I came across an amazing website today called Science Questions with Surprising Answers. The website is run by Dr Christopher S. Baird, who teaches at the Department of Physics at University of Massachusetts Lowell. The website answers fascinating (and sometimes bizarre) questions with a rare balance of accuracy and clarity.
I particularly like the Chemistry section, which answers the question, “Are two atoms of the same element identical?” His answer is as follows:
“No. Two atoms of the same chemical element are typically not identical. First of all, there is a range of possible states that the electrons of an atom can occupy. Two atoms of the same element can be different if their electrons are in different states. If one copper atom has an electron in an excited state and another copper atom has all of its electrons in the ground state, then the two atoms are different…”
The blog actually reminds me of the book, What If?, which is a more comical (and less relevant) companion to this blog.
Browse his website and introduce it your students this semester!
“Talent, you have naturally. Skill is only developed by hours and hours and hours of beating on your craft” – Will Smith
I read an interesting article in The Conversation this morning, in which, author Kevin Donnelly claimed that the recent success of Shanghai’s students in international examinations such as PISA and TIMSS was owed to the “chalk and talk” teaching method that’s so popular in Chinese schools.
I have a different view. I think that their success was owed to one main thing: study-hours. Typically, school students in China spend ridiculous amounts of time practising for those tests, which usually translates into excellent scores on examination day. Here’s why.
Ericsson’s 10,000-hour rule states that on average, people become world-class ‘prodigies’ at a particular skill (such as playing a sport, chess, or an instrument) after spending about 10,000 hours practising that particular skill. The 10,000-hour rule was made famous by Malcolm Gladwell in his excellent book Outliers, who illustrates the rule using Bill Gates, Bill Joy, the Beatles and famous chess players as examples, all of whom spent about 10,000 hours practising before they had a major breakthrough on the world stage.
The notion that greatness comes with tenacious practice seems obvious to most adults. However, it seems less obvious to most children.
High-achieving students spend more time on their homework assignments. When the teacher doesn’t set any homework, the high-achieving students re-read the textbook and/or re-write their notes, allowing them to clock up extra study-hours before their final examination. Students with more study-hours, in my experience, really do get higher grades.
We can estimate the number of study-hours a student gets per subject during Years 11 and 12. Five Chemistry lessons per week totals 300 hours. Doing 3 hours of homework every evening (averaging 45 mins per subject) equates to another 300 hours in two years. Students who study each subject for 50 minutes a day during the school holidays will clock up an extra 80 study-hours. Weekly tutoring could add another 160 hours, and last-minute revision lectures (e.g. such as those from TSFX) could add another 10 hours.
Students who ‘cram’ for three weeks right before the exam for 8 hours a day, 6 days a week earn an extra 36 hours per subject.
First, we can see that sustained, deliberate practice throughout Years 11 and 12 is clearly the best way to clock up extra study-hours, and thus maximise your examination score at the end of the year. Second, we notice a huge disparity in the amount of time that students might devote to their studies in Years 11 and 12. The disparity in study-hours is about as large as the range of test scores you might find in a class: 42% to 90%.
Kevin Donnelly’s article neglects the fact that most of the Shanghai students who were chosen to sit PISA and TIMSS sat through countless practice exams prior to taking the real ones. Their schools will have forced them to take the “maximum” preparation in the chart above. To paraphrase Will Smith, the Shanghai students’ examination successes can be explained mostly by a “sickening work ethic”, and the countless hours of tenacious practice they clocked up before doing the exams.
I use the Will Smith video above (and some real-life examples) to demonstrate that even the most talented people can’t afford to be lazy. I tell students that there are no shortcuts to learning anything difficult, and that learning anything (including VCE Chemistry!) takes a large amount of time and effort – even for those students who are naturally ‘talented’.
Now, follow these steps to transfer your notes to an A4 pad. This key learning exercise is suitable for Years 10-12 and undergraduate level.
Part A: Stationery Shopping!
Get three colours of pens ready: black, blue and one other colour Always write in black or blue. Use the other colour to draw boxes, underline important words or make things stand out.
Use a large, sturdy, lined A4 pad. Do not use notebooks smaller than A4, and do not use notebooks with cartoons or other distractions pre-printed on the pages.
Part B: Making notes
If the teacher gives you notes for their PowerPoint lecture, don’t use them. Make your own notes instead. You learn by making notes!
Always write the date, title and subject in the same places on the page. It’s a simple rule but many students (especially in middle school) still don’t do this!
Add references. Always write the textbook page number in your notebook. If the teacher doesn’t tell you, just ask.
Organise your notes by writing subtitles. Use the same subtitles that your teacher uses (on the whiteboard or on their slides).
Use at least two colours. Colours guide the eye around the page. Use them logically: one colour for headings, another for questions, and another for definitions, etc. Only use legible colours such as black, blue and one other colour. Write mostly in black or blue.
Write neatly in easy-to-read, lowercase letters. Make your notes really easy for people to read.
Draw diagrams large and clear. Diagrams need a title, a caption, and everything needs to be labelled. Never draw a diagram without any words to explain what it means.
Write notes using “examination language”. The definitions and explanations in your notebook should be acceptable to use as answers in an end-of-year examination. The glossary in your textbook is the best source for definitions of scientific words. Make sure you can explain the concepts learned in both colloquial language and in exam-specific language.
Don’t try to save paper. Instead, your goal should be to use up your notebook. Whitespace is crucial to making the notes easy to re-read so don’t cram your text onto the page: leave some white spaces where necessary (e.g. between paragraphs and in the margin).
Part C: Reading and sharing your notes
Re-read your notes regularly Add to your notes using new knowledge you’ve learned from the textbook (and from class). This is why it’s important to keep your notes tidy and organised!
Add comments from examiners’ reports.
For example, “always write the ‘+’ symbol near the nitrogen atom on an amino acid in an acidic environment” would be a great comment to add (with a diagram) to the biomolecules section of your Chemistry notebook. This comment is paraphrased from a VCAA Examiners’ Report.
Share your notes proudly with students who miss lessons. Email them or share them online.
Re-make them into larger versions and put them onto your wall.
This not only looks impressive but also reminds you to stay focussed as examinations draw closer.
There are dozens of great note-taking tutorials on YouTube. Here’s one you can refer to for Science classes. Remember that the specifics of note-taking vary from person to person but keeping your notes complete, neat and organised should be one of your most important learning goals as a student.
Any questions? Are you a student with note-taking tips? Leave a comment below!
I love this speech. Neil deGrasse Tyson was interviewed by a TIME journalist for their 10 questions page, and was asked by one reader: “What is the most astounding fact that you can share with us about the universe?” Neil deGrasse Tyson’s response was as lucid and as awe-inspiring as always. He answered the question in a relatively modest three minutes, starting with:
“The most astounding fact… is the knowledge that the atoms that comprise life on Earth—the atoms that make up the human body—are traceable to the crucibles that cooked light elements into heavy elements in their core…”
Tyson is a world-famous astrophysicist and currently serves as director of the Hayden Planetarium in New York. He’s very popular on social media and recently hosted the hit TV series Cosmos, which had the biggest launch day in TV history (and featured a 30-second introduction speech by Barack Obama).
I love Neil deGrasse Tyson’s videos because they inspire people to pursue Science. I show one or two Tyson videos to as many of my students as I can, usually at the beginning of the year. Happy New Year.
Here are some of my other favourite Tyson videos on YouTube:
All classes contain students of mixed ability levels. However, performance in an end-of-year examination is more dependent on how hard a student is willing to work than on any measure of innate ability. Student learning correlates much more with “grit” than with talent. In other words, the more hours you study, the higher your grades will be.
In this article, I’m giving you my observations from a teacher’s perspective of what students in the top 20% (in terms of grades) tend to do.
1. They don’t play games on their iPad
Students with low scores tend to resort to picking up their iPads at every spare moment. iPad addiction is a typical sign that a student doesn’t spend any of their free moments reading or thinking. Successful students don’t usually have games on their iPad. If they do have games, they’ll be the more intellectually-stimulating ones such as Scrabble or quiz apps: you certainly won’t find an A-grade student frantically thumbing their iPad screen to Flappy Bird or Crossy Road between lessons.
2. They read the textbook at home, highlighting and annotating as they go
When I ask a class of students to open their textbooks to a certain page, four things happen:
The most successful students open their books to those pages, which are already highlighted and annotated with key vocabulary circled and translated/explained in the margins (see picture above);
The mid-range students open their textbooks, which look brand new;
The least successful students do nothing because they weren’t listening;
The remainder (if any) didn’t bring their book to school.
Reading the textbook before class does two things. First, it helps you to understand the lesson much better. It’s much more effective to read the textbook at home then ask questions in class than to learn the textbook in class then ask those questions at home. Second, a textbook that’s highlighted and annotated looks very impressive. Your teacher and classmates will be impressed.
3. They write neatly and colour-code their notes
Successful students use large, A4 notebooks. They write the date, title, and subheadings in the same places with the same colour pen. They don’t cram too much writing on one page, and they organise their notes heavily using subheadings.
An interesting studyfound that students who reviewed their own notes outperformed students who reviewed notes given to them by their lecturer.
4. They have a designated homework diary (or an app)
Successful students always remember to do their homework. They record their homework tasks in their diaries with due dates. Reminders for iOS does this job excellently.
5. They do all their homework on time
Even if the teacher forgets to ask to see students’ homework, the most successful students will actively hand it to their teacher because they’re proud of the work they’ve done.
Even if there’s no homework set, they’ll still spend time reading the textbook (or another relevant book) or watching YouTube videos to supplement their understand of what’s been taught. The most successful students are self-motivated.
6. They pay most attention to their teacher during the lesson
From experience, students who chat to each other too much tend to get low grades at the end of the year. They miss crucial instructions, homework, questions and information being delivered by the teacher. While it’s important to be sociable, the most successful students always pay more attention to their teacher than to their classmates.
“Students who reviewed their own notes outperformed students who reviewed notes given to them by their lecturer.”
7. They ask questions after class and email their teachers at evenings/weekends with questions regarding the homework
Most days, I receive Chemistry-related emails from students. However, these emails are usually sent by the same 30% or so of the students I teach. The students with the habit of asking more questions—both inside and outside the classroom—tend to fare better in the end-of-year examination.
8. They understand that we learn primarily through reading, and that the classroom is just a place to discuss what they’ve read and put it into practice
Successful students learn more outside the classroom than in. They read the relevant textbook section before class; they come to class with questions about what they’ve read. They re-read the textbook section after the lesson as well. They know that the more times they read the textbook, the more they’ll learn and the better their scores will be in the end-of-year examination. They know that their textbook (not their teacher) is their primary learning resource, and that their success depends more on how many hours they put into studying than on how ‘good’ their teacher is.
9. They know when to say, “Sir, I don’t get this!”
This is one of the most valuable skills on this list: admitting that we don’t know what we’re about to learn is the first step we take when we learn something new. Successful students have the confidence to admit to things they don’t understand and are thus more receptive when their teachers explain them. In other words, it’s a dangerous habit to pretend that you actually understand something—this habit usually has disastrous consequences before the end of the year. In a classroom, always admit when you don’t understand something.
“admitting that we don’t know what we’re about to learn is the first step we take when we learn something new”
What do you think?
Are you a student who agrees/disagrees with these 9 observations? Are you a teacher with more observations to add to the list? Write them in the comments section below.
Alkanes contain strong carbon-carbon single bonds and strong carbon-hydrogen bonds. There are no partial charges on alkane molecules that might initiate reactions. The effect is that alkanes only undergo very few reactions.
(1) Combustion of alkanes
Alkanes can undergo combustion, producing CO2(g) and H2O(g)
When asked to create a combustion equation for a particular fuel, do the following steps:
Alkanes can also undergo substitution, in which one of the hydrogen atoms is replaced with a halogen (e.g. F, Cl, Br, or I).
General formula: alkane + X2 → chloroalkane
Example: CH3CH3(g) + Cl2(g) + UV light → CH3CH2Cl(g) + HCl(g) (note that HCl is a gas!)
10.2 Reactions of alkenes
(1) Addition of alkenes
Alkenes can under addition reactions with halogens, hydrogen gas or water.
The first reaction happens at room temperature. If you have a gaseous alkene like ethene, you can bubble it through either pure liquid bromine or a solution of bromine in an organic solvent like tetrachloromethane. The reddish-brown bromine is decolourised as it reacts with the alkene.
(2) Addition polymerisation of alkenes
Chemguide is an excellent revision resource that goes a little further than VCE. Read the relevant Chemguide pages below.
When hydrochloric acid is added to propene, two products can be produced: 1-chloropropane and 2-chloropropane. Only the 1-chloropropane can be made into a carboxylic acid. We must therefore separate the 1-chloropropane from the 2-chloropropane by fractional distillation.
When reacting alkenes with 3 or more carbons (such as propene) with hydrochloric acid, we must write “HCl and fractional distillation” on the arrow.
Ever wondered why ‘formic acid’ is so-called? Or montanic acid? Or melissic acid? This handy A3 poster shows you the Latin/Greek/Persian origins of each of the carboxylic acids’ common names from ‘formic acid’ (no. 1) to ‘hexatriacontylic acid’ (no. 36). Each acid comes with a cute graphical description of where its name comes from.
There are some interesting origin stories behind each of these names. Formic acid, for example, is found in insect stings (hence the name). Palmitic acid is found in palm trees (hence the name), and myristic acid is found in nutmeg.
Three of the carboxylic acids are named after goats: caproic acid, caprylic acid and capric acid. Together, these three molecules comprise 15% of the fatty acids found in goats’ milk, and many reports also suggest that they smell ‘goat-like’!
Many of the odd-numbered higher carboxylic acids are rarer in nature and thus didn’t earn a common name until recently. Undecylic acid, for example, which has eleven carbon atoms in its backbone, is named simply after the Greek word for ‘eleven’.
The VCAA Chemistry Data Booklet contains answers to many questions you’ll be asked in the end-of-year examination. Unfortunately for students, however, the information it contains is neither explicit nor complete. Students need to know how to use the data booklet if they are to make the most of it.
Many formulae and definitions still need to be learned. For example, the data booklet doesn’t give you calorimetry formulae, and hydrogen bonds aren’t shown on DNA nucleotides. Trends are missing from the periodic table, and the electrochemical series comes with no annotations whatsoever! All this extra information needs to be memorised for VCE Chemistry.
The first project of the collaboration used a 4K UltraHD camera to capture beautiful chemical reactions in specially-designed glass containers that eliminate the problems of refraction and reflection caused by rounded beakers and test tubes. I also love how the researchers play with time, slowing down and speeding up the videos at just the right moments. The video footage is then annotated and matched perfectly with background music to give a truly mesmerising result. Here are three of my favourites:
Yan Liang, like the visionary data-visualisation gurus David McCandless and Hans Rosling, is passionate about bringing hidden data to the public domain in a form that’s really easy to digest. When I asked him what inspired him to make these videos, he said:
“To me, science is beautiful and full of wonders. However, the beauty of science is often hidden inside research laboratories and buried in scientific literature. By creating engaging visuals and make them available to the general public, I believe more people would appreciate the beauty and wonders of science, and hopeful get interested in science.”
“The goal is to bring the beauty of chemistry to the general public. To many people, Chemistry might usually be associated with pollution, poison, explosions, etc. We want to show them the other side of chemistry, which is much less well-known. We also want to get more kids and students interested in chemistry and inspire them to learn more chemical knowledge.”
Since Yan Liang, Edison Zheng, Jiyuan Liu, Xiangang Tao and Wei Huang launched Beautiful Chemistry on September 30th, 2014, they have received over 110,000 unique visitors and over 2 million page views. The project has been a huge success, and has already inspired young people worldwide to pursue Chemistry.
“People love our videos of chemical reactions. Some people commented if they saw these videos when they were in high schools, they might work harder and learn more chemistry. A 15-year old student from Germany and others told us our videos inspired them to shoot their own videos of chemical reactions. Artists like these videos and many request our footage to make music videos.”
Significant figures tell you how accurately a number is known. This invariably depends on the precision of your instruments.
To illustrate this, use a pencil and a ruler to draw a square with sides of 8.109435 cm in length. Now, calculate the area of the square that you’ve drawn.
A ruler can only measure length to within ±0.1 cm. Our square therefore has sides 8.1 cm in length (not 8.109435 cm) because our measurements are limited by the accuracy of the ruler. The area of our square is therefore 8.1×8.1=66 cm², not 65.762936019225 cm², because there was no way to measure all of those decimal places precisely using a ruler.
Accurately-known digits are known as significant digits. All other digits are described as not significant. We must always round our final answer (not the intermediate steps) to the correct number of significant digits by following the six rules below.
1. Numbers without a decimal point
First non-zero digit is significant
Last non-zero digit is significant
All digits in-between are significant
45 is to 2 significant figures (s.f.)
1,240 (3 s.f.)
68,686,000 (5 s.f.)
2. Numbers with a decimal point
First non-zero digit is significant
All digits afterwards are significant
1.2 (2 s.f.)
6.810 (4 s.f.)
900,001 (6 s.f.)
3. Scientific notation
Scientific notation is a way of writing numbers in the form:
a × 10b where 1 ≤ a < 10.
Count the number of significant figures in a to find the number of significant figures in the number (a × 10b).
5.56 × 103 is to 3 significant figures
2.012 × 10-4 is to 4 significant figures
Some unit conversions are exact and are said to have an unlimited number of significant figures.
1 minute = 60.0000000000… seconds (infinite s.f.)
1 metre = 100.0000000000… metres (infinite s.f.)
Temperatures usually have 3 (sometimes 4) significant figures when converted into Kelvin!
10°C = 283 K (3 significant figures)
100°C = 373 K (3 significant figures)
4000°C = 4273 K (4 significant figures)
5. Addition and subtraction
Rule: Always round your final answer (not any intermediate answers!) to the smallest number of decimal places.
441 + 65.42 = 506 (use zero decimal places)
200.1 – 144.2456 = 55.9 (use 1 decimal place)
6. Multiplication and division
Rule: Always round your answer so it has the same number of significant figures as the input value with the smallest number of significant figures.
481.56 × 14.5 = 6980 (use only 3 s.f.)
7800 ÷ 41.1 = 190 (use only 2 s.f.)
Remember to round your ANSWER (not the intermediate steps) to the correct number of significant figures.
Questions? Comments? Still confused? Leave a message in the comments below. I’ve tried to make sig figs as simple as I can in this post.
The priority at this late stage is that you enter the examination hall well-rested, well-fed and with an appropriate level of stress.
1. Sleep early every night
Go to bed before 10pm (or 9pm with an exam the next day)
Wake up naturally. If you’re waking up too late, go to sleep at 7pm.
Avoid backlit screens for one hour prior to sleeping. Backlit screens emit light in the 484-nanometre range, which excites melanopsin in the retinal ganglion cell photoreceptor. This disrupts your circadian rhythm and keeps you awake!
2. Eat healthily
Eat regular meals at regular times.
Eat plenty of fruit. (Five per day.)
Drink plenty of water.
3. Get some lighter exercise
Avoid exhausting sports around exam time (e.g. rugby).
Do more walking, jogging, and lighter sports at exam time (e.g. badminton).
Drink plenty of water(!) Aim to drink 3 litres per day.
Research has shown that you perform difficult tasks (such as a Chemistry exam) much better under moderately relaxed conditions. The famous Yerkes-Dodson curve illustrates this beautifully.