About Mr Donnell Koh

Mr Donnell Koh was recently featured on Climate Change – A Wicked Problem, a documentary by Channel News Asia in March 2021.

Watch the video on YouTube! : )

Donnell graduated from NUS Chemical Engineering with 2nd Upper Honours. He used to work as a chemical engineer, but deep inside he always wanted to teach. After 3 years of working in the private sector, he enrolled into National Institute of Education (NIE) to get his Post Graduate Diploma in Education (PGDE) and fulfill his dream of becoming a chemistry teacher in Singapore!

About Mr Donnell Koh, The Founder

His first posting was Merdian JC. He was the pioneer teacher in MJC and he was very excited to be part of a new ‘start up’. It was a brand new school and the students who first came in had high O level scores. Teaching there gave him a clear picture of the problems faced by weaker students in the study of O level Chemistry tuition Singapore. He always had to think of ways to simplify the concepts to enable them to understand the subject with ease. His teaching methods also became very precise and clear so students knew exactly what to focus on and the thought processes involved in solving the questions. He did extremely well with his first batch of Meridian JC students. They came in with 17 to 20 points but eventually in those classes he taught, many scored As and Bs for A Level Chemistry Paper.

Later in Raffles JC, he faced a different set of challenges. Some gifted students who already completed the Chemistry syllabus on their own had to be challenged further to excite them in the subject. They read beyond the syllabus and always asked thought-provoking questions. These students provided much for classroom discussion. Donnell, with his wealth of knowledge and experience teaching Chemistry over the past 13 years. He has been able to understand the needs of a wide spectrum of students from extremely weak ones to those who are very highly motivated and do not settle for anything less than A.

With this wealth of experience, he is able to adapt his teaching style to help the weaker students to catch up. Yet excite the better students to think more critically.

Teachers make a huge difference to classroom teaching, not just what they teach, but also how they teach and connect with the students. Although Clarity in teaching is of utmost importance. A teacher needs to put himself/herself in the shoes of the students and see problems from their point of view. Only then, can students queries and doubts be accurately addressed. This comes from years of teaching experience.

John C. Maxwell once said “People don’t care how much you know until they know how much you care.” How true this is! Teachers are in the ‘business’ of educating and moulding the lives of students. Teachers need to connect with students and students need to feel comfortable approaching the teachers when in doubt.

Having said so, the chemistry tutors need to be passionate and enthusiastic about the subject they teach and get the students fired up too! To encourage students to think deeper, we need to constantly challenge them and excite them with the subject.

Donnell’s Raffles Junior College class of batch 2006, 27 out of 28 scored an ‘A’ for Chemistry! This is truly a remarkable achievement for him as well as the class. After starting Twig Learning Center, about 90% of my students have obtained A and Bs consistently.

To do well in A-Level H2 Chemistry, students need to have strong concepts and awareness of Chemistry in their daily lives. As many A-Level questions are very much application-based instead of just rote-learning. Having strong concepts and clear understanding are critical for doing well in H2 Chemistry.

His lessons focus on getting students to understand the basics and helping them to make connections among the different Chemistry topics. If they have a good grasp of these key basics. He can make connections, they will be able to solve many higher order application problems. A typical O level Chemistry tuition classroom will be on concept explanation followed by hands on practice. Students also learn through going through examples that he does with them. It’s because many students have a weak foundation that they end up struggling with Chemistry at A levels. If they can understand and solve Chemistry questions, naturally they will be motivated to do well in the subject!

Donnell’s method of teaching ensures that students understand the concepts in his classes and are able to do his carefully-selected questions. The role of the students is to be able to problem solve. How can this be achieved? Students have to do the extra questions that are given out and make homework and revision of his notes as part of their daily routine. They should REVISE THE COPYRIGHTED NOTES. It cover the essence of the concepts and many application questions tested in school exams are already in there. If they can do all the questions within the notes (without looking at the answers). They will have understood all the key concepts and be able to ace the A-Level Chemistry!

As an A-Level Chemistry tutor in Singapore, Donnell strives not only to help his students get good grades. But more importantly, inspire them to discover the amazing wonders of Chemistry. Take a leap of faith and join him. It could change your life!

Why Choose Twig?

Are you struggling with Chemistry? Chemistry is a challenging subject and it is not easy to master. It is integrated with mathematics, physics and biology and the content can be overwhelming. It has lot of abstract theories which are not easy to grasp.Over the years, the syllabus has changed drastically. You look at a question and you don’t know where to start. You keep reading your notes to find the answers and yet you are still lost.If you can relate to this, you have come to the right place.Our principal tutor for Chemistry, Mr Donnell Koh, was a former Raffles Institution (JC) and Meridian Junior College teacher with a wealth of experience teaching the A level syllabus and a superb track record of getting students to excel for the A-level Chemistry exam (90% As and Bs).

Twig Learning Center started off specialising in A-level Chemistry. Over the years, the centre has seen many students graduating at the top of their A-levels cohort. Because of the many requests, we have started O Level and IP Chemistry tuition on top of A Level H2 Chemistry tuition classes.Many Chemistry tutors have come to hear about Twig Learning Center and applied to work for us. The Chemistry tutors with us have been carefully selected from a vigorous process. Their lessons are video recorded and analysed hence from this process we only select the best. Not only are our Chemistry tutors highly experienced, more importantly they are able to enable students to understand Chemistry with ease and invoke an interest in the subject.


Twig Learning Center notes are so clear and concise that we believe they are probably better than those from many top schools. Many of our students told us they refer to our notes solely for studying and revision. Immense time, thought and effort have gone into crafting these notes, making sure all ground is covered. The content and layout have all been well thought out for easy learning and reading for our students. The copyrighted materials are crisp and concise, with many summaries given for easy recap. We use pictures, flowcharts, mind-maps and annotations in our notes to facilitate understanding. The truth is A-level chemistry questions today require higher order thinking skills. You will not see any repeat questions from notes, tutorials or practice papers during the exams. However, fundamental concepts do not change. In order for students to excel in Chemistry, they must be exposed a range of challenging questions that link theory and application.

At Twig Learning Centre, we understand that there are just way too many questions out there. Hence we have done all the work by selecting the ‘must do’ questions of varying difficulty for students to practise so that learning is focused and precise. All questions come with complete step-by-step work solutions so students can follow the thought process in tackling these challenging questions. Materials are reviewed regularly together with the top schools as we adapt to the changes in syllabus and questioning formats. This ensures we stay relevant to the A-Level Chemistry curriculum.

Nucleophilic substitution

Two interactive SMART boards are used during lessons. It is more efficient as annotations can be done directly on the diagrams. The tutor is drawing directly on the board instead of a laptop and learning becomes more personal and interactive. Videos are also used to show complicated organic chemistry mechanisms and class experiments are conducted to explain concepts. At the end of a long day at school, students who attend our lessons are still able to concentrate and actually enjoy the lessons presented due to the employment of effective teaching aids and tools. All lessons are also screen-recorded. So if you miss any lessons you can watch the video with the complete notes as if you are attending an actual class. Students who have attended the lessons too can watch the recording to review the lessons if necessary at no extra cost. All these are done to ensure complete learning takes place.

After every lesson, a video summary of each lesson is shared in a private Telegram channel so in 5 minutes, students know exactly what are the key concepts in each lesson. This will help them to consolidate their knowledge and makes studying Chemistry easier as they will know exactly what to focus on. Although students only spend 2 hours with us every week compared to 7 hours of chemistry lessons in school but yet, many have commented that they learn a lot more here than in school. Learning has been made so much easier and precise with our well-designed teaching methods!

Smart board

Let’s be frank. Chemistry is not an easy subject to master. The learning curve is steep. There is more content to learn in 2 years of JC than the entire triple science content at O level all put together. Here at Twig, we make the subject easy to manage as concepts delivery is ‘to-the-point’. Mr Donnell Koh has an exceptional ability in explaining difficult, abstract chemistry concepts in a way that students will come out of the class feeling totally enlightened. Students will learn important key words to explain concepts for application during examinations. These key words are in bold and highlighted clearly in his notes. During lessons he also highlights the common misconceptions that students make in the study of Chemistry. Memorising is kept at a minimum as his teaching focuses on understanding. If the student understands, there is really very little to memorise.

Sometimes, Mr Koh teaches beyond the syllabus, and that allows students to understand the subject more holistically. There is a need for students to see the link between theory and question. Lessons are interactive and all students are encouraged to participate in class. His lessons are never one-way. He is constantly throwing open-ended questions at students during lessons to test their understanding. Layout of the classroom is spacious and uncluttered, unlike some tuition centres. In fact, all chairs and tables are arranged in such a way that allows the teacher to walk around and monitor the work done by the students. Mini assignments are given to students after every topic and once completed, they are marked and returned to them. This is a form of feedback for students to check on their understanding and ensure that they are able to apply the concepts learnt.

Mr Donnell Koh is an approachable tutor for Chemistry as you can read from the many testimonials. In addition, many students do stay back to ask him questions and clarify their doubts. Donnell will answer queries of all his students no matter how busy he is. Students do look forward to his lessons every week even after a long day in school.

Mr Donnell Koh
Additional Consultation

Lessons are carried out in a group setting and being a passionate and committed teacher, Mr Koh understands that some students may still have a lot of queries after lessons. As such, he always avails himself for personal consultation should a student need further coaching. All they have to do is make a prior appointment and head down to the centre in the afternoon or before lesson to seek clarification. Otherwise, he can be reached easily via SMS or Whatsapp. Consultations are free of charge as at Twig, we are excited when we see students interested in learning Chemistry and motivated to excel in the subject!

Additional consultation

Additional practices (with model worked solution) are given for every topic for students to practice independently. Occasionally, Mr Koh will have extra weekly lessons to conduct a quiz, go through some questions to ensure that students have more hands-on practice after every topic, or just a mini lesson to summarise important key take aways for every topic.

Also a mini assignment is given for students to complete and hand up to the tutor for marking. This is an important form of assessment. For the teacher to know how much the students have learnt and for the students to realize how much they have understood.

Flexible Schedule

Twig Learning Center understands that JC life is very hectic and students are overwhelmed with school activities, be it sports, societies, or community involvements. We have a flexible schedule with multiple time slots for students to make up within the same week. Hence, if students cannot make it for their usual timeslot, they can always make up on another day.

Moreover, all lessons are screen-recorded. So if you miss any lessons you can watch the video with the complete notes as if you are attending an actual class!

Flexible schedule
Crash Course

There will be crash courses every school holiday in March, June, Sep and Dec. During these crash courses, the important chapters are revisited to help new students to catch up on previous chapters that they missed. This will allow new students to integrate into the existing classes so they can follow the pace of the ongoing classes.

Crash course
We produce RESULTS

Mr Donnell Koh coaches a few hundred students yearly and 90% of students taught by him have achieved either A or B grades in their A-levels. This goes to show that Mr Donnell Koh has been very successful in what he does.

Many students who were once lost in the maze of Chemistry, after attending Chemistry lessons at Twig, they start to be enlightened and see breakthroughs. Chemistry even became the favourite subject of many. Many have been so inspired by Mr Koh’s lessons, that they went on to further their interest by majoring in Chemistry in the Universities and are doing well now. Chemistry is also a pre-requisite for entry into NUS Medicine Faculty. Mr. Donnell Koh has over the years helped many students score an A after attending H2 Chemistry tuition and that allowed them to pursue their dream to study Medicine

We produce results
So What’s Next? ENROLL NOW!

This is an opportunity for you to make a difference in your life. We can change your perception, your Chemistry grades, and possibly your entire life. It is rare to find tuition centers specializing in just one subject. It is even more uncommon to find a tuition center that provides free consultation and such flexibility in class schedules. More importantly, the secret to do well is found in the copyrighted proprietary notes!

Take this leap of faith and see how we can help you achieve your dreams. Call us now for a life-changing experience in the study of Chemistry at the best Chemistry tuition centre!

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