What makes a good teacher?

(This post by Dr Daniel Milton Oman first appeared here on Domain of Singapore Tutoring Experts on 1 January 2013.)

By Daniel Milton Oman, Ph.D.

Some believe that when you walk into a classroom, the role of the teacher is to open up the top of your head, take a magic golden bucket of knowledge, pour the knowledge into your brain, seal the top of your head back up, and send you on your way. In this model, the conversation between teacher and student is one way. The teacher does all of the talking, the student listens diligently to everything being said and tries their best to instil within them the knowledge from the teacher, paying particular attention to absorbing the exam secrets that will allow them to score the highest possible grade on the coming assessment test.

But is this the best role of a teacher in the classroom? Certainly not.

My first year of secondary school, I had a great Biology teacher. He was mainly focussed on getting us to think like a scientist. He would walk around the classroom of about 15 students and have a class discussion with us. He would ask us questions that would really make us think. And he would not just give out the answers quickly. I remember him pacing around as we thought. He was patient. But he wanted us to go through the process of making sense out of things.

Here is a typical exchange that would happen in that biology class:

Teacher: Why is grass green?

Student 1: Because chlorophyll is green.

Teacher: Well, yes, so then why is chlorophyll green?

Student 2: It’s like a reflector of green.

Teacher: What do you mean it’s like a reflector of green, don’t tell me what it is like, tell me what it is.

Student 2: (smiling) OK, it is a reflector of green.

Teacher: Then what happens to the rest of the colours?

Student 3: They get absorbed.

Teacher: OK, the rest of the light is absorbed, and what happens to the light that is absorbed.

Student 4: It causes photosynthesis.

Teacher: All right, so Johnny let me ask you, does green light cause photosynthesis?

Johnny: Yes.

Teacher: Hmmm, the green is reflected right?

Johnny: Yes.

Teacher: So if green is reflected and not absorbed is it causing photosynthesis?

Johnny: Oh sorry, seems like it is not.

Teacher: So what might be an example of a colour that causes photosynthesis?

Johnny: Red?

Teacher: Yes, correct. Makes sense right? Red is absorbed, so it could be involved in photosynthesis. And it so happens that red, orange, and also blue light contribute to photosynthesis in different stages of the process.


Let me make a few points about our example class discussion.

Speaking properly and accurately:

In the 1980’s in Boston it was a habit of teenagers to say, “My Dad’s car is like bright red”, or “my history test was like really hard”. But in Biology class we learned that scientists don’t speak in a sloppy manner. We didn’t say what something was like, we said clearly and precisely what it was. In my career as an electrical engineer, I mostly dealt with people who spoke clearly and precisely. I think you learn that in the military also. If you want to say something, say it right. Helping and guiding students to express themselves properly is one important role of a teacher. This goes for verbal as well as written expression.

Making sure the class understands the concepts:

Notice the follow up question to Johnny by the teacher. The teacher was probing to see if he really understood. This is very important. The teacher may see a lot of heads nodding as if they understand, but you need to check. And the odds are if one student didn’t understand something, others are in the same boat.

Creating an environment where it is OK for the student to say something incorrect:

When Johnny gives the wrong answer, he is not condemned. And he must feel free to answer. The classroom is the place where it is OK for a student to make mistakes. As long as you are trying and putting in your best effort it is OK. The point is that you learn from your mistakes. If you never make any mistakes as a student, you are not learning as much as you could be. Any good teacher understands this.

Not giving the answers to every question right away:

Of course there are a certain amount of facts, formulas and basic concepts that need to be given to students. But for the application of these concepts, when you ask a question and the answer is not immediately obvious, that is when they have to think. That’s when they try to start making sense out of things. And helping them learn how to analyse problems is one of the basic principles of education. When you give out an answer quickly to the student, that’s when their thinking stops.


Which is more important, that we teach a student what to think or how to think? All good teachers know the answer to this, especially anyone who has experience outside of academics. And experience outside of academics is crucial to the development of a good teacher. The best teachers I can remember usually had experience either in research or in the corporate world. They knew what it really took to be successful. They knew the key was that you learn how to think, how to solve problems, and how to be creative.

Perhaps at this point some readers may think there is the following choice: 1. That I can learn how to think or 2. That I can score high on tests by rote memorization and drilling. This is a false choice. A good teacher guides you to both learn and do well on tests. You can learn how to answer questions by rote learning, or you can learn how to answer questions by having a good understanding of the subject; by really learning what you are supposed to be learning.

There are times when the teacher does have to be pragmatic. There are times when the teacher does have to say, “these are the kinds of problems that will be on your test and here is step by step how you solve the problems”. That is part of the learning process also. It is valuable and practical. But a good teacher is teaching the students to reach the goal of good grades through a proper process, which includes real understanding of concepts.

I had a funny interaction with a student in class last year. I asked the class, “What is osmosis? Can anyone explain it?” One very eager student raised his hand and when called on, closed his eyes tightly and recanted, “Osmosis is the movement of water from a region of high concentration to low concentration through a partially permeable membrane”.

I said “Wow, that sounds just like the textbook, OK – open your eyes now” The student then opened his eyes (I’m serious; this is exactly the way it happened). Then I said “In your answer you used the word “permeable”, can you tell me, what does the word permeable mean?”

The student then busted out laughing. I asked “What is funny?” and he said “I have no idea what any of that means, but my previous tuition teacher told me to memorize that answer for tests.” It was great that this kid was laughing because he knew how ridiculous that was. So we had a 20 minute class discussion about osmosis and we went over the concept thoroughly. We talked about two situations where the concept was applied, and we reached a good conceptual understanding as a class. But I have had this situation unfold in a similar way dozens of times and I hear more often that a tuition teacher is doing this to the kids rather than the school teacher.

Here’s the problem with the rote learning approach: Every year I have a JC1 physics class and it is guaranteed that some students come to me in shock during April. They failed their test! How could they be failing because they previously scored an A or B for their O-Levels! Yet now they can’t follow anything taught in JC class. Why? They forgot everything from O-Level. Why? They never really learned it, they just crammed for the test, got a test coach to help them stuff all the information into short term memory and a year later – poof! – all that information was gone! They never developed good problem solving skills. They never learned how to think about physics. And now they have to spend a huge amount of time redoing the process all over again at an even harder level. What a waste of time! No wonder the kids get stressed out!

Making it Interesting:

The teacher does have one more important task. That is making the subject interesting and connecting what the student is learning to the real world. I show short videos in class and also do experiments with the students so they can get a hands on feel for things. Again, if the teacher has real world experience, then doing this is natural. If the student can become interested and self-motivated, then their potential is great indeed. And they stand a much better chance of remembering things if they can relate to them.

The role of the teacher:

A good teacher does need to guide a student to good test results. This is crucial, no doubt. Tests are how students are measured, so a good teacher must be very practical. But how does the student achieve the good results? Is it because that magic bucket of knowledge has been poured into their brain? Actually, this is the hard way to learn, particularly for science subjects.

There is an easier way to get those good test results. It is by learning how to think and by developing good problem solving skills. These skills will stay with the student from lower Secondary, to Upper Secondary, to JC, to University, and all the way to their career. Therefore, the teacher is helping the student develop within themselves the skills that will allow them to excel in school and also in life. So the role of the teacher is to turn on that light bulb that lies within each student, so they can shine.

About The Author

Dr. Daniel Milton Oman is a Singapore PR who has lived here for 7 years. He has taught private tuition classes for science and physics since 2010 and has taught students from over 40 schools in Singapore, becoming very familiar with the local school syllabi. Daniel comes from the USA, where he taught physics at two Universities in Florida. He has published research papers on CO2 lasers and solar energy while pursuing his Master’s Degree and Ph.D. He also worked in the semiconductor industry, starting with AT&T Bell Laboratories. Daniel was a distinguished member of technical staff and worked on the manufacturing technology of the computer chips that went into the Ipod, cell phones, computer disk drives, and satellite radio. Daniel was also an engineering manager for 4 years in Singapore at a joint venture between Singapore company Chartered Semiconductor and US company LSI logic. He has co-authored 4 study guide books with publishers McGraw-Hill and Barrons. His combination of research and corporate experience along with his academic experience allow him to conduct his classes is a manner that relates science to the real world.

Visit his website at



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