Author Archives: LEM

Married Half My Life Day

Romantic Maths.
Numbers are important! Today marks the special day in my life where I have now been married to my beautiful wife for as long as I had been unmarried. From tomorrow, I will have had more experience in life as a married man as I had had as a single man.
The calculation is pretty easy. To calculate your own “Married Half My Life” Day just follow the instructions in the video below.
It’s good being married. Studies have shown that married people are healthier and happier and that they live longer than single people. I don’t know if it’s true or not or whether, if it is in fact true, that it’s a chicken and egg situation; maybe people who are chronically unhappy and unhealthy find it harder to find a partner. We always have to be careful when we’re interpreting data.
Generalizations are fine, but they say nothing about individual cases. In my case though, it’s fantastic being married to Georgina, my wife and fellow video producer.

The Most Important Law that Students Should Be Taught

Good morning, everyone.
Before we begin the lesson, let me tell you about what I call the First Law of Economics.
This is it:
If you want someone to give you something, you have to give them something in return of a perceived equal value.
This Law applies to individuals, to businesses, and to entire countries.
So, if you go to the shop and you want to buy a T-shirt, they will give you a T-shirt, but they expect you to give them something in return: in this case, money. We can call the First Law of Economics the Law of Mutually Beneficial Exchange.
When, in the future, you get a job, what’s really happening is that you are going to give your time and your skills to the person you are working for and that person, in return, will pay you. Many of you will work for a boss, and so the exchange of skills (and time) for payment will be made through the business you work for. Some of you may start a business though, in which case you might be dealing directly with customers. When, for example, your tap is broken, you might call a plumber and the plumber comes and fixes it. In exchange for the plumber’s time and skill, you give the plumber money.
Basically business and individuals provide what are called “goods” (physical things like a chair or a light globe) and “services”. A service is something like the work that an accountant does when he or she prepares your tax return for you. Mechanics offer goods (like motor oil or spark plugs for your engine) and services (the actual work they do to fix or service your car). These goods and services are often referred to as “parts and labour”.
So, if in the future you want to work, it’s not really a matter of just saying you want to find a job (although there’s nothing wrong with that expression). It’s really a matter of mutually beneficial exchange. You will provide your skills or products or time or services to someone else and that someone else will give you payment in return.
Now, a lot of you may never have thought about it this way. Up until now, nearly everything you have has been provided for you. Your parents provide food and clothing and stuff and they don’t really ask for much in return. Love of course complicates things. (As a parent myself, the “payment” I receive from my own kids is the gratitude they express to me and, let’s face it, when they do well, I feel good! As I said, love complicates things.) In the real world of work, however, no-one is just going to give you stuff that you want if you don’t provide something in return that they want.
So, why are you at school? It’s because you need to learn the skills that you need to offer future bosses and future customers—for which you will receive your income.
If any of you have little brothers and sisters in primary school, you will know that there is no way they would be able to do most jobs. Most of them would struggle even to make, say, a coffee at a local café, or to stack shelves at the supermarket, both jobs that don’t require a huge amount of training and which don’t pay that well. However, most of you in this class could easily do these jobs because you’re a whole lot smarter than you were in primary school, and you’re bigger and stronger.
But this leads us to an important point. If the only skills you have are also possessed by millions of other people, then why would someone pay you top dollar when it’s easy for a business to find someone else to do the same work for a lower wage. We now get into the Second Law of Economics: Supply and Demand. Put simply, if it’s easy to find someone to do a particular job because it’s a low-skill job, then the payment will be low as well.
The people who are paid the most are the people who provide skills or services or products that few other people can provide. Lots of people can stack shelves at a supermarket, and though it’s a really important job and an honourable job, it’s a low-paying job.
So what skills do you have to offer now and what skills will you have to offer in the future? I want to encourage you all to work hard, to learn as much as you can at school, and to become as good as you can at reading, writing, and mathematics. In the world of work, no-one really owes you anything. To earn an income in the future, you will have to offer something in return. So make sure you gain the skills you need! And of course you’re all going to need the skills that I’ll be teaching you!!
Anyway, let’s begin the lesson.

Note to Teachers:

I often refer back to the First Law of Economics because of its pervasiveness. It doesn’t just apply to individuals but also to whole countries. For example, Shedding Light on Atoms Episode 3: The Discovery of Atoms describes how elements are extracted from mineral ores (for example, iron from iron ore which contains a high concentration of iron oxide). I often pause the video and talk about how Australia receives income from other countries by selling the iron ore and the steel that we produce to other countries.
I might say something like…
A large part of Australia’s wealth is generated from the fact that Australia as a country has things (in this case iron ore) that other countries want and which they are prepared to pay for. The international monetary system is pretty complicated but, at a really simple level, Australia gives iron ore to China and China gives Australia things that it produces (such as electronic equipment). It’s the First Law of Economics at work.
A country can only import things if it exports things as well.
And an individual person can only acquire something if that individual gives something in return. It’s the First Law of Economics: if you want someone to give you something, you have to give them something in return. And what do you have to give? Maybe not much at this stage because you’re young. But you’ll grow and continue to learn and by the time you finish your education you’ll have much much more to give than you do now!

Always do this before you try to answer a question on a worksheet or a test.

I would have thought it was obvious but it wasn’t obvious to (at least) three Year 11 Physics students in a class of about 20.

I had just finished teaching them the Law of Refraction using LEM’s Shedding Light on Refraction program. The bonus feature on this program explains how to calculate the angle that light will refract when it passes from one transparent medium to another. I then gave them the The Law of Refraction Worksheet. The worksheet has a list of formulas and other data. Here is a screen shot of part of the worksheet.

Question 3 asks:
A ray of light travels from air to glycerol at an incident angle of 38° and is refracted at an angle of 24.6°. What is the refractive index of glycerol?

Two students over the span of about two minutes asked the same question which was basically, “Sir, can you help me with this? I don’t know the refractive index of glycerol.”

Neither of them had read the question!!

Just as I was telling the second student that it’s the refractive index of glycerol that they needed to find, I heard another student (a third student) ask the same question to one of his mates.

I’ve been using this worksheet for years now and this had never happened before, but I thought this was a golden opportunity for an important teaching moment and I immediately stopped the whole class.
“Three students have just asked about question 3. They got confused because they didn’t know the refractive index of glycerol. This might sound a little crazy, but before you try to answer a question, you should always READ THE QUESTION first!!!”

A colleague of mine served as a Year 12 examiner for the Year 12 Chemistry exam for many years. A few years ago he told me that students routinely didn’t read the question in full before writing down their answers.
A common mistake was to answer only part of the question when the question was clearly in two parts. Another common mistake was to focus on a particular word in the first sentence of a question and then assume that the question was related to the definition of that word.

So, in summary,
STEP1: Read the Question
STEP 2: Answer the Question.

Never attempt to do it the other way around.

A Much Easier Way

What a teaching round! I recently had to supervise a pre-service teacher (what we used to call a student teacher). This was the last of three rounds that he did with me this year.
Unfortunately, I wasn’t able to let him teach the recommended number of lessons on his previous rounds because of the fact that I only work part time as a teacher. This time, however, I suggested that he teach both of my junior classes: a Year 9 class studying Heat and a Year 10 class studying Chemistry.
This would have been a huge workload because he also had to take a Maths class with his other supervisor.
To make his life easier, I suggested that he use the Shedding Light on Heat series to teach the Heat unit and the Shedding Light on Atoms series to teach the Chem unit.
So, on Day 1, he used Shedding Light on Heat Episode 2: Changes of State and its accompanying worksheet to teach the class why things change state. The explanation side of the teaching was taken care of by the video with animations, actual footage, and explanations. The students then used their memories and the online text book on the Changes of State page to answer the questions.
It was so easy!
I’ve seen plenty of pre-service teachers struggle to explain things verbally while using white-board markers and hand-drawn diagrams. Unfortunately, I’m also guilty of giving students less-than-satisfactory explanations that take too long. 🙁 A short sharp video, though, can take care of the explanations, which frees up a lot of time so that students can get on with actual learning activities.
The pre-service teacher also started teaching my Year 10 class about electron shells using Shedding Light on Atoms Episode 6: Electron Shells. Once again it was so much easier than legacy approaches.
By the end of his round he had taught the Year 10 class about electron shells, covalent bonding, and ionic bonding. During lessons, he would move around the room helping students who needed additional support.
He didn’t use just the Shedding Light programs, though. Interspersed throughout his round he organised a whole lot of pracs and a few mini-assignments. He also regularly asked students to read out their answers to the class, something I always do when I’m teaching to encourage better literacy. See The First Thing I Tell A New Class.
The reason LEM started making the Shedding Light videos was on full display during the teaching round. A good video makes it easy for any teacher, regardless of expertise, to communicate science concepts easily and effectively to their class, especially when the video is accompanied by learning activities and pracs.
The work the students did during the teaching round was of a very high standard. The pre-service teacher regularly collected it and then gave feedback.
Overall, he ended up teaching about twice as many periods as he needed to since the Shedding Light programs helped him in quite a few of them.
So, whether you are a beginner or an old hand experienced, try using a Shedding Light program to teach your class. They are available to schools that have ClickView, Learn360, Films on Demand, and SAFARI Montage, or you can order directly from the LEM website.
I wish the pre-service teacher, and you, dear reader, every success.

The First Thing I Tell A New Class.

Hi everyone. My name is Mr Liacos and I’m going to be your Science teacher this year. I’m hoping that you’ll enjoy Science. We’re going to do pracs, theory work, assignments, and other things, and by the end of the year you’ll know a lot more than you do now!
Now even though I’m your Science teacher, I also consider myself to be one of your English teachers. Probably the most important thing you learn at school is reading and writing, and even though you can all read and write, the more practise you get, the better you get.
So, I like Science and I like learning about Science (I became a Science teacher after all!), and I’m hoping you like Science too, but even if you don’t, I want to use the time in class to keep developing the two most important skills that anyone learns in school: reading and writing. You will use your English skills for the rest of your lives in every aspect of your lives.
So, whenever you’re answering questions, or writing down the observations you made in a prac, or completing an assignment, I don’t want you to concentrate just on the Science, but also on the English. I want you to try to write everything in your best English.
I don’t just want a correct answer, I want a well-written correct answer!
What I’m going to do is regularly ask you to read out what you’ve written to the rest of the class and I want to comment not just on whether your work is correct but also on the English. This way you get to practise your English more AND you’ll be able to teach others about the work we’re doing. You’re not just going to learn stuff from me, but you’re going to learn stuff from each other. This class is a learning community, and we are all going to contribute to everyone’s knowledge.
Finally, let me say this. Quite often, kids used to say to me, “sir, I get it, why do I have to write it down?” The science is often the easy part. It’s the English, the good English, the well-expressed English that is the difficult part. But it’s the most important part and the part that cuts across every subject and it’s the part that will help you more than any other part. So do your best. I’m looking forward to a good year.
So let’s begin…

Note to Teachers:
After, say, a prac, I usually get 4 or 5 kids to read out their answers to Question 1. I will then give feedback (mixed with praise where appropriate). I then get 4 or 5 kids to read out their answers to Question 2, and so on. This takes a bit of time, but it’s worth it.
I’ve been teaching like this for quite a few years now and it has been received very positively by my students. They get to show off their work to the rest of the kids, they get to hear “best-practice” answers from other kids which lifts everyone’s standards, and kids who may not have understood something first time get to hear the answers from their peers. Everyone wins. And that’s how classes should be!
After watching a Shedding Light program, I do the same thing with the worksheet answers. Students are asked to read out their answers. This reinforces the fact that what they write has to be understood by an audience, they practice their English, and they all learn from each other. And they’ve all got a much higher chance of learning a concept if they’ve heard it 4 or 5 times!
I am totally convinced that by emphasising literacy, but surrounding literacy within the context of Science, my students learn both better!
Epilogue: Even though I start by emphasizing literacy, it usually isn’t long before I start stressing the importance of numeracy. If you browse the Shedding Light worksheets, there are a lot of questions that require numeracy. I also make a big deal about numeracy, but I start with literacy.
So, try it out!

Statistically speaking, people are highly likely to misinterpret statistics!

Statistics are not easy to understand. They speak broadly of a whole population but say nothing about individual cases. I was watching a show on TV recently that reported that a study has found that in 70% of households women do more of the domestic duties (cleaning, cooking, ironing etc.) than men. A male commentator then rubbished the study, saying that he did nearly all of the housework, so it was obviously wrong!
But 70% means 70%, not 100%. If the study surveyed 1000 households and found that in 700 of them, women do more of the work, then that equates to 70%. In 300 households, men do more of the work (or do the same amount of work). Finding an exception to a majority doesn’t change the underlying statistics.
Statistics say nothing about individual cases, only about whole populations. So assuming that a set of statistics accurately reflects what’s going on in society (which is an assumption that you should always be careful of making), individual cases will vary.
However, politics (including societal politics and work-place politics) is not necessarily about accurate statistics. Politics is about winning people over, so people will often argue about what a set of statistics tells us about our society and what we should do. The interpretation of the statistics is often far more important than the statistics themselves.
So in commenting on the above statistics, some might say that “woman do more housework than men, so things could be better in terms of equality between the sexes”, or more emphatically, “woman are burdened with far more of the housework in society. This is unacceptable…” However, others might say that “the reason that woman do more household work is that they are more likely to be home due to children-related reasons which is completely their choice…”
General statistics are important, but the biggest arguments in society involve why something is the way it is and statistics don’t necessarily have the answers. So, always be careful about not just the statistics themselves but how they are interpreted!

Still Useful Four Decades Later

For a long time, teachers taught knowledge that they had acquired to students who had not yet acquired it.
With the internet, we are no longer necessarily taught by teachers who are in a classroom with us, but we can easily search for, read up on, and learn stuff from people anywhere on the planet.
This is my first blog post that I’m writing just to test out the software. No-one has directly taught me how to do it, but I am indebted to the many talented people who have written fantastic articles on the internet describing how to set up blogs and websites.
Having said that though, I couldn’t have done anything without the ability to read, to write, and to do mathematics, and these things I learned from my teachers.
So, if I learned how to set up a website (and to make Science videos) without actually attending a class for these things, what role will there be for teachers in the future (beyond teaching the basics)? With the amount of information on the internet, do we need teachers anymore? Well, text books have been around at least since 1980 when I started high school (and I’m told even earlier, but who cares, right?), but my teachers were still an essential part of my education.
The way kids (and all of us) learn stuff has changed a lot (and it will continue to change a lot). The use of videos, for example, has exploded over the past 10 years because it is now so much easier to show them from a computer. A lot of teachers are using the Shedding Light videos to take care of the actual instructional side of things.
However, students still need great teachers to guide them, to encourage them, to set high standards, to help them to set goals, to give feedback, and to teach them the skills that they do not yet know that they will need in the future.
Interestingly, when my teachers taught me to read, to write, and to do maths, I did not realize just how useful those skills would be even decades later. A lot of what we learn is like that.
So, teachers are invaluable!