Plastic straws are banned — and the shelves are suddenly full of paper, rice, sugar-cane and pasta replacements. But are they any good? Do they survive a drink, and are they really better for the planet? In this free investigation, students decide for themselves. First they work out what "best" even means — most durable? most affordable? quickest to break down? — then design their own enquiry, combining hands-on testing with research to reach an evidence-based verdict.

Along the way they put real curriculum science to work — the properties of materials and what makes them biodegrade — measuring how much mass and structure a straw loses over time, testing strength and durability with forces, controlling variables, and weighing up how valid their methods are (does boiling water really mimic decomposition in soil?). It applies and deepens content students have already met, in a context they actually care about, so it consolidates the curriculum rather than taking time from it.

It also builds the 'Working Scientifically' skills that count at GCSE: planning investigations, evaluating claims, analysing data and constructing evidence-based arguments. Because students plan and run a whole enquiry rather than follow a recipe, they develop the grasp of how investigations work that pays off in AO3 exam questions set in unfamiliar practical contexts — where marks are hardest won.

It works for every student, too: the presentation guides the class through each step of thinking like an investigator — turning the issue into a clear scientific question, breaking it into smaller ones, deciding how to gather evidence, and judging which sources to trust — so genuine independent enquiry is within reach of the whole class, not just the most able.

You choose the depth — a choice of investigations from fully structured to entirely student-designed, all achievable with standard or low-cost equipment:

• Investigation A — Biodegrading: a longer, fully structured soil study with a complete method, or a shorter boiling-water version for students to adapt
• Investigation B — Straw properties: an open investigation for students to design themselves

It's quick to prepare and flexible to fit: run it as a focused mini-project, or split the pathways between groups and pool the findings. The shorter pathways slot into a lesson or two; the longer biodegradation study plays out over a few weeks, needing only a few minutes' observation each week. Everything's done for you:

• Presentation: introduces the challenge, sparks discussion and guides students through each step
• Teacher & Technician Guide: running notes for the presentation and every pathway, plus full equipment lists

Free to download, use and adapt. No scheme of work or special training required.