Much of what we learn, we forget. Whether this is over a summer holiday, or over the course of many years. Some knowledge we retain more because of repetitive learning, or because it sticks with us in a very personal manner, say due to passion and interest. As your child progresses through primary school, a lot of what we teach them, they will not necessarily remember. This is why I say focus on the fundamentals.
Children learn at an incredible rate, they can learn things in greater complexity than they usually get credit for. If you are patient and give room for inquiry, you will find that students are able to go to depths most would not expect. When you go to this depth of learning with them, they will build a much more robust framework of knowledge so that even if they forget the specifics and details, they will be able to piece them together on their own again.
I find this particularly true in Science. In Term 1 of this year, I taught Flight and Rocketry to my Grade 6 students. There is a wide array of knowledge that students could take away from this course. For example, the four forces that we consider as affecting flight: thrust, gravity, lift, and drag. They could know what Bernoulli's principle is, but more than anything else, if every student could leave my class understanding the very first lesson which was principles of air, I would go home a happy teacher.
Students deserve depth. The curriculum styled the lesson as Principles of Air, but in reality they were learning an introduction to Fluid Dynamics. So that is what we learned. Water and air behave in a similar fashion. We dove into understanding a molecule (similarly, dive into an atom when learning electricity), and they asked questions that I had to work to answer. “What exists between molecules?” “If gravity comes from mass, what is gravity like at the exact center of the Earth?” Sure, it may take time but when a student truly understands the basic principles of air (it is made of molecules, it has mass which gives it weight, it takes up space), they can relearn everything else again and again.
Diving into fundamentals also moves us away from crutches in teaching. It pushes us to further our own understanding. Hot air does not rise because it is hot. It rises because when energy is applied to it, the molecules making up our air move around more and more. This makes the hot air less dense, which in turn means there is less of it in any given space, and it is therefore lighter than cooler air. That is a much more complicated answer than “hot things rise”, but it is the answer students deserve, the only price we pay is time.
If a student forgets the four forces, but remembers simply that air is made of molecules, they can reimagine the interaction a flying object will have with those molecules. They might forget the name, but they will maintain a framework for understanding the concept.
It is easy to take the introduction of content for granted, to skim over it as a necessary prerequisite to greater or more knowledge, more demonstrable vocabulary. But building the time in to really dive deep into those basics will be significantly more rewarding in the long run.