"Making student thinking visible" means that we are often recording ideas publicly in the model-based sensemaking classroom. Though at times it makes sense to record ideas electronically (e.g. in the PowerPoint slides), there are many ideas we want ot make continually available to the class as we continue to engage with new phenomena and questions. So, if you are (for example) teaching 5 periods of biology, where do all of the posters go?
It usually isn't practical to display all the iterations of a model for every period on separate posters, and it isn't necessary. Instead, track the ideas of each class on a separate PowerPoint slide, then at the end of the day (or segment), once students are gone, "combine" them into one initial model. Go over the combined model with each class, showing them that all of their ideas are included, but perhaps with slightly different wording since several classes contributed. Often ideas will come up in some classes but not others. It is important to include those ideas, but point them out to the classes that didn't have them on their list. For example, "Period 3 came up with the idea that traits are passed from parents to offspring, but that idea didn't come up in this class. We are including it so that we can think about it and discuss it later as we go along and you can decide if you think it should be included in our final model." It is essential that this combined initial model be displayed on a poster as you move forward, so that you can easily revisit and discuss the ideas as you explore them further.
We almost always revise the initial model along the way, adding, eliminating, or revising its ideas, until we are satisfied with it. The "finalized" version of our model (and of course, models are never really final - so we often refer to it as our "final working model") should be displayed somewhere in the classroom. If wall space is limited, one solution is stringing "clotheslines" across the classroom and hanging posters on them. If that is not an option, and there are truly no alternatives, try to at least display the models that are directly relevant to the model in progress. For example, when you are working on Cellular Respiration, Biosynthesis, and Photosynthesis, it isn't absolutely necessary to have the Population Dynamics and Natural Selection models posted, but it is very important that the Chemical Reaction Model be prominently displayed.
Another tool teachers use to help students keep track of the models developed through the year that doesn't require wall space, is to provide a handout at the end of each model revision sequence on which students write down the final model. Students are expected to keep those in their binders, so they can reference them at any time. Printing these on colored paper (maybe even all the same color) can help students keep track of them and find them easily when needed. An example of a blank model tracking sheet is attached.