Science Focus = 科言, Issue 012, 2017

All about

Nuclear Fusion

㛶优婈䚣⟘⫏

“Bird Brain”?

Ravens Think Otherwise

⃣⫍䗉㳟毇濊殣朜䕂䭼㓌ᵢ㓑仃

Scramble for Sand

㱆⟯䕂㭗宅㵎

From Physics to Biology:

Interview with Prof. Yifan Cheng

⹜䄧䋄⃮䏝䄧µµ⫆壨䣉ᵤ₟㐗㉆

Issue 012, 201

7

Dear Readers,

Welcome to the twelfth issue of Science Focus! People often associate winter weather with colds. Your parents may tell you to avoid getting a cold by keeping yourself warm. Is it true that cold weather makes you catch a cold? It is up to debate. In this issue, one of our articles looks into this “Cold Case”. This article, along with another article on nuclear fusion, is taken from our Student Web Blog. They are among the most popular pieces on the website. For more great science articles, check out the website http://sciencefocus.ust.hk.

Apart from these two articles, this issue also covers hot topics such as wireless charging and the scarcity of sand resource. Do not forget to check them out!

If you are interested in science and writing, please do not hesitate to send your science article to us! Selected articles will be published and you may have a chance to win an iPad. You may visit our website for more details.

Enjoy your Science Focus! Yours faithfully,

Prof. Yung Hou Wong Editor-in-Chief 妑㄂䙫孧俬Ɲ 㭈徵斘孧䬓⌨ṳ㜆ˣ䦸姧ˤƄ὇䙫⮝ạㇽ㛪㎷慹὇Ə✏↓⤐奨⤁ 㳏ヶῄ㙽˛↓⤐䙫⤐㰊⽧⽧ịạ偖ペ∗₞梏˛⮹↞⤐㰊㘖␍䜆 䙫㛪ịạりᷱ₞梏Ƣ䬻㠯凚ằẴ㛰䈔字˛ằ㜆ˣ䦸姧ˤ䙫⅝Ḕᷧ 䮮㕮䫇ᾦ㎉姵ṭ怀ᷧ媑㲼˛怀䮮㕮䫇⑳ằ㜆⏍ᷧ䮮旃㖣㠟偁孱 䙫㕮䫇Ə惤㘖⇡凑ㇸῸ䶙䫀䙫⭟䔆惏吤㠣Ə✏䶙䫀ᷱ䛟䕝⎾孧 俬▃㄂˛⥩㞃὇㛰凯嶊斘孧㛛⤁⭟䔆惏吤㠣䙫䲥⽐䦸⭟㕮䫇Ə ⏖∗ㇸῸ䙫䶙䫀䛲䛲ƝKWWSVFLHQFHIRFXVXVWKN]KKN˛ 晋ṭỌᷱ㎷∗䙫⅐䮮㕮䫇Əằ㜆ⅎ⮠ẍ㶜咲ṭᷧẂ䆘敧字栳Ə ὲ⥩䄈䷁ℬ曢⑳㲀岮㹷䟔伡˛〉吓ᷴ奨挖怵怀Ẃ䲥⽐㕮䫇Ƅ ⥩㞃὇⯴䦸⭟⑳⯒ὃ㛰凯嶊ƏㇸῸ媇恧὇⎪⊇˥䦸姧⾜㕮㮻 峤˦˛墒恟Ḕ䙫ℑ䦧ὃ⒨⯮㛪⇱䙢✏ˣ䦸姧ˤ曃婳Əḍ㛪㛰㩆㛪 島⽾ L3DG ᷧ惏˛婚ガ⏖⎪䛲ㇸῸ䙫䶙䫀˛ ⷳ㜂὇▃㭈ằ㜆ˣ䦸姧ˤƄ Ḣ䷏䍲㮞⎁㕀㍯ 㕓ᷱ

Message from the Editor-in-Chief

Ḣ䷏婘媅

Copyright © 2017 HKUST E-mail: [email protected] Homepage: http://sciencefocus.ust.hk

Scientific Advisors䢏⨶朥␍ Prof. Simon Chan 攱新㐗㉆ Prof. Karl Herrup

Dr. Ice Ko 榖⾞∘➩

Prof. Kam Tuen Law 乃懤◖㐗㉆ Prof. Pak Wo Leung 㜿ᷭ⍊㐗㉆ Prof. Shing Yu Leung 㜿ㄽ垓㐗㉆

Editor-in-ChiefḢ䷏弖

Prof. Yung Hou Wong䉉㩵≘㐗㉆

Associate Editor≖䷏弖

Prof. Ho Yi Mak浣㔥⻟㐗㉆

Managing Editor两䷏弖

Janice Wong 䉉㧡㧡

Student Editorial Board ⨶䏝䲦⢒

Editors䷏弖

Long Him Cheung ⷳ㗕姗 David Iu⢘奞氞

Thomas Lee㘌㰧宠 Twinkle Ching Poon 㸖㔲 David Ren ᶹ⟥ἇ

Reporter姿俬

Teresa Ming Shan Fan㣈慖⢕

Graphic Designers娔姯⸒

Rinaldi Gotama 㘌Ⓡ⹵ Steve Min Kyu Park Tommy Wong 涁㝑姗 What’s Happening in Hong Kong? 桗㳭䢏ㄾ㯹↓

The Shaw Prize 2017 Exhibition 1  悜怟⤒䌵ⰼ妤

Aurora at Space Museum ⤑䩡椏䙫㥜ℰ

Hong Kong Black Kite Festival and Hong Kong Raptor)HVWLYDO

榀㸖溢淠䮧㚏榀㸖䌂䦤䮧 Science in History 㓒㒣䢏⨶

Maryam Mirzakhani: the Female Mathematician 2 Who Made History ≜怇㭞⏙䙫⥚㕟⭟⮝ă䑑湾⭰ 澽 䱚䈥㜔⒯Ⱓ

Science Today ᶈ㒣䢏⨶

“Bird Brain”? Ravens Think Otherwise 4 ∌⯶䛲㸈泰Ƅ泌桅䙫䲥㗵ẋ㗺俬

Scramble for Sand 6 㵯⤘䙫㲀岮㹷

A Cold Case 8

˥吾㶣˦䜆㛰⅝ṲƢ

Amusing World of Science 䢏⨶屡ᵉ

All about Nuclear Fusion 10 㠟偁孱䟌⤁⯸

The Wireless World 14 䄈䷁䙫᷽䔳

The Physics of Poop: Why It Matters 16 ⤎ᾦ䦸⭟ṳᷰṲ

Perfume: the Chemistry of Attraction 18 榀㰛䙫䦿⮭

Who’s Who?䢏⨶Ⲧᵸ

From Physics to Biology: Interview with 20 Prof Yifan Cheng

⾅䉐䏭∗䔆䉐ă⯯娑䧲ẍ⇈㕀㍯

Acknowledgements䄷⃣殲姛

Contents

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෫

ऋ

׬

ࣀ

ଢ଼

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WHAT’S HAPPENING IN HONG KONG ?

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Fun in winter science activities

Any plans for the Christmas and New Year holidays? Check out these science activities!

⨡䕂䢏⨶⠻䩾䖬

壆⅁⠻伔奓䩾⍊㑮ⴲ䕂⠻≹唓ᵄ⒌濨᳋⡦仁〬ᶣ᳉㯹↓濊

The Shaw Prize 2017 Exhibition

E s ta b l i s h e d i n 2 0 0 2 , t h e S h a w P r i ze recognizes scientists with recent significant breakthrough in scientific work. It consists of 3 annual prizes: Mathematical Sciences, Life Science and Medicine, and Astronomy. In the exhibition, you can learn more about the 2017 Shaw Laureates and their scientific research.

Venue: Science News Corner, Hong Kong Science Museum Date: now – 27/12/2017

Aurora at Space Museum

Screening of the Sky Show “KAGAYA’s Aurora” will end in January, so grab the chance to see “aurora” in Hong Kong while you can!

Screening date: now – 31/1/2018 For details, please visit

http://goo.gl/HC8G12

Hong Kong Black Kite Festival

and Hong Kong Raptor Festival

We can see the black kite everywhere in Hong Kong. However, do you know that Hong Kong has the highest density of the black kite around the world? The Festival held by Eco-Education & Resources Centre is going to show you the key features of the birds and the

conservation situation with interactive a cti vit i es. Pl ea se s ta y t un ed to announcements from the Facebook page of the Centre for details.

彳延⟩䈌⬓塻

˥悜怟⤒䌵˦㖣⹛娔䪲Ə娔㛰ᷰῲ䌵柬Ɲ㕟⭟ 䦸⭟䌵˚䔆⑤䦸⭟凮憒⭟䌵⑳⤐㕮⭟䌵Ə⇭∌柹䙣䵍 ✏䛟旃⭟堺柿⟆㛰⁸⇡岉䍢ㇽ✏徸㜆㛰䩨 䠛『ㇷ㞃䙫䦸⭟⮝˛忶怵ằ㬈ⰼ妤Ə὇ ⏖Ọ㛛㷘⅌婴嬿ằ⹛䙫⽾䌵俬Ọ⎱ẽ Ὸ䙫䦸䟻ⷌὃ˛ ✗滅Ɲ榀㸖䦸⭟椏䦸姱⺱ ⰼ㜆Ɲ凚㛯㗌



⟨䤸柦䕂㠳 

⤑䩡椏⤐屈䮧䛕ˣ⤉⹢㥜ℰˤ䙫㘇㜆⯮㖣ᷧ㛯䴷 㝆Ə姿⽾㉱㏈㩆㛪∗⤑䩡椏Əᷴ奨挖怵✏榀㸖㬊峅 ˥㥜ℰ˦䙫㩆㛪Ƅ 㘇㜆Ɲ䏥✏凚⹛㛯㗌 婚ガ媲⎪斘䶙✧KWWSJRRJO+&*

桗㳭浹沷䩾㕦桗㳭䇙䡻䩾

溢淠✏榀㸖ḍᷴ似奲Ə䄝俳὇䟌怺榀㸖䙫溢 淠⮭⺍✏᷽䔳⏖嫩㕟ᷧ㕟ṳ▵Ƣ䔆ㄲ㕀備⎱岮 㹷Ḕ⾪凰徍䙫˥榀㸖溢淠䮧㚏榀㸖䌂䦤䮧˦⯮ ⊐὇ṭ姊䉇Ὸ䙫䉠⾜⑳ῄ備䊧㲨˛婚ガ媲䕀ヶ Ḕ⾪䙫⯯柨˛ 䌵 ⇭∌柹䙣䵍 㛰䩨

The

Fields Medal is often considered to be the most prestigious award in mathematics, or the mathematics equivalent of the Nobel Prize. For more than 70 years since its inception, the prize had been awarded to men only. That changed in 2014, when Maryam Mirzakhani became the very first woman to receive the prize for her outstanding contribution to abstract geometry [1].

Born and raised in Tehran, Iran, Mar yam Mirzakhani did not aspire to be a mathematician when she was little. Instead, she had a love for words and read avidly, dreaming to become a writer someday. She did not perform well in the mathematics class when she star ted middle school. Her teacher did not consider her particularly talented in the subject either, and she lost interest in it [2]. However, she met another more encouraging teacher the year that followed, and began to perform much better.

At the time when Mirzakhani was in an all-girls high school, there was no other girl participating in the I ranian I nte r national Mathematical Olympiad team. Nonetheless, with the strong support from the principal, Mirzakhani received training in solving mathematics problems and

叙

䈥匙䌵⽧⽧墒婴䂡㘖㕟⭟䔳㛧岇䛂⏴ 䙫䌵柬Əㇽ㘖㕟⭟䔳䙫嫥岄䈥䌵˛凑⅝ㇷ䪲俳Ὥ 䙫急ᷪ⌨⹛敺Ə⽾䌵俬⅏惏惤㘖䔞『˛怀㙖屈䴩 ✏⹛㔠孱Ə䕝⹛Ə䑑湾⭰澽䱚䈥㜔⒯Ⱓ⛇⥠⯴

the Female Mathematician

Who Made History

ഺ അ ᐣ Ѭ ޟ τ ኵ Ᏸ ড়!

ș!

ᅴᝋԊȆԽᅭҒࠤѻ

represented Iran in the 1994 and 1995 International M at h e m at i ca l O l y m p i a d . S h e p e r fo r m e d exceptionally well and won the gold medal in both competitions, even hitting the perfect score in the second year.

M i r z a k h a n i c o n t i n u e d t o s h i n e a s a mathematics talent after wards. Mir zakhani pursued her Ph.D. in Harvard University. In 2004, she received her doctorate for her thesis, which demonstrated a creative way to combine different mathematical tools for studying properties and solving mysteries about abstract geometry. Her doctoral thesis was so impactful that it gave rise to articles in three top mathematics journals. She joined the Stanford University as a professor of mathematics in 2009.

M i r z a k h a n i s p e c i a l i z e s i n t h e o r e t i c a l mathematics, such as Ergodic theory, symplectic geometry and hyperbolic geometry [3]. She once mentioned in an interview that she was particularly interested in hyperbolic geometry. Hyperbolic geometry is different from the geometry that you are used to seeing in secondary school. Usually, when there are a straight line L and a given point P, there could only be one line passing through P

By Long Him Cheung ⷳ㗕姗

MARYAM MIRZAKHANI:

Ph Ph Ph Ph Ph Ph

References ⊁仁宅㑗濣

1) Bridson, M. (2017). Maryam Mirzakhani obituary. [online] The

Guardian. Retrieved from https://www.theguardian.com/ science/2017/jul/19/maryam-mirzakhani-obituary [Accessed 29

Sep. 2017].

2) Clay Mathematics Institute. (2014). Maryam Mirzakhani: ‘The More I Spent on Maths, the More Excited I Got’. The Guardian. Retrieved from https://www.theguardian.com/science/2014/

aug/13/interview-maryam-mirzakhani-fields-medal-winner-mathematician

3) Myers, A., Carey B. (2017). Maryam Mirzakhani, mathematician and Fields Medal winner, dies at Stanford | Stanford News. [online] Stanford News. Retrieved from: http://news.stanford.

edu/2017/07/15/maryam-mirzakhani-stanford-mathematician-and-fields-medal-winner-dies/ [Accessed 29 Sep. 2017].

4) Economist.com. (2017). Orbituary: Maryam Mirzakhani Died on July 14th. The Economist. [online] Retrieved from https://

www.economist.com/news/obituary/21725270-worlds-leading- female-mathematician-was-40-obituary-maryam-mirzakhani-died-july-14th [Accessed 29 Sep. 2017].

that is parallel to L. When it comes to hyperbolic geometry, however, there is an indefinite number of lines passing through P that are parallel to L! While these theoretical concepts may sound abstract or even alien to you, these concepts indeed can vastly help scientists in various fields of study. For instance, Albert Einstein applied hyperbolic geometry in his works about relativity.

You may imagine that mathematicians solve problems one after another by writing on boards or papers at bullet speed. But that is absolutely not the case for Mirzakhani.

The mathematician claimed that she is actually a slow thinker. She described her work as an adventure in a forest – when lost in a forest, you have to gather knowledge to come up with new tricks until you suddenly reach a hilltop and “see everything clearly” [4].

In 2014, Mirzakhani became the first female Fields Medallist for her contribution to abstract geometry, which could be broadly applied to multiple disciplines including dynamics, computer science, and cosmology [1]. Unfor tunately, Mirzakhani passed away at the age of 40 in July

2017 after a 4-year combat against cancer [4]. Mir zakhani is not merely an outstanding scholar who has left incredible results and tools for others to continue to make breakthroughs and discoveries. She is also a role model for women all over the world who are passionate in mathematics or other fields of science. A star in mathematics has faded, but her inspiration remains.

㊤屈⹥Ἴ䙫⁸⇡岉䍢俳ㇷ䂡䬓ᷧῲ䍙⽾叙䈥匙䌵䙫⥚『 >@˛ 䑑湾⭰澽䱚䈥㜔⒯Ⱓ✏ự㛾⾞溸嘔⇡䔆敞⤎˛⯶㘩 Ə⥠ 䆘㄂㕮⬾⑳斘孧Əⷳ㜂ㇷ䂡ὃ⮝Ə俳ᷴ㘖㕟⭟⮝˛Ḕ⭟晵㮜Ə ⥠㕟⭟䙫ㇷ严塏䏥嵞∄ḍᷴ䩨⇡Ə俨⸒ẍᷴ婴䂡⥠㛰㕟⭟䙫 ⤐峍Ə⥠ᾦ⯴㕟⭟⤘⎢凯嶊>@˛⏖㘖Ə䱚䈥㜔⒯ⰣḲ⽳⎾∗ ⏍ᷧἴ俨⸒滺⋜Ə㕟⭟ㇷ严敲⦲䩨棂䌂怙˛⽳Ὥ⥠怙⅌ᷧ敺 ⥚⬷檿ḔƏ䕝㘩ự㛾䙫㕟⭟⥎㝾⌠ℲỊ塏晱㘖˥⅏䔞䏔˦Ə⾅ 㜑㛰ỢἼ⥚⭐⬷⊇⅌ƞ䄝俳Ə䱚䈥㜔⒯Ⱓ䙫㠈敞ᷴ恡棿⊂✗ 㔖㋨⥠Ə⊐⥠㎌⎾㕟⭟⥎㝾⌠Ⅎ䙫姊栳姺䷛˛㛧䴩Ə䱚䈥㜔 ⒯Ⱓㇷ⊆⊇⅌ṭ㕟⭟⥎㝾⌠ℲỊ塏晱Əḍ✏⹛⎱ ⹛䙫⛲暂㕟⭟⥎㝾⌠Ⅎ㮻峤Ḕ⤎㔥䕗⽐˛⥠怊乳⅐⹛䍙⽾憸 䈳Əḍ᷻✏䬓ṳ⹛⎽⽾㻦⇭὚严˛ ⽳ὭƏ䱚䈥㜔⒯Ⱓ∴⽧⒯ὂ⤎⭟㔢孧⍁⣒⭟ἴ˛∗ṭ ⹛Ə䱚䈥㜔⒯Ⱓ䍙柹㍯⍁⣒⭟ἴƏ⥠䙫⍁⣒媽㕮ⰼ䤡ṭ ᷧ䨕⅞≜ヶ˚⵫㖗䙫㖠㲼Ə䴷⏯ᷴ⏳䙫㕟⭟ⷌ⅞Ọ䟻䩝㊤屈 ⹥Ἴ䛟旃䙫䉠『Əḍ姊㱡䛟旃┶栳˛怀䮮媽㕮⯴㕟⭟䔳⽘柦 ᷴ⯶Ə場䔆⇡䙫媽㕮⇭∌⇱䙢㖣ᷰỤ柩⯽㕟⭟㜆⇱˛ ⹛Ə䱚䈥㜔⒯Ⱓㇷ䂡ṭ⏙Ḡ䥶⤎⭟䙫㕟⭟㕀㍯˛ 䱚䈥㜔⒯Ⱓ㒬㖣怴㭞䏭媽˚徂⹥Ἴ⑳曀㛙⹥Ἴ䬰㖠杉䙫 㕟⭟>@˛⥠㛥✏娑┶壈㎷∗凑ⷘ⯴曀㛙⹥ἼⰋ⅝㛰凯嶊˛Ἴ 嫩曀㛙⹥ἼƢ曀㛙⹥Ἴ⑳Ḕ⭟ᷧ刓⭟∗䙫⹥Ἴḍᷴᷧ㨊˛ᷧ 刓Ὥ媑Ə勌/㘖䛛䷁俳3㘖滅Ə僤态怵3ḍ᷻⑳/⹚堳䙫䷁ㆰ婙 ⏑㛰ᷧ㢄˛Ἥ✏曀㛙⹥Ἴ䙫᷽䔳壈Ə僤态怵3ḍ᷻⑳/⹚堳䙫 ䷁Ə㕟憶㘖䄈昷䙫Ƅ怀Ẃ䏭媽偤嵞Ὥ⏖僤⽯㊤屈˚⏋】ƏἭ⭪ Ὸ⯴ᷴ⏳䮫䕮䙫䦸⭟䟻䩝惤⤎㛰⹒⊐˛凰ῲὲ⬷Ə㄂⛇㖖❍ 䙫䛟⯴媽䟻䩝Ⱈ怲䔏ṭ曀㛙⹥Ἴ˛ ⤎䜥⾪Ḕペ₶䙫㕟⭟⮝⏖僤惤㘖✏溸㝦ㇽ䴀ᷱ⥕䬭䖥㛟 䙫ạ˛⃿䮈䱚䈥㜔⒯Ⱓ✏㕟⭟ᷱ⎽⽾樼ạ䙫ㇷⰘƏ⥠⍢塏䤡 凑ⷘ㘖ᷧ⏴䷐ㅉ䙫〄俪⮝˛⥠㉱凑ⷘ䙫䟻䩝㖠⻶㮻▢䂡㣕㝾 䙫ⅹ暑Ə䕝὇✏㣕㝾忞巖Ə὇⾬柯∐䔏ⷙ㛰䙫䟌嬿Ὥ㦲怇ⷌ ⅞˚≜ὃ㖗㉧堺Ə䛛凚㛰ᷧ∢὇䩨䄝䙣䏥Ə凑ⷘⷙ䵺∗总ⱘ 柩Ə㉱ᷧ⇮惤䛲⽾ᷧ㷬ṳ㥁>@˛ ⹛Ə⥠墒㍯ṯ叙䈥匙䌵ƏỌ塏㏁⥠⯴㊤屈⹥Ἴ䙫岉 䍢Ə㊤屈⹥Ἴ⏖Ọㆰ䔏✏⅝ẽ柿⟆Ə⥩⊼⊂⭟˚姯䭾㩆䦸⭟⑳ ⭮⮀⭟>@˛ịạ恡ㆥ䙫㘖Ə䱚䈥㜔⒯Ⱓ凮䘳䖮㈗欌ṭ⹛Ə㛧 䴩㖣⹛㛯怄᷽ƏẒ⹛㭙>@˛ 㯒䄈䕸┶Ə䱚䈥㜔⒯Ⱓ㘖ᷧἴ⁸⇡䙫㕟⭟⮝Ə䂡⅝ẽạ 䕀ᷲṭᷴ⏖〄字䙫ㇷ㞃⑳ⷌ⅞ƏịạῸ⏖Ọ⻡⟡㖣⥠䙫ㇷⰘ ᷱƏ乣乳⯲㰩㖗䙣䏥˛晋㭋Ḳ⣽Ə䱚䈥㜔⒯Ⱓᷴ€㘖ᷧῲ岉 䍢剖⤁䙫⭟俬Ə俳᷻㘖ⷳ㜂㉼庒䦸䟻䙫⥚『䙫㦃㨊˛ᷧ栭㕟 ⭟Ḳ㘆暽䄝ⷙ怄ƏἭ⥠㈧䕀ᷲ䙫⽘柦⯮㛪敞⬿˛

What

comes to your mind when being asked “which animal is the smartest beside human beings”? Your answer might be chimpanzees, dogs or dolphins. But do not count ravens out of the picture yet. Studies have found that they have the brainpower strong enough to give those smar t mammals a run for their money [4,5]. For instance, ravens are able to use tools to manipulate their surroundings [3]; they can remember how to perform a complex series of actions [3] and even make sophisticated gestures to communicate [4].

But how can bi rds be as smar t as the said mammals, even though their brains are much smaller? One thing to note is that brain weight has nothing to d o w i t h co g n i t i ve s k i l l s . Moreover, despite using different p a r t s o f t h e

brain to think – apes use the neocortex while birds use the pallium – both classes of animals faced similar challenges during evolution, which boosted their brains’ cognitive performance [1].

As an example of how smart ravens can be, a recent study by researchers from institutes including the Lund University and the University of Vienna discovered their ravishing abilities to make judgments to cope with their complex social life [2]. These large and heavily built crows can somehow assess a deal as either “fair” or “unfair”. To test this hypothesis, Müller et al (2017) taught nine captive ravens to trade bread, a low-quality food, for cheese, a high-quality food.

First, a trainer presents a raven with a “fair” deal; they gave the bird a piece of bread from one end of its cage. If the bird brought the bread to

the other end of its cage, the trainer then exchanged it with a piece of cheese. On the next set of experiments, however, the raven was given an “unfair” deal. Instead of exchanging food items, a new trainer ate the cheese and took the piece of bread away. After two days, the experiment was conducted again with the “fair” trainer, the “unfair” trainer, and a new “neutral” trainer. The “neutral” trainer would return the bread when a bird decided to trade with her, allowing the bird to choose again with whom to exchange. Out of seven birds tested, six of them traded with the “fair” trainer, while only one chose the “unfair” trainer.

In one month, the experiment wa s repeated ag a i n i n the same manner. Out of all nine b i rd s te s te d, s eve n t ra d e d with the “fair” trainer, one with the “unfair” trainer, and the remaining one chose a new

References ⊁仁宅㑗濣

[1] Fernandez, C. 2016. Not bird-brained at all! Crows and ravens are ‘just as clever as apes’ when it comes to thinking logically and using tools. Mail Online (web), retrieved from: http://www.dailymail.

co.uk/sciencetech/article-3476525/Not-bird-brained-Crows-ravens-just-clever-apes-comes-thinking-logically-using-tools.html

[2] Gibbens, S. 2017. Ravens Hold Grudges Against Cheaters. National Geographic (web), retrieved from: http://news.

nationalgeographic.com/2017/06/ravens-memory-unfair-trade/

[3] Heinrich, B., Bugnyar, T. 2007. Just How Smart Are Ravens? Scientific American (web), retrieved from: https://www.theguardian.com/science/2007/apr/29/theobserversuknewspages.uknews1

“Bird Brain”?

Ravens Think Otherwise

More us

[4] Lazendorfer, J. 2016. 10 Fascinating Facts About Ravens. Mental Floss (web), retrieved from: http://mentalfloss.

com/article/53295/10-fascinating-facts-about-ravens

[5] Montanari, S. 2017. We Knew Ravens Are Smart, But Not This Smart. National Geographic (web), retrieved from: http://news.

nationalgeographic.com/2017/07/ravens-problem-solving-smart-birds/

[6] Müller, J.J.A., Massen, J. J. M., Bugnyar, T., Osvath, M. 2017. Ravens remember the nature of a single reciprocal interaction sequence over 2 days and even after a month. Animal Behaviour, 128:69-78.

[4] Lazendorfer, J. 2016. 10 Fascinating Facts About Ravens. Mental Floss (web), retrieved from: http://mentalfloss. com/article/53295/10-fascinating-facts-about-ravens

[5] Montanari, S. 2017. We Knew Ravens Are Smart, But Not This Smart. National Geographic(web), retrieved from: http://news. nationalgeographic.com/2017/07/ravens-problem-solving-smart-birds/

[6] Müller, J.J.A., Massen, J. J. M., Bugnyar, T., Osvath, M. 2017. Ravens remember the nature of a single reciprocal interaction sequence over 2 days and even after a month. Animal Behaviour, 128:69-78.

loss.

“neutral” trainer. However, when an “obse r ve r” bi rd was put in a different cage adjacent to where the experiment was conducted, it did not show as strong of a preference to the “fair” trainer as the “first-hand-experiencer” bird did.

This experiment showed that the ravens remembered who was the reliable “fair” trainer and who was not, which led to insights of how the birds’ complex social structure evolved [6]. Bear in mind that the bread-cheese trade in this controlled ex pe r iment does not occu r normally in the wild, but this study does lead to a further understanding on how smart ravens could be.

晋

ṭạ桅Ḳ⣽Ə䔁溣⊼䉐㛧偗 㗵Ƣ὇⏖僤㛪ペ嵞溸䌐䌐˚䊾ㇽ俬㵞 屁ƏἭṆ∌⾿ṭᷧ䏔㸈泰˛㛰䟻䩝䙣䏥Ə 㸈泰䛟䕝偗㗵>Ə@˛䉇Ὸㆩ⽾∐䔏ⷌ

By Rinaldi Gotama㘌Ⓡ⹵

־ЈऻอᐈȊ൧᝷ߞᇟށӹ

ݽ߰

⅞>@˚⁁⇡ᷧ怊ḙ䙫丨壮䙫⊼ὃ>@Ə 䔁凚僤Ọ壮曃䙫⊼ὃ㺄态>@˛ ὇⏖僤㛪⥤⤮Ə㸈泰䙫⤎免㮻溸䌐 䌐⑳䊾䬰䬰䙫⊼䉐䴗⯶⽾⤁Ə䉇Ὸ䙫偗 㔶䧲⺍⿵溣⏖僤䛟㮻⑉Ƣ⅝⯍Ə⊼䉐⤎ 免䙫憴憶⑳䉇Ὸ䙫婴䟌僤⊂ḍ䄈旃偖˛ 䦸⭟⮝䙣䏥Ə⃿䮈䌐䌐⑳泌桅〄俪㘩怲 䔏䙫⤎免惏ἴḍᷴ䛟⏳ƏἭ⅐䨕⊼䉐✏ 㼒敞䙫怙⋽怵䧲Ḕ惤杉⯴䜧䛟ἣ䙫㋸ ㈗Əᾪὦ䉇Ὸ⤎免✏婴䟌㖠杉䙫䙣ⰼ >@˛ Ὥ 凑 / X Q G  8 Q L Y H U V L W \ ⑳ 8QLYHUVLW\RI9LHQQD䙫䦸⭟⮝㗐∴ 䙣䏥Ə㸈泰㒨㛰ᷧ⮁䙫∋㖞僤⊂ƏỌ ㆰế䉇Ὸ壮曃䙫䤥ẋ䔆㴢 >@˛䦸⭟⮝ 0OOHU⑳ẽ䙫⛿晱䙫⯍樾䴷㞃 桖䤡Ə㸈泰⏖Ọ⇭徏ẋ㗺㘖␍˥⅓⹚˦˛ 䟻䩝ạⓈ䙣䏥ṭ㸈泰▃㭈劄⣒⤁ 㖣溜⋬˛✏⯍樾ḔƏẽῸℯ⏸㸈泰怙堳 ˥⅓⹚˦䙫ẋ㗺Ɲ䟻䩝Ⓢ⾅䱇⬷䙫ᷧ恱 䵍㸈泰ᷧ⠱溜⋬Ə⥩㞃㸈泰㉱溜⋬ₚ ∗䱇⬷䙫⏍ᷧ恱Əᷧἴ˥⅓⹚˦䙫䟻䩝 Ⓢ㛪䵍䉇劄⣒Ọὃẋ㏂˛㎌䜧㸈泰㛪䵺 㭞˥ᷴ⅓⹚˦䙫ẋ㗺Ɲ˥樀⬷˦䟻䩝Ⓢᷴ 㛪⑳㸈泰ẋ㏂棆䉐Ə俳㘖凑ⷘ㉱劄⣒⏪ ㍰Əḍ㋦嵗㸈泰䙫溜⋬˛⅐㗌⽳Ə䟻䩝 ạⓈ⑳㸈泰怙堳⏳㨊䙫⯍樾˛晋ṭḲ∴ 䙫˥⅓⹚˦䟻䩝Ⓢ⑳˥樀⬷˦䟻䩝ⓈƏ恫 ⤁ṭᷧἴ˥Ḕ䪲˦䟻䩝Ⓢ⎪凮⯍樾Ə‮ ⥩㸈泰恟㒮⑳˥Ḕ䪲˦䟻䩝Ⓢẋ㗺Ə⥠ 㛪㉱溜⋬恫䵍㸈泰Ə孺䉇憴㖗恟㒮ẋ㗺 ⯴屈˛⎪凮⯍樾䙫ᷪ暢㸈泰䕝ḔƏ⅔暢 㸈泰⑳˥⅓⹚˦䙫䟻䩝Ⓢ怙堳ẋ㗺Ə⏑ 㛰ᷧ暢㸈泰恟㒮ṭ˥樀⬷˦˛ ⤎䳫ᷧῲ㛯⽳Ə⏳㨊䙫⯍樾ⅴ㬈怙 堳˛⎪凮⯍樾䙫Ṅ暢㸈泰䕝ḔƏᷪ暢恟 㒮⑳˥⅓⹚˦䙫䟻䩝Ⓢẋ㗺Əᷧ暢恟㒮 ṭ˥樀⬷˦Ə⏍ᷧ暢∮恟㒮ṭ㖗䙫˥Ḕ 䪲˦䟻䩝Ⓢ˛㭋⣽Ə⯍樾怙堳㘩Ə䦸⭟⮝ ㉱ᷧ暢㸈泰㔥✏⏍ᷧῲ䱇⬷壈Ə孺䉇妧 ⯆⯍樾怵䧲˛ẽῸ䙣䏥Ə⑳㛥䵺⎪凮ẋ 㗺䙫㸈泰䛟㮻Əὃ䂡˥妧⯆俬˦䙫㸈泰 ⯴˥⅓⹚˦䟻䩝Ⓢ䙫‶⥤䛟⯴廪ἵ˛ ⯍樾桖䤡Ə怀Ẃ㸈泰姿⽾媗㘖˥⅓ ⹚˦䟻䩝ⓈƏ媗㘖˥樀⬷˦>@˛⃿䮈溜 ⋬⑳劄⣒䙫ẋ㗺✏⤎凑䄝Ḕḍᷴ⬿✏Ə 怀ῲ⯍樾䙫䢡⢅⊇ṭㇸῸ⯴㸈泰䙫婴 嬿˛

Humans

have been scrambling for resources since t h e h i s to r y of m a n b e g a n . Freshwater, food, and land have been our top concerns over the past decades; yet there is a shortage of one natural resource that we often miss out: sand. We may often associate sand with deserts, beaches and parks. Believe it or not, sand can also be viewed as a scarce natural resource as freshwater. Sand plays a much more vital role in

our society than you may expect. Its scarcity affects us all, whether you are a beach lover or not. Sand seems so abundant. How could the world be scrambling for it?

Sand and gravel are mostly co m p o s e d o f q u a r t z . W i t h a general formula of silicon dioxide (SiO2), quartz is consisted

of a co nt i n uous f ra m ewo r k of silicon-oxygen tetrahedral. Sand is primarily formed from weathering boulders. In the p roces s of weathe r i ng, the

weaker minerals in boulders are leached. Then the more impervious quartz is eventually ground down to various grain sizes. In time, the sand grains reach and accumulate in a low-lying area or form dune fields which later become deserts.

S a n d i s m o r e t h a n j u s t co n s t ituent s of beaches. It is involved in the making of everything from paint, bricks, s h i n g l e s , ce m e nt to w a te r filtration systems. Quartz in the sand is particularly valuable as it can make optical-quality glass and computer chips. In fact, sand is the most broadly used natural resource after water, acco rding to Pascal Peduzzi, director of science at the United Nations Environment Programme’s Division of Early Warning and Assessment. A 2014 report by the Programme also suggests that sand and

References ⊁仁宅㑗濣

[1] Renuka R. Even Desert City Dubai Imports Its Sand. This Is Why. BBC (2016). Retrieved from http://www.bbc.com/

capital/story/20160502-even-desert-city-dubai-imports-its-sand-this-is-why

[2] Ana S. How China Used More Cement in 3 Years than the U.S. Did in the Entire 20th _{Century. The Washington Post}

(2015). Retrieved from https://www. washingtonpost.com/news/wonk/ wp/2015/03/24/how-china-used-more- cement-in-3-years-than-the-u-s-did-in-the-entire-20th-century/?utm_ term=.420a8ad8b60f

[3] Joanna S. Why India Has a ‘Sand Mafia’. The Wall Street Journal (2013). Retrieved from https://blogs.wsj.com/

indiarealtime/2013/08/06/why-india-has-a-sand-mafia/

[4] P. Peduzzi, Environ. Dev. 11, 208 (2014).

gravel are the most extracted r e s o u r c e s i n t h e w o r l d , accounting for up to 85% of all materials mined around the world in one year [1]. Sand is so significant as an industrial and construction commodity that it is not an exaggeration to say that our modern society is built on sand.

Though sand penetrates almost all landscapes of our lives, most of it is not suitable for commercial purposes: desert sand, for example, is too smooth for construction uses and the purity of silica in the sand may not be up to par. Developing countries are among the biggest consumers of sand. China, for example, used more cement between 2011 and 2013 than the US did in the entire 20th century [2]. The global demand for the resource has prompted the rise of unregulated mining, which could lead to destruction of habitats like riverbeds and disruption of biodiversity [3].

Instead of crushing more rocks and mountains, industries are considering some more eco-friendly options, for instance, recycling glass and concrete. However, concrete in buildings could hardly be recycled unless the buildings are torn down, so that portion of sand is taken out of the recycling cycle almost permanently. Some companies are also considering alternatives, such as straw and wood for house construction, and mud for

reclamation.

T h e s c r a m b l e f o r s a n d a n d g r a v e l h a s c a u s e d unprecedented damage to our fragile environment, destroying wildlife and food webs, eroding h a b itat s a n d co m m u n it i es, and creating more pollution [4]. Global effort is needed to conser ve our lands, and our future.

凑

㕮㗵敲⦲Əạ桅ᾦᾄ杇⯲㉥ 岮㹷Ὥ䶔㋨䔆㴢˛Ἥ✏怵⎢㕟⌨⹛Ə㭊 䕝⤎䜥㒻⾪㛪␍㛰ᷧ⤐伡Ḷ㷈㰛˚棆䉐 ⑳✆✗㘩ƏạῸ⿤好ṭᷧ䨕䛲ἣ⹚⹚䄈 ⤮䙫岮㹷Ɲ㲀˛媑嵞㲀䟚ƏㇸῸㇽ⏑㛪 ペ嵞㲀㼇˚㲀䀿⑳⅓⛹䙫㲀㱇˛὇⏖僤 妡⽾㲀曊Ọ⑳㷈㰛䬰䎴岛岮㹷䛟㮻Əᷴ 怵Ə㲀岮㹷✏ㇸῸ䤥㛪㉕㻻䙫妹剙ㇽ㮻 ὇ペ₶Ḕ憴奨⽾⤁˛㲀岮㹷伡Ḷ䙫┶栳 ⑳ㇸῸざざ䛟旃˛㲀䟚⽞⽦暏嘼⏖奲Ə 䂡ầ溣㛪㛰䟔伡䙫ᷧ⤐⑉Ƣ 㲀⑳䤒䟚Ḣ奨䔘䟚勘䴫ㇷ˛䟚勘䙫 ⋽⭟⻶䂡ṳ㰎⋽䟤Ƌ6L2ƌƏ䔘䟤㰎⛂ 杉檻㈧㦲ㇷ˛㲀Ḣ奨䔘梏⋽䙫⷏䟚俳 ㇷ˛✏梏⋽怵䧲ḔƏ廪⼘䙫䤍䉐㛪楽ℯ 㴨⤘˛䄝⽳Ə廪⟬⛡䙫䟚勘墒䣏䡵ㇷ⏫ 䨕⤎⯶䙫㲀䱹˛暏吾㘩敺㴨怄Ə㲀䱹⟭ 䨴✏ἵ䪑✗⌧Ə⎯ㇽ㘖⽉ㇷ㲀᷿Ə⅝⽳ ㇷ䂡㲀㼇˛ 㲀ᷴ▕▕㘖㲀䀿憴奨䙫ᷧ惏⇭˛⾅ 㲠㻭˚䣁栔˚㰛㳌ƏỌ凚怵㿥䳢䵘䬰䬰Ə 怀Ẃ㝘奦䙫壤怇惤曧奨㲀˛㲀䟚Ḕ䙫䟚 勘Ⰻ⅝䎴岛Ə⛇䂡⭪⑳ℰ⭟䎢䑪⑳曢免 㙝䈮䙫䔆䔉㛰旃˛Ṳ⯍ᷱƏ㠠㓁偖⏯⛲ 䒗⡪奶≪余柷孍⑳娼἗惏敧䙫䦸⭟两 䛊ⷼ㖖⍈䈥澽ὐ㝃匙Ə✏⏫䨕⏫㨊䙫⤐ 䄝岮㹷ḔƏ㲀䙫ὦ䔏憶€㬈㖣㰛˛偖⏯ ⛲⹛䙫⠘␱ẍ㋮⇡Ə㲀⑳䤒䟚㘖 ⅏䏪敲㎈憶㛧⤎䙫岮㹷ƏἻ⅏䏪ᷧ⹛敲 ㎈憶檿总 >@˛㲀㘖壤怇 㥔⑳ⷌ㥔䙫⾬曧⒨ƏㇸῸ䙫䏥Ị䤥㛪⏖ 媑㘖⻡䮰㖣㲀岮㹷Ḳᷱ˛ 暽䄝㲀⬷⹥ḵ暏嘼⏖奲ƏἭ⭪Ὸ⤎ ⤁㕟惤ᷴ恐⏯䔏㖣┭㥔䔏忻˛㲀㼇䙫㲀 䱹⤑⹣Əᷴ恐⏯⻡䮰ὦ䔏Ə俳᷻惏⇭㲀 ⬷䙫䟚勘䳻⺍⏖僤总ᷴ∗奨㰩˛䙣ⰼḔ ⛲⮝㘖㲀岮㹷䙫㛧⤎㵯俾俬Ḳᷧ˛Ḕ⛲ ✏凚⹛㜆敺ὦ䔏䙫㰛㳌Ə㮻 併⛲᷽ᷱ䳧㘩ὦ䔏䙫恫奨⤁>@˛⅏䏪 ⯴㲀岮㹷䙫曧㰩㗌⢅Ə⯵凛㜑⎾䛊䮈䙫 ㎈㲀㴢⊼㗌㼟⢅⤁Əㇽ㛪䠛⣅㲚⹱䬰䙫 凑䄝䔆ㄲ䒗⡪Ə⽘柦䔆䉐⤁㨊『>@˛ 凮⅝䱰䡵㛛⤁䟚栔Ə䛟旃堳㥔㭊俪 ㅕᷧẂ㛛䒗ῄ䙫恟㒮Əὲ⥩⛅㔝䎢䑪⑳ 㷞⇄✆˛ᷴ怵Ə晋杅ạῸ㊭晋⻡䮰䉐Ə ␍∮⻡䮰䉐䙫㷞⇄✆曊Ọ墒⛅㔝˛㭋 ⣽Ə惏⇭⅓⏟㭊⯲㰩㛦Ị⒨Əὲ⥩ὦ䔏 䦥䧯⑳㜏㜷⻡怇㈦ⰲƏㇽ㘖䔏㳌㼦⡒ 㵞˛ 怵⺍㎈㲀⯴ㇸῸ䙫䒗⡪怇ㇷ∴㈧ 㜑㛰䙫䠛⣅Ə⍘⮚憵䔆⊼䉐⑳棆䉐䶙Ə 㑎㮧㣙ざ✗⑳䤥⌧Ə怇ㇷ㛛⤁䙫㱈㞺 >@˛⅏䏪曧⏯ὃῄ孞䒗⡪Əῄ孞ạ桅䙫 ⯮Ὥ˛

Conventional

wisdom has it that the onset of winter and cooler weather brings forth an inundation of flu cases. Runny noses, sore throats and incessant coughing are among the common symptoms for those unfortunate enough to fall ill to the common cold, most often caused by a virus known as the rhinovirus. With runny noses being more frequent in cold environments, the association between cold weather and the common cold was bound to happen. The truth behind whether this illness rears its head more prominently during wintertime, however, is very much up for debate.

Initial efforts to discover the cause of the cold began with Walter Kruse in January 1914. When one of his colleagues showed up to work with a cold, Kruse took samples of his nasal secretions and diluted them fifteen-fold with saline. He then passed the mixture through a fine ceramic Berkfeld filter to remove any bacteria (viruses are often much smaller in size than bacteria and would therefore pass through). Kruse gave samples to twelve of his colleagues to inhale and four of them developed colds after incubation for 1-3 days (talk about team spirit). The crude experiment proved that the cold was not caused by bacteria, but by a virus [1]. While this information seems archaic compared to what we know today, whether viruses really caused sickness went unanswered at the time. Further experimentation seemed necessary.

Chimpanzees were purported to catch colds from their zookeepers, making them ideal test subjects. Chimps that were kept in isolation from one another were given bacteria-free filtrates of nasal secretions from humans who had contracted the common cold. These chimps developed human-like symptoms of the cold. Test subjects that were given filtered nasal secretions from healthy humans did not, confirming the hypothesis that a virus was indeed responsible for colds and was, in fact, contagious [2]. It wasn’t until 1956 that the cold virus was isolated and cultivated. Two competing strains were discovered in the same year and appeared to possess slightly different characteristics. Both, however, induced mild respiratory symptoms that resembled a cold [3].

One of the f i rst studies to challenge the convention that low temperatu res increase susceptibility to a cold appeared in 1968. The experiment involved 44 American male prisoners. The newly discovered cold virus was dripped into the noses of 27 “volunteers” (the question of ethics for this experiment perhaps warrants an article on

its own). They were then subjected to temperature conditions of either 4 °C or 32°C during infection, incubation, peak of illness and recovery. The authors concluded “no significant differences” regarding the probability and severity of infection between those deliberately infected and the control group [4].

Yet even w ith this seeming ly convincing experimental evidence, the jury is still out. Cold temperatures constr ict blood vessels in the nasal canal to maintain body temperature. Vasoconstriction drives defensive

mucus in the nasal passage, which is designed to trap pathogens,

b u t w h i c h a l s o l o w e r s respirator y defenses [5]. This is because, should breathing take place through the mouth instead of the n o s e , t h e d e f e n s e s o f th e n a sa l m ucosa a re bypassed entirely. Low h u m i d i t y, a h a l l m a r k of w i nte r season, a l so expedites the travel of infected mucus droplets i n the a i r. The lowe r the humidity, the more rapidly water evaporates, creating a more streamlined projectile with a greater lingering period following a sneeze or a cough. In addition to these biological reasons for keeping the debate

open, one popular school of thought suggests that cold weather motivates people to congregate in close indoor quarters. This would have the effect of increasing proximity to the sick thus potentially facilitating contagions; recycled indoor ai r exacerbates this situation still further. The theory would also predict an increased prevalence of the common cold during colder weather.

Most scientists would agree that cold weather itself does not cause a cold, but that the cold is caused by a collection of rhinoviruses, each having its own virility in cold temperatures and the other conditions that accompany winter weather. Our habits in cold weather may also indirectly contribute to the spread of the virus. The best prevention is to cover your mouth and nose during sneezes and coughs, wash your hands thoroughly, and exercise regularly. In the meantime, perhaps it wouldn’t hurt to keep warm.

n body temperature. defensive e, which is ns, s ugh e e e y ngg ct ctililee eriod ough. ogical ebate

References⊁仁宅㑗

[1] Atzl, I., Helms, R. A short history of the common cold. Birkhäuser Advances in Infectious Diseases. Pp 1-21 (2009). Retrieved from http://

www.ncbi.nlm.nih.gov/pmc/articles/PMC1299336/

[2] Tyrrell, D. A. J., Fielder, M. Cold Wars: The Fight Against the Common Cold. The Oxford University Press. Pp 17 (1987).

[3] Gwaltney, J. M. Jr., Jordan, W. S. Jr., Rhinoviruses and Respiratory Disease. Bacteriological Reviews. Vol. 28. No. 4, p. 409-422 (1964). Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC441239/pdf/bactrev00143-0053.pdf

[4] Douglas, R. G. Jr., Lindgren, K. M., Couch, R. B. Exposure to Cold Environment and Rhinovirus Common Cold – Failure to Demonstrate Effect. The New England Journal of Medicine (1968). DOI: 10.1056/NEJM. Retrieved from http://www.nejm.org/doi/full/10.1056/

NEJM196810032791404

[5] Eccles, R. Acute cooling of the body surface and the common cold. PubMed Rhinology. Vol. 40 (3): 109 -14 (2002). Retrieved from http://

www.ncbi.nlm.nih.gov/pubmed/12357708

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A Case

By David Ren

ᶹ⟥ἇ

Energy

s u s t a i n a b i l i t y i s a k e y contemporary issue. However, clean, renewable energy options are plagued by low energy density and cost inefficiency, propelling the continuous search for sustainable alternatives. A breakthrough in nuclear fusion offers a new paradigm for the development of renewable energy. Much like in the cores of stars, the combination of hydrogen atoms (the most abundant element in the universe) to form helium yields an enormous quantity of energy. Although there are significant kinks to iron out (to say the least), the first steps in making nuclear fusion a viable method of power generation have undoubtedly been made around the world.

Nuclear fusion should not be confused with nuclear fission, which involves the splitting of large atoms into smaller ones. It is an established means of generating power in nuclear power plants. In contrast, pure nuclear fusion does not release radioactive by-products. This advantage eliminates the problems caused by nuclear waste and the challenges posed by proper disposal. The energy released during nuclear fission is also three to four times smaller than the energy released during nuclear fusion, which is the epicentre of its attractiveness in energy development.

Nuclear fusion essentially involves fusing two nuclei together (generally hydrogen nuclei) to form a larger nucleus. While this process seems conceptually simple, it requires overcoming the Coulomb repulsion force between the two nuclei so that the nuclear force is able to hold the nuclei together. Thus, equilibrium must be established between the repulsive Coulomb force and the attractive strong force to hold this new nucleus together. For nuclei smaller than nickel-62, the process of nuclear fusion releases energy known as the binding energy [1].

Nickel-62 has the greatest average nuclear binding energy per nucleon than any other atom, meaning it requires the most energy per nucleon to split apart [2]. Lighter atoms tend to fuse towards Nickel-62 because the nuclei involved lose energy with each fusion. Heavier elements absorb energy to fuse as the resultant nuclei possess a greater energy than that of the reactant nuclei.

T h e p ro b l e m w ith n ucl ea r f u s i o n i s th at sustainable fusion takes place at temperatures beyond 5 × 107 _{Kelvin (the temperature of the}

outermost layout of the sun is 5 × 105 _{Kelvin or more).}

The repulsive Coulomb force between protons forces reactors to bring nuclei within 10-15_{m together}

so that the nuclear force overpowers the repulsion. Even in the ideal trajectory, protons zoom around at 20,000,000ms-1_{. At sub-optimal temperatures,}

a small number of highly energetic particles may still be sufficient to participate in nuclear fusion. International Thermonuclear Experimental Reactor (ITER) is aiming for 1.5 × 108 _{Kelvin to ensure the}

plasma is not self-neutralising and to ensure that nuclei have sufficient energy to overcome Coulomb repulsion.

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㠟偁孱 怙堳Ƌ俳 ⬷㠟 峑 䳧 䙫㠠㜓┶ 吓敲

nuclear fusion

㛶优婈

By David Ren ᶹ⟥ἇ

It would be ideal if we could sustain nuclear fusion at room temperature. Unfortunately, claims of ‘cold fusion’ in the 1950s have been entirely debunked. The fundamental issue here is the challenge of plasma confinement. In other words, the ionised gas (plasma) of hydrogen and helium at temperatures above 5 × 107 _{Kelvin must be reliably}

contained.

Fortunately, ionised gases are charged particles and can be manipulated by magnetic as well as electric fields. A design that optimises magnetic fields for plasma confinement is the tokamak reactor [3], as used in the ITER experiment in France as well as the Experimental Advanced Superconducting Tokamak (EAST) experiment in China. If the reactor operates at 108 _{Kelvin, deuterium nuclei (2H) has}

an average velocity of 1,000,000ms-1_{. The plasma}

at these temperatures is extremely unstable due to severe plasma turbulence.

To provide adequately strong magnetic fields, superconducting cables are laced around the tokamak ring. Without superconducting cables, the magnetic field would be too energy inefficient to operate – but superconductors require cooling to around 4.2 K (or -269 °C), which is also the boiling point of liquid helium. To achieve temperatures

more than 5 × 107 _{Kelvin while requiring}

near-zero temperatures to run alongside plasma is a challenge, to say the least.

Nevertheless, the EAST team has managed to sustain a hydrogen plasma chamber at 5 × 107 _{Kelvin for over 102 seconds [4]. Germany’s}

Wendelstein 7-X reactor has also achieved an impressive 8 × 107_{Kelvin plasma for 15 seconds.}

For researchers dubious of tokamak-based fusion reactors, the National Ignition Facility (NIF) at the Lawrence Livermore Laboratory uses 192 lasers to combust deuterium-tritium fuel pellets to spark fusion [5]. Alternatively, inertial confinement fusion involves ignition of the outer layer of deuterium-tritium fuel so that the resulting explosion causes a chain reaction, burning the remainder of the fuel [6].

While a neat idea, nuclear fusion is a classic example of “easier said than done.” In comparison to sending men to the moon or climbing Mount Everest, nuclear fusion has proven to be the toughest challenge yet, but nations are realising the potential it offers. For now, nature’s very own fusion reactor remains unbeaten and is responsible for providing all energy on Earth.

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Do you enjoy reading this article about nuclear fusion? This article, as well as the previous

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὇▃㭈怀䮮㕮䫇▵Ƣ怀䮮㕮䫇⑳Ḳ∴旃㖣₞梏䙫㕮䫇惤㘖⎽凑ㇸῸ䶙䫀䙫⭟䔆惏吤㠣˛ ⥩㞃὇㛰凯嶊斘孧㛛⤁䦸⭟㕮䫇Ə䛲䛲ㇸῸ䙫䶙䫀␎Ƅ晋ṭ䦸⭟㕮䫇Ə὇Ṇ⏖Ọ✏䶙䫀䛲∗ Ọ⽧䙫ˣ䦸姧ˤ曢⬷䈯曃婳Ə⑳⎪⊇⭟䔆⾜㕮㮻峤˛

http://sciencefocus.ust.hk/zh-hk/

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[1] Dr. Rod Nave, Department of Physics and Astronomy. Nuclear Binding Energy (July 2010). Georgia State University. Retrieved from http://

hyperphysics.phy-astr.gsu.edu/hbase/nucene/nucbin.html#c1

[2] Fewell, M. P., The atomic nuclide with the highest mean binding energy (1995). American Journal of Physics. Volume 63, Issue 7, pp. 653-658. Retrieved from http://adsabs.harvard.edu/abs/1995AmJPh..63..653F

[3] Kruger, S. E., Schnack, D. D., Sovinec, C. R., Dynamics of the major disruption of a DIII-D plasma (2005). Physics of Plasmas. DOI: 10.1063/1.1873872. Retrieved from http://www.scidac.gov/FES/FES_FusionGrid/pubs/kruger-phys-plasma-2005.pdf

[4] Limer, E., Chinese Fusion Reactor Sustains 90 Million Degree Farenheit Plasma Blast for Over 100 Seconds (February 2016). Retrieved from

http://www.popularmechanics.com/technology/infrastructure/a19350/chinese-east-fusion-reaction-sustains-102-second-plasma-blast/

[5] Biello, D., High-Powered Lasers Deliver Fusion Energy Breakthrough (February 2014). Scientific American. Retrieved from http://www.

scientificamerican.com/article/high-powered-lasers-deliver-fusion-energy-breakthrough/

The Wireless World

You would not want to mess up the beginning of the day by

failing to locate the right charging cable for your smartphone.

Although it has only been a few years since smartphone

manufacturers embraced wireless charging, the technology is

not exactly new. It has been applied in bathroom electrical

appliances such as rechargeable toothbrushes and shavers since

the 1990s. As a matter of fact, its early concept has been around

for more than a century!

W i r e l e s s c h a r g i n g i s s o m et i m es ca l l e d i n d u ct i ve c h a r g i n g b e c a u s e i t w o r k s b y a p h e n o m e n o n c a l l e d e l e ct ro m a g n et i c i n d u ct i o n, which British scientist Michael Faraday discovered in the 19th

century. It is primarily based on the Faraday’s Law of Induction. S i m p l e e l e c t r o m a g n e t i c induction involves a magnet and a coil of wires. If you keep moving a magnet back and forth within a coil of wire, an electric current could be produced. The faster the magnet moves, the higher the voltage is. Once the magnet stops moving, however, no electricity is induced. In other words, a magnetic field does not induce electricity – a changing field does!

By Twinkle Poon㸖㔲

C o nve r s e l y, i f yo u a p p l y a current on a coil of wires, a magnetic field is generated. If the current applied is a direct current (DC), the magnetic field points in one direction. If it is an alternating current (AC), which constantly changes its direction, the field also points in alternating directions.

The modern wireless charging system involves a base station or a charging mat, which has an inbuilt coil of wire. When the base station is plugged, the alternating current from the main electricity supply runs through the coil, generating a magnetic field that is also constantly changing in direction. When you place your device onto the base station, the coil of wire inside the device is “reached” by the field and a current is induced.

U n l i k e w i r e d c h a r g i n g , inductive charging does not require the conducting material to be exposed, making it a safer option for bathroom appliances. Nevertheless, the technology currently does come with some downsides. The base station and the device being charged have to be in close proximity. While you can hold your smartphone and move around with the charger wire still plugged to the phone, wireless charging requires your device to stay on a specif ic position. In other words, charging on the go may not be feasible. As the technology improves, h oweve r, w i re l e s s c h a rg i n g may soon become a standard feature for smart gadgets, home electrical appliances and even electr ic cars. It could totally change our exper ience with devices.

夤⾱ᾍ濕䐴Ḟ⻣斾㽸方夯 方濕㜊᳈∹Ḇ㶽⋂䣬䵍䴜◦Ჾ尵䕂 方

䲘濕堿兯Ჾ䐨⅝⟩ㄋ侻ㅈ方夯⍊ 方䲘ノ⅝Ƽ怋⫋ƽ濕廗䣬浹䀧ᵉ濕奮

徻᳋Ⳋ㗙弅⃮Ʋ㿴今濕敦匕㿟䲘 方ㄾ圑䕂㔬⊈濕ハỏピ⫅᳋㗁⁋弅᳈

廗䣬䮝䮓䕂ᵉ⾃Ʋῖ䩟㿟䲘 方ㄾ圑䕂⅝侻◦序ⴲㄋょ䏦㑺㔸侻方夯

䨇䨇䕂方⨎䏠⍿濕Ḅ⩁‴⪤᳤᳋䩕㓭Ჾ䣬ⱂ㑮䕂ㄾ圑Ʋ㒧㑺ᴛ⇿ⴲᶡ濕

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婑ᵸ⿍⾱᳋⃮䕂㓭濕㿟䲘 方侊⹊䕂⚸㗪䢏⨶≝䋄㒧◦Ჾ䔼⟘ⴲℋ⫯

坩䔺䊼ᵄ濊

This article may be useful as supplementary reading for physics classes, based on the DSE syllabus. 㠠㓁䉐䏭䦸㕮ㅸ婍媙䧲䶘奨Ə㜓㕮ㇽ⏖ὃ䂡 㛰䔏䙫壃ℬ孧䉐

䄈䷁ℬ曢⎯墒䨘䂡ㄆㆰℬ曢Ə⛇⅝ 傳⽳怲䔏ṭ曢䢨ㄆㆰ⎆䏭˛怀⎆䏭䔘勘 ⛲䦸⭟⮝㲼㊰䬓✏⌨Ṅ᷽䳧䙣䏥Ə俳⑳ 怀䦸⭟⎆䏭䛟旃䙫⮁⽲ẍ墒䨘䂡˥㲼㊰ 䬓曢䢨ㄆㆰ⮁⽲˦˛䰈▕Ὥ媑Ə奨⁁∗ 曢䢨ㄆㆰƏ⏑奨孺䢨搜✏曢䷁⛯Ḕ∴⽳ 䧢⊼Ə曢㴨ᾦ㛪䔉䔆Əḍ㴨⊼㖣䷁⛯˛䢨 搜䧢⊼䙫怆⺍ワ⿒Ə曢⢺ᾦワ檿˛‮⥩ 䢨搜⁃㭉䧢⊼Ə䷁⛯ᾦᷴ㛪䔉䔆曢㴨˛ ㏂姧ḲƏᷧ䛛ᷴ孱䙫䢨⠛䄈㲼䔉䔆ㄆㆰ 曢㴨Ə奨䔉䔆ㄆㆰ曢㴨Ə䢨⠛⾬柯䶔㋨ 孱⋽˛ ‮⥩ㇸῸ孺曢㴨态怵曢䷁⛯Ə⑏⛴ ᾦ㛪⇡䏥䢨⠛Ə俳䢨⠛㛪⎾曢㴨㖠⏸⽘ 柦Ə⥩㞃ὦ䔏䛛㴨曢Ə䢨⠛㛪䶔㋨▕ᷧ 㖠⏸Ə⎴ḲƏ⥩㞃ὦ䔏ẋ㴨曢Ə⍚曢㴨䙫 㖠⏸ᷴ㖞ẋ㛦㛛㔠Ə䢨⠛ẍ㛪ᷴ㖞㔠孱 㖠⏸˛ 䏥✏孺ㇸῸ䛲ᷧ䛲䏥Ị䙫䄈䷁ℬ曢 䳢䵘˛䄈䷁ℬ曢⹼⺎ㇽℬ曢㝦ⅎ壈壄㛰 曢䷁⛯Ə䕝⹼⺎㎌ᷱ曢㹷Ə㎹⺎䙫ẋ㴨 曢㛪态怵曢䷁⛯Ə䔉䔆⇡ᷴ㖞㔠孱㖠⏸ 䙫䢨⠛˛㔖㏛䄈䷁ℬ曢㉧堺䙫曢♏ⅎ壈 ẍ㛪壄㛰曢䷁⛯Ə䕝⭪墒㔥✏⹼⺎ᷱƏ ᾦ㛪⎾⹼⺎䙫䢨⠛⽘柦Ə䔉䔆曢㴨˛ ⑳㛰䷁ℬ曢䛟㮻Ə䄈䷁ℬ曢䙫曢♏ ᷴ曧奨⣽朙⯵曢惏ỤƏ䔏㈝ᷴ⾬㒻⾪曢 ♏⛇㿡∗㰛俳䙣䔆㻶曢ヶ⣽Ə⛇㭋㵛⮋ 曢⬷䔉⒨⽧⽧㎈䔏䄈䷁ℬ曢㉧堺˛䏥ằ 䙫䄈䷁ℬ曢㉧堺䛲ἣ㖠ᾦ⭰⅏ƏἭẍ㛰 ⅝ᷴ嶚Ḳ嘼˛奨怲䔏䄈䷁ℬ曢Ə曢⬷䔉 ⒨曧奨㔥✏⹼⺎ㇽℬ曢㝦˛‮⥩䔏㈝ⷳ 㜂✏ℬ曢㜆敺ὦ䔏䔉⒨Əㇽ⸝⅝⇡敧䙫 婘Əℬ曢䷁㚒㘩ᾄ䄝㘖ῲ廪⥤䙫恟㒮˛ ᷴ怵Ə暏吾ℬ曢㉧堺「怆䙣ⰼƏ䄈䷁ℬ 曢䛟Ὲ⯮㛪ㇷ䂡㙡僤䔉⒨˚⮝䔏曢♏Ə 䔁凚㘖曢⊼㱤庱䙫⾬₀⊆僤ƏㇸῸ䙫曢 ⬷㙡僤䔆㴢Əㇽ⯮墒䄈䷁ℬ曢㉧堺⤎⤎ 㔠孱˛

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Pooping

might be a rather unsavory subject to discuss. Yet, study of feces could often provide us with valuable information about one's health. Many gastro-intestinal diseases, like irritable bowel syndrome and gastrointestinal infections, are manifest in abnormal size, shape, color or texture of excrement. They affect millions of people worldwide, and cost billions of dollars annually [1].

Fluid dynamicist Professor David Hu of Georgia Institute of Technology and his PhD student Patricia Yang joined hands with colorectal surgeon Daniel Chu, and the then undergraduates Candice Kaminski and Morgan LaMarca to dive into the science of pooping. The research group set out to look into the size, density, viscosity, smell and the duration of poop across different species, and

The Physics of Poop :

Why It Matters

built a mathematical model of the duration of defecation. The intrepid scientists literally took the matter into their hands – Kaminski and LaMarca filmed animals defecating and hand-picked feces from 34 mammalian species at Zoo Atlanta.

The “poop-analysis” yielded intriguing results. Through measur ing the densit y of the feces collected, the scientists found that the feces could be separated into two classes: “sinkers” and “floaters”. “Sinkers”, denser than water, are usually from carnivores like tigers and lions. “Floaters”, on the other hand, are usually from herbivores like elephants.

Despite their wide range of body sizes, the majority of mammals share a stunning consistency

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ᾦㇽ㘖ᷧῲ曊䙢⤎暬Ḳ⟩䙫婘栳ƏἭ怀ᷴỊ塏ㇸ Ὸㆰ婙⿤好⭪ⰘㇸῸ⁌⺞㈧㎷ᾂ䙫㛰䔏岮姱˛娘⤁兟傪䖥 䖬Ə⥩兟㗺㾧䶃⏯䖮⑳兟傪䁵䬰Ə✏㍹㲫䉐䙫䕗⸟⤎⯶˚⽉ 䊧˚栶剙⑳峑✗Ḕ惤㛰巈⏖⯲˛怀Ẃ䖥䖬㮶⹛ᷴ€⽘柦⅏䏪 㕟Ọ䙥吓姯䙫ạƏ㛛怇ㇷ㕟Ọ⃫姯䙫䵺㿆㏴⤘>@˛䔘㭋⏖ 奲Ə㍹ᾦ䙫䟻䩝䢡㛰⅝憴奨『˛ ▓㲢ẅ䏭ⷌ⭟晉䙫㴨檻⊂⭟㕀㍯'DYLG+X˚⅝⍁⣒䔆 3DWULFLD<DQJ凮䴷䛛兟⣽䦸憒䔆'DQLHO&KXƏỌ⎱䕝㘩䂡 ⭟䔆䙫&DQGLFH.DPLQVNL⑳0RUJDQ/D0DUFD⏯ὃƏ怙堳 ⤎ᾦ䛟旃䙫䟻䩝˛ẽῸ怙堳ṭᷧ䳢⇾䙫⯍樾Ə妧⯆ᷴ⏳⊼䉐 䳅ᾦ䙫⤎⯶˚⮭⺍˚溶⺍˚㰊⑚⑳㍹ᾦ㘩敺䙫敞䟔Əḍ⻡䪲ᷧ ῲ旃㖣㍹ᾦ㘩敺敞䟔䙫㕟⭟㨈❲˛怀Ẃ䦸⭟⮝䂡䟻䩝⏖嫩妑 ⊂妑䂡Ű .DPLQVNL⑳/D0DUFD✏昦䉠嘔⤎⊼䉐⛹㊴㔄 ⊼䉐㍹ᾦ䙫怵䧲Ə⎯妑㈲㎈暭ṭ䨕ⓡṚ桅⊼䉐䙫䳅ᾦ˛ 怀Ẃ旃㖣䳅ᾦ䙫⇭㝷䔉䔆ṭᷴ⯸㛰嶊䙫䴷媽˛忶怵憶⺍ 䳅ᾦ䙫⮭⺍Ə䦸⭟⮝䙣䏥⊼䉐䳅ᾦ⤎凛⏖⇭ㇷᷲ㱰䙫⑳㵕嵞 䙫⅐䨕˛⮭⺍㮻㰛檿䙫䳅ᾦ㛪ᷲ㱰Ə俳᷻态⸟Ὥ凑偰棆『⊼ 䉐Ə⥩俨嘵⑳䌬⬷˛⏍ᷧ㖠杉Ə㛪㵕嵞䙫䳅ᾦ态⸟Ὥ凑匰棆『 ⊼䉐Əὲ⥩⤎屈˛ 䟻䩝䙣䏥Ə⃿䮈㵰⎱䟻䩝䙫⊼䉐⤎⯶䛟ⷕ⽯恇Ə䉇Ὸ㍹ᾦ ㈧劘䙫㘩敺⍢⇡ḵヶ㖀✗ᷧ凛˛‮娔揿⽉㛙䷁⇭Ἧ䙫婘Əᷴ 媽㘖䢐⤎⥩屈Əㇽ㘖䴗⯶⥩屺Ə⯴⤎䳫ᷰ⇭Ḳṳ䙫ⓡṚ桅⊼ 䉐Ὥ媑Ə㍹ᾦ㈧曧㘩敺✮Ẳḵ凚䦹˛ By David Iu ⢘奞氞

References⊁仁宅㑗

[1] Mehta, F. Report: Economic Implications of Inflammatory Bowel Disease and Its Management (2016). Retrieved from http://www.ajmc.

com/journals/supplement/2016/importance_of_selecting_appropriate_therapy_inflammatory_bowel_disease_managed_care_ environment/importance_of_selecting_appropriate_therapy_inflammatory_bowel_disease_managed_care_environment_report_ economic_implications_ibd

[2] Rose, C., Parker, A., Jefferson, B., Cartmell, E. The Characterization of Feces and Urine: A Review of the Literature to Inform Advanced Treatment Technology. Critical Reviews in Environmental Science and Technology (2015). 45 (17): 1827–1879

[3] Hu, D., Yang, P. Physics of poo: Why it takes you and an elephant the same amount of time. The Conversation (2017). Retrieved from

https://theconversation.com/physics-of-poo-why-it-takes-you-and-an-elephant-the-same-amount-of-time-76696

when it comes to poop time, the study suggests. It takes about two-thirds of mammals – small cats and large elephants included – between 5 and 19 seconds to poop, assuming a bell curve distribution. Body mass seemed to positively correlate with defecation rate. An elephant defecates at 6 cm per second, three times as fast as the average human. The volume of feces varies hugely from animal to animal. The average elephant stool has a volume of 20 liters, several hundred times that of an average human defecates per day [2].

Defecation duration is relatively constant, even though the volume varies extensively. How can big animals defecate at such high speed? The answer lies in the properties of the mucus lining of the colorectal walls.

Instead of being squeezed like toothpaste out of a tube, feces move along the large intestine like “a sled sliding down a chute” by a layer of mucus. Since the mucus is more than 100 times less

viscous than feces, it serves as a lubricant and helps push the much more viscous feces out. This could explain why bigger mammals could defecate at high speed despite their longer feces, as they often have a thicker layer of mucus in their large intestine. On the other hand, a thinner mucus or abnormal changes in the mucus may lead to defecation difficulties and ailments.

You may wonder if the “poop-analysis” has any practical value or significance. Indeed, the defecation data could be applied in aspects such as engineering and medicine. For example, a new adult diaper that keeps feces away from direct skin contact was designed, so that astronauts could stay in their space suits for a longer duration. In medicine, the experimental results could shed light on alterations in mucus during bacterial infections like a C. difficile infection of the gastrointestinal tract [3].

See, the study of poop is no stinky science at all!

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From

shampoo, air refreshers to body spray and pe r fume, f rag rance is an indispensable part of modern daily life. Perfume has existed

for over 4000 years according to recorded history. Before synthetic compounds began to be discovered in the 19th _{centur y,}

fragrance ingredients were extracted from natural sources, from common plants l i ke flowe r s, he r bs, to weird, exotic animals like male deer secretion and beaver scent glands [1]. Nowadays, t h e m a i n c o m p o n e n t s o f p e r f u m e i n c l u d e a c o m p l i c a t e d m i x t u r e o f vo l a t i l e f r a g r a n c e compounds, alcohol and water.

Distilled water (H2O)

and ethyl alcohol (C2H6O)

a r e a m o n g t h e m o s t co m m o n l y used “ca r r i e r s”, which serve as solvents for the scent-bearing compounds. The f rag rance com pound s a re s ma l l and have a low molecular weight (usually smaller than 300 Daltons), so that they are light enough to float and disperse in the air [2]. When the molecules pass through the nose, receptors will send electrical signals to the brain, which then leads to a perception of the odour.

Some of you may have heard of the chemical term “aromatic compounds”. While aromatic compounds are often used in the making of fragrance, the word “aromatic” here has little to do with smell. Aromatic compounds are a large categor y of unsaturated organic compounds that contains at least one benzene ring (C6H6). A

compound is classified as aromatic only because of its chemical structure, but not its smell.

Not every aromatic compound gives a strong distinctive odour. Not every odorant chemical compound belongs to the aromatic family either. Ammonia (NH3), for instance, is inorganic and gives

a fishy smell. Ethyl butyrate (C6H12O2) is a natural ester t h a t s m e l l s l i k e pineapple. T h e o d o u r o f chemicals varies hugely f r o m c o m p o u n d t o compound. Some are pungent and unpleasant, while some are sweet or fruity. Naphthalene (C10H8),

for example, is the compound that gives moth balls their strong smell. Toluene (C7H8) is responsible for the distinct scent of

paint. Vanillin (C8H8O3) and anisole (C7H8O), as you

may guess from the names, give the pleasing smell of vanilla and anise.

A perfume is usually consisted of three parts: top notes, middle notes and base notes. Top notes

are considered as the first noticeable smell, made up of molecules that evaporate

most quickly. The middle notes

l a s t l o n g e r o n t h e s k i n, s e r v i n g a s the main and characteristic aroma of the fragrance. Finally, the base notes emerge as the middle notes dissipate [3].

Now that you have a better idea of the basic chemistr y behind fragrance, you may u n d e r s ta n d t h e r a t i o n a l e behind common advices about fragrance. People are often advised to apply fragrance to their wrists and behind their ears. These areas are warmer and the heat could enhance vaporization of molecules. Also, keeping the bottle in a cool, shaded place helps

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This article may be useful as supplementary reading for chemistry classes, based on the DSE syllabus. 㠠㓁⋽⭟䦸㕮ㅸ婍媙䧲䶘奨Ə 㜓㕮ㇽ⏖ὃ䂡㛰䔏䙫 壃ℬ孧䉐˛

Perfume:

the Chemistry

of Attraction

By Twinkle Poon㸖㔲

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References ⊁仁宅㑗濣

[1] Thorpe, JR (2015). The Strange History of Perfume, From Ancient Roman Foot Fragrance to Napoleon’s Cologne. Bustle. Retrieved from

https://www.bustle.com/articles/101182-the-strange-history-of-perfume-from-ancient-roman-foot-fragrance-to-napoleons-cologne

[2] Helmenstine, A. (2017). All About Odor Chemistry. ThoughtCo. Retrieved from https://www.thoughtco.com/

aroma-compounds-4142268

[3] Nasa, S. (2015). How Perfume Works. How Stuff Works. Retrieved from https://science.howstuffworks.com/

perfume.htm

Further Reading ⶴ᷶摯娾濣

Turin, L. (2006). The secret of scent : Adventures in perfume and the science of smell (1st U.S. ed.. ed.). New York: New York : Ecco.

Mattos, A. C. (2011). Scent as a medium for design: An experimental design inquiry

lengthen the lifespan of a fragrance as it avoids oxidation catalyzed by sunlight and heat.

Chemists have been working to synthetically replicate different kinds of smell, opening up countless possibilities of scent applications. Maybe someday you will be able to spray your room with a fragrance that mimics the smell of your favourite food, or a scent that reminds you of your treasured childhood memories. The making of fragrance is a creative craft combining art and science together.

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Coumarin, which has a sweet odour