水是宇宙中最多的化合物，宇宙元素數量最多的三種是氫氦氧，數量比大約是1200:100:1，其他重元素數量都不多，排行老四的碳數量約為氧的2/3弱。
有的書會寫這些元素的質量比，只要乘上各個元素的原子量1:4:16:12即可。
氫、氦主要來自大霹靂後的產物，其他重元素主要來自恆星演化、死亡後，由核心噴發出來的殘骸、遺物，數量才會遠少於宇宙早期的原住民。
氫、氧都是活性很高的元素，一接觸就火花四射，合成比較穩定的水，如果溫度、環境適合，水是宇宙數量最多的化合物一點也不奇怪。
有人說生命三元素是陽光、空氣、水，這三樣都和氫、氦、氧的親戚，而水不但數量龐大，也是最神奇的化合物。
水的循環是生態多樣化的保姆，水可以腐蝕、切割地表最頑強的物質，水可以載舟、也可以覆舟，水是生命的祝福，也是宇宙最強悍的英雄。
水的數量龐大，而且有能力翻雲覆雨、毀天滅地，但是太平盛世時就像溫柔的陽光輕撫，讓人誤以為可以對水為所欲為，就像獅子獵殺數量龐大的水牛群。一旦水牛被惹惱了，一旦水牛知道可以團結圍攻獅子，獅群很快就會滅絕。
水牛要團結、團結真有力。水要覺醒、要團結，要知道自己是偉大的一氧化二氫。
考試的目的只是想確認同學瞭解試題的內容與試題的物理，同學可以尋求任何協助回答問題，只要是自己寫下自己懂的即可。
助教會先檢查一下答案，老師再做詳閱，請務必自己解題，不要和其他同學解答重複、雷同，減少助教的困擾。
繳交報告後可以和同學討論，但是不要直接將自己的報告交給同學，也可以找以前修過課的同學討論、求教，但是不能要答案卷，或直接抄襲。
萬一同學抄襲你的報告，被學校發現可能會被認定作弊，萬一同學拒絕修改 或讓老師找不到人，甚至咬定他是原創、是你抄襲，（記住，抄襲和繳交時間順序無關）這樣會說不清楚受到連累，而且協助同學作弊也是作弊，提醒同學務必留意。
看完考卷，也請同學協助回答連結的問卷調查，謝謝。
The purpose of the exam is to make sure you understand the problems. It doesn't matter how you manage to understand the problems as long as you know the physics behind them.
The teaching assistant will check the answers first, and then I will grade them in detail. Please make sure to solve the problems by yourself and not duplicate or plagiarize the answers of other classmates to reduce the TA's workload.
After submitting the report, you can discuss it with your classmates, but do not share your report with them directly. You can also discuss or seek advice from classmates who have taken the course before, but you cannot ask for their answer sheets or directly copy their work.
If a classmate plagiarizes your report and the school discovers it, it may be considered cheating by the administration. If the classmate refuses to make changes as requested (or I cannot contact the classmate), or even worse, they insist that they are the original creator and that you plagiarized their answers (remember, plagiarism is not related to the submission time sequence), it will be difficult for you to explain and you may be implicated. Furthermore, assisting classmates in cheating is also considered cheating. Please be careful.
Please also check the survey form after going thru the exam problems.
https://www.worldnuclearreport.org/The-World-Nuclear-Industry-Status-Report-2022-HTML.html
Cosmology Student Survey
Thank you for taking the time to complete this survey. Your feedback will help us improve our class on cosmology.
Thank you for taking the time to complete this survey. Your feedback is valuable to us.
Thank you for taking the time to complete this survey. The following questions are designed to help us better understand your experience and opinions regarding the cosmology class. Your responses will be kept confidential and used to improve the quality of the course.
What is your current academic level? 你目前的學籍是 a) undergraduate b) graduate
What is your major or intended major? 你的系所專長是
a) cosmology or particle physics b) physics c) science or engineer d) others
How would you rate your prior knowledge of cosmology before taking this class? 你認為修課前自己對宇宙學的基礎知識為何？ a) None b) Beginner c) Intermediate d) Advanced
How would you rate the difficulty level of this course? 課程內容是否太困難？ a) Too easy b) Just right c) Somewhat difficult d) Very difficult
How would you rate the difficulty level of the first 6 problems of the take-home exam.? 期末考前六題對你而言是否太困難？ a) Too easy b) Just right c) Somewhat difficult d) Very difficult
How effective were the lectures in helping you understand the knowledge on cosmology? 課程進行方式對你瞭解宇宙學有幫助嗎？ a) Extremely effective b) Somewhat effective c) Neutral d) Not very effective e) Not at all effective
Did the course meet your expectations? 課程內容是否符合你修課的期待？ a) Yes, it exceeded my expectations b) Yes, it met my expectations c) No, it did not meet my expectations
How often did you engage with the course content outside of class time? 老師說宇宙學需要大量時間消化，你是否經常研讀宇宙學？ a) Every day b) Several times a week c) Once a week d) Less than once a week
Do you have any suggestions for improving the course? 對課程是否有任何建議？
Thank you for your participation in this survey. Your feedback is valuable to us.
Dear All,
We would like to hear your thoughts on your experience in our cosmology class. Please take a few minutes to complete this survey form. Your responses will help us improve the course for future students.
How would you rate the overall quality of the course? A. Excellent B. Good C. Fair D. Poor
How organized and well-structured was the course? A. Very organized and well-structured B. Moderately organized and well-structured C. Somewhat disorganized and poorly structured D. Very disorganized and poorly structured
How helpful were the course materials, such as the lecture note and video recordings? A. Extremely helpful B. Moderately helpful C. Somewhat unhelpful D. Not helpful at all
How effective was the instructor in conveying the material? A. Extremely effective B. Moderately effective C. Somewhat ineffective D. Completely ineffective
How often did you feel challenged in the course? A. Very often B. Moderately often C. Occasionally D. Rarely
How often did you feel lost or confused in the course? A. Very often B. Moderately often C. Occasionally D. Rarely
How well did the course meet your expectations? A. Exceeded my expectations B. Met my expectations C. Partially met my expectations D. Did not meet my expectations
What suggestions do you have for improving the course?
the lion sleeps tonight A-Wimoweh A-Wimoweh
a mishearing of the chorus of 'uyimbube' (meaning "he is a lion" in Zulu)
https://en.wikipedia.org/wiki/The_Lion_Sleeps_Tonight
Hakuna Matata!
Hakuna Matata
