Teaching science is beautifully challenging - we science teachers must draw upon real-world experiences, our perceptions of the world, our students’ perspectives of the world and a whole host of prior learning in our subject, as well as that in maths, geography, languages, D&T, the list goes on.

The culmination of all this provides a complex and informed understanding of the world, but achieving this level of complex understanding does not happen by chance - instead, it is achieved through a carefully sequenced series of learning, tonnes of practice and expert teaching. 

This is particularly true when examining the knowledge and skill required to perform titrations calculations. 

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An integral part of key stage 4 chemistry, this can be highly complex to pick apart for many students. However, with careful structure, appropriate testing and expert modelling, students are able to develop deep understanding of this concept and secure knowledge retention.

Teaching titrations for GCSE science

1. Mapping prerequisite knowledge

In order to plan succinctly for teaching titrations, it is imperative that you consider the prerequisite knowledge. How can we expect children to calculate the unknown concentration of a substance if they can’t manipulate calculations, do simple multiplications or divisions, or understand the concept of balancing equations?

Throughout your teaching and learning sequence, factor in sufficient time to teach, check and reteach each ingredient in teaching titrations.

In order to achieve success in understanding the concept of situations, students must already understand and be able to:

1.      Determine states of matter and their symbols.

2.      Confidently write balanced symbol equations.

3.      Recall the products of a neutralisation reaction.

4.      Have a deep understanding of the concept of moles.

5.      Convert between orders of magnitude (eg, cm3 to dm3).

6.      Manipulate equations.

All of this, alongside multiplying, dividing and, above all else, being able to read the question in an exam!

Therefore, ensuring that each of these discrete knowledge components are taught in sequence across your KS3 curriculum, with significant opportunity for appropriately interleaved practice is essential to develop sufficient competency to attempt the complexity of titrations.

2. Test prerequisite knowledge

While a carefully sequenced curriculum should ensure that your students are primed and ready to grasp titrations, there are no guarantees. 

Therefore, beginning this topic with a quiz to test students’ memory of each of the key ingredients to titrations will provide a view of the classroom landscape: It is inevitable that the results of this will vary from student to student, class to class, so having a plan B in place (if their knowledge isn’t sufficient) is equally import.

This plan B gives the opportunity for extended practice and mastery of skills for those who have retained prior knowledge, while the students who haven’t yet embedded concepts in their long-term memory have the opportunity for reteaching, further practice and retrieval to ensure that knowledge is embedded.

So, your plan B may consider: how will you reteach balancing equations? What if some students in your class can manipulate equations, but many can’t? How will you make that learning time equitable for everyone in the class? Is whole-class research necessary? Will you need to do small group teaching while others practice problems? Will a teaching assistant support those who are confident, while you teach the group who are yet to achieve this?

3. The big picture

Once you are confident that students are able to perform the preprequisites, and when everyone has been given opportunity to demonstrate success, it is an appropriate time to introduce titrations calculations. 

If you need a quick refresh on titrations, here is a popular YouTube video explaining the topic:

This is where your subject hinterland (anecdotes to set the scene for the topic) really come into play. By taking real-life, tangible examples, from the real word of students, it provides the hook upon which to start growing their schema further. Instead of the “so what?”, it is “oh, yeah!” - they get the relevance of that aspect of learning.

Give students the opportunity to see that titrations can be used to identify unknown substances and have been used in forensic history in criminal cases. This is a hook, an engager, which piques their interest and allows them to see that chemistry is real, it is the world around us.

4. I do / we do / you do

As with many aspects of science teaching, effectively planned modelling can provide the perfect platform from which students’ learning can take huge leaps.

Utilising Doug Lemov’s I do / we do / you do technique can pay dividends:

I do: Providing students with a problem to solve, you, the class teacher, talks through the question, detailing your thought process, what knowledge you would draw upon, and exactly how you, the expert, would solve it. Students follow this process carefully, and annotate their own copy of the same problem, exactly as you have.

We do: Both the students and teacher have copies of further problems. This time, the problems are being solved together, with a carefully planned series of questions, targeting all members of the class to collectively solve the problem. It gives everyone the chance for success, to demonstrate their understanding, and it is also an opportunity to identify any misconceptions that may have developed.

You do: Once everyone is ready to fly solo, they can solve their own problems independently, with teacher input as and when necessary.

This provides a structured scaffold, upon which students can build confidence, while gaining independence and moving towards automaticity.

Louise Lewis is a research lead and deputy head of science in a Yorkshire secondary school. She tweets @MissLLewis