Frame the investigation question: which material is the most absorbent? Review what absorbent means. Using the slide deck, model the fair test set-up: identical cups, the same amount of water, the same time — only the material changes.
Model completing the top of the Fair Test Investigation Template: writing the question, a reasoned prediction, and the three variables (change the material; measure the water absorbed; keep the water amount, time and method the same). Demonstrate a measuring method (weigh before/after; remind students 1 g of water = 1 mL).
As a class, agree the method and the controlled variables. Groups set up their materials and, with teacher check-ins, run the test: same water, same time, measure the amount absorbed for each material, and record in the results table on the template.
Students complete the Absorbency Investigation worksheet (and the shared template): recording results, drawing a labelled column graph, stating which material was most absorbent with data evidence, and evaluating whether the test was fair and how to improve it.
Exit ticket: name the most absorbent material and cite the data that shows it.