儲存的資訊更是可覆寫的。

RFID is the abbreviation for “Radio Frequency Identification.” It's the technology used by your Octopus card, school access pass, and many credit cards.

RFID systems use radio waves to communicate between tags and readers. A reader emits radio waves to power passive tags by electromagnet induction. The tag then responds by reflecting a modified signal containing its data for the reader to decode.

There are also active tags powered by a battery that periodically transmits its identification information through a longer distance. Some tags are rewritable so that its stored data can be overwritten.

By .___ (on IG) & Audrey

06/11/2025

《保護兒童的設計：任天堂的苦味卡匣🎮》
Child-Proofing by Design: Nintendo's Foul-Tasting Cartridge

幼兒會將物品放入口中，是因為這是他們認識和與世界互動的基本途徑。我們該如何守護他們遠離潛在危險呢？

任天堂Switch遊戲卡匣僅有成人拇指指甲大小，使它們對兒童構成嚴重的窒息風險。

任天堂選擇在卡匣表面鍍上世界已知最苦的化合物 ── 苯甲地那銨，以這種無毒化合物降低窒息風險。

苯甲地那銨在極低濃度下也會產生劇烈苦味，能瞬間觸發作嘔反射，使孩童吐出物件，更能避免他們再次放卡匣到口中。

Toddlers put things in their mouths because it's their basic way of learning about and engaging with the world. How can we protect them from potential danger?

The Nintendo Switch game cartridges at the size of an adult thumbnail can pose a serious choking hazard to children.

To reduce the risk of choking, Nintendo coats the cartridges with non-toxic denatonium benzoate, which is known to be the world's most bitter compound.

Denatonium benzoate is extremely bitter at very low levels, triggering instant gag reflex and rejection. It makes a child spit the cartridge out immediately and discourages repeated attempts.

By .___ (on IG) & Audrey

27/10/2025

第三十一期《科言》出版啦！😄

您可以在科大何廷錫伉儷訪客資訊中心或SCI/HOME領取實體版《科言》，亦可瀏覽電子版：https://ebookshelf.hkust.edu.hk/flippingbook/G23596/

《科言》是由科大理學院學生參與撰寫及設計的免費科學雜誌，每期會派送到多達140間中學，歡迎中學老師為學生訂閱。

Science Focus (Issue 031) is out! 😆

Printed copies are available at Mr & Mrs Ho Ting S*k Visitor Information Center or SCI/HOME at HKUST campus. E-book can be viewed at https://ebookshelf.hkust.edu.hk/flippingbook/G23596/.

Science Focus is a magazine published by the School of Science, HKUST. It is prepared by our undergraduate students and offered free of charge to everyone. We have been delivering our magazine to 140 secondary schools. Interested teachers are welcome to subscribe for your school.

16/10/2025

《步行對我們的健康有益嗎？🚶‍♀️》
Is Walking Beneficial to Our Health?

研究顯示，居於步行友好社區的香港長者，相較於生活在步行便利度較低區域的長者，不僅生活滿意度更高，孤獨感也顯著降低。這項發現凸顯行人友善的城市設計對心理健康的價值。

步行是一種簡單卻強大的運動，能帶來重要的健康益處。研究證實，適度增加每日步數可改善心血管健康、強化骨骼，並減輕焦慮與憂鬱。

為獲取健康效益，建議每週多數日子進行30分鐘快走，步速應達到能說話但無法唱歌的程度，儘管可能會伴隨輕微氣喘。

將運動融入生活是保持健康的良策。可以嘗試以樓梯取代電梯，提早下車，結伴步行，或是遛狗以建立步行習慣。

Hong Kong seniors report elevated levels of life satisfaction and reduced loneliness when they live in walkable neighborhoods versus less walkable ones, underlining the mental health value of pedestrian-friendly urban design.

Walking, a powerful yet simple exercise, provides major health benefits. Research confirms that modestly increasing daily steps improves cardiovascular fitness, strengthens bones, and reduces anxiety and depression.

Walk briskly for 30 minutes most days to reap health benefits. At this pace, you can talk but not sing, and you'll likely be puffing a bit.

Making physical activity a seamless part of your lifestyle is a top strategy. To build walking habits, try using stairs instead of elevators, alighting transit early, walking with friends, or walking your dog.

By .___ (on IG) & Audrey

02/10/2025

《藍冰和白冰有甚麼分別？🧊》
What is the difference between blue ice and white ice?

藍冰的形成是由於雪和冰層被壓縮，擠出空氣氣泡，產生密度較高的冰。藍冰會吸收波長較長的光（例如紅光和橙光），並散射藍光，使冰體呈藍色。

白冰形成於快速結冰的水，尤其在有風或浪的情況下。由於困住的空氣能散射所有顏色的光，因此白冰呈白色及不透光。

白冰較易碎裂，因此在湖面溜冰或駕駛雪地電單車前應評估冰面的類型和厚度，以策安全。

Blue ice forms when snow and ice are compacted, squeezing out air bubbles. The resulting dense ice appears blue because it absorbs light at longer wavelengths (e.g. red and orange) and scatters blue light.

White ice forms when water freezes rapidly, especially under turbulent conditions (like wind or waves). White ice appears white or opaque because the trapped air scatters all colors of light.

White ice is more prone to fracturing. Therefore, for safety, do assess the type and thickness of ice before skating or riding a snowmobile on a lake or pond.

By .___ (on IG) & Audrey

18/09/2025

《為甚麼蘋果切片會變成棕色？🍎》
Why do sliced apples turn brown?

蘋果切開後，果肉接觸到空氣中的氧氣，會使多酚氧化酶開始催化多酚氧化的過程。這個酶促反應產生鄰醌（o-quinones），其及後與胺基酸結合後，會形成褐色的黑色素（melanins）。

由於不同品種的蘋果所含的酶和多酚多寡不一，所以切開後變黃的速度也不一樣。

蘋果切片後保持新鮮的秘訣：
❄️ 冷藏降溫 → 降低酶活性
🍋 與檸檬汁混合 → 透過降低pH以降低酶活性，並讓檸檬中的抗氧化成分發揮作用！
🍯 愛甜口？裹上一層蜂蜜、焦糖或糖漿 → 隔絕氧氣超有效

When an apple is cut, the apple's flesh is exposed to oxygen, which triggers the oxidation of polyphenols by the enzyme polyphenol oxidase. This enzymatic reaction produces o-quinones, which subsequently react with amino acids to form brown melanins.

Different apple varieties contain varying levels of the enzyme and polyphenols, so they brown at different rates.

To keep apple slices fresh:
❄️ Chill them → reduce enzymatic activity
🍋 Toss them in lemon juice → reduce enzymatic activity by lowering pH, and let the antioxidants of lemon work!
🍯 For a sweeter fix, coat them in honey, caramel, or syrup → physically block oxygen

By .___ (on IG) & Audrey

09/09/2025

✨We’re Recruiting! 📢

Do you want to join our efforts to popularize science?
Or be a future graphic designer or content creator?
…Here comes the chance that you shouldn’t miss! 😃

We are looking for HKUST science undergraduate students to prepare contents for the print magazine and social media pages, under the supervision of staff and faculty from the School of Science.

For details, please refer to the email dated September 9, 2025 (Tue). The application deadline is September 21, 2025 (Sun).

Should you have any enquiries, please direct them to [email protected]. 📧
-----⠀⠀

21/08/2025

《甚麼是無乳糖產品？🧀》
What are lactose-free products?

無乳糖乳製品讓乳糖不耐症人士也能享用乳製品，但到底怎樣才能生產出這些產品？

要生產無乳糖產品，可以先過濾掉牛奶中40%乳糖，再加入乳糖酶把剩餘乳糖分解成身體可吸收的葡萄糖和半乳糖。

某些乳製品本來就含有較少乳糖，因為這種雙糖會在製作過程中被去除，使部分乳糖不耐症人士也能無恙地攝取。例如車打或高達芝士這類硬芝士中的大部分乳糖在製作過程中會隨著乳清排走，而剩餘的乳糖則被乳酸菌分解，因此每100克芝士僅含低於0.05克乳糖 ── 可說是幾乎不含乳糖！

Lactose-free dairy products cater for the need of people with lactose intolerance. How are they made?

To produce lactose-free products, milk can be first filtered to remove around 40% of lactose. Lactase is then added to break down the remaining lactose into glucose and galactose, which can be absorbed by the body.

Certain dairy products are naturally low in lactose as the disaccharide is removed during the manufacturing process. These products can be consumed safely by some people with lactose intolerance. For example, hard cheeses like Cheddar or Gouda have most of their lactose removed along with whey, and the remaining lactose is metabolized by lactic acid bacteria. Therefore, these cheeses have less than 0.05 g lactose per 100 g – practically lactose free!

By .___ (on IG) & Audrey

07/08/2025

《甚麼是乳糖不耐症？🍼》
What is lactose intolerance?

乳糖不耐症患者無法消化乳糖，進而可能在攝取奶類後腹瀉和腹脹。

在理想的情況下，乳糖酶會將乳糖分解為葡萄糖與半乳糖，然後這些單糖經腸道內壁吸收至血液。

乳糖不耐症成因是小腸在成年後無法製造足夠乳糖酶。這是一個常見的情況，因為只有北歐和印度西北部的人保留在成年後消化乳糖的能力。

未被分解的乳糖進入結腸，因水勢緣故將水份從血液抽至腸道，同時腸道細菌能分解乳糖並產生氣體，造成腹瀉和肚痛等不適。

Lactose intolerance is the inability to digest milk sugar, possibly resulting in diarrhea and bloating after dairy consumption.

Ideally, lactase breaks down lactose into glucose and galactose. These monosaccharides are absorbed via the intestinal lining into the blood.

Lactose intolerance occurs when the small intestine doesn't produce enough lactase after reaching adulthood. This is a common condition because only Northern Europeans and Northwestern Indians retain the ability to digest lactose.

The undigested lactose moves to the colon and draws water from the bloodstream due to osmotic pressure. Gas is also produced when the lactose is broken down by gut bacteria. These can cause diarrhea and abdominal pain.

By .___ (on IG) & Audrey

24/07/2025

《隱形眼鏡護理液知多點 👁️》
A Guide to Contact Lens Solutions

隱形眼鏡護理液主要有兩種：雙氧水和多用途溶液。它們的區別在於消毒方式的不同。

雙氧水使用過氧化氫（H2O2）作為消毒劑，濃度通常為 3%。隱形眼鏡盒中的鉑、鈀或銀等催化劑可以加速降解對眼睛有害的過氧化氫，使其分解為水和氧。

多用途溶液通常含有聚己亞甲基鹽酸或聚季銨鹽-1等消毒劑，兩者均能阻礙細菌增長。

其他成分如雙磷酸鹽（bisphosphonates）有助分解鏡片配戴時累積的蛋白質，而保濕與護理化學成分則能確保鏡片在存放期間維持良好狀態。

溫馨提示：潤眼液和隱形眼鏡護理液因成分不同，所以不能把其看待成相同東西交替使用。

There are two main types of contact lens cleaning solutions: peroxide solutions and multi-purpose solutions. They differ by the way they disinfect.

Peroxide solutions utilize hydrogen peroxide (H2O2) as a disinfectant, typically at 3% concentration. The catalyst present in the contact lens case, such as platinum, palladium or silver, can speed up the degradation of harmful peroxide into water and oxygen.

Multi-purpose solutions typically contain disinfectants such as polyhexamethylene biguanide or polyquaternium-1, both of which can inhibit bacterial growth.

Other compounds such as bisphosphonates help break down proteins that accumulate on the lens during wear, while moisturizing and conditioning chemicals ensure good storage conditions.

A final reminder: Eyedrops and contact lens solutions cannot be used interchangeably due to their different compositions.

By .___ (on IG) & Audrey

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Office Of The Dean Of Science, The Hong Kong University Of Science And Technology, Clear Water Bay
Kowloon

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https://sciencefocus.hkust.edu.hk/

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Science Focus is a science magazine published by the School of Science at HKUST. Specially written and designed by HKUST science undergraduate students under the guidance of our faculty and staff, Science Focus is offered free-of-charge to Hong Kong secondary school students, two to three issues per annum. The aim of the magazine is to stimulate and nurture students’ interest in science and scientific research through interesting articles. Email [email protected] We welcome your feedback. School of Science affiliate page: LIFS Human Genetics Workshop: https://www.facebook.com/humangenetics.hkust/