Today I carried out an awesome activity with my Year 8’s to cap off our topic on separating mixtures. We’ve already gone through examples of each separating technique, from filtration to crystallisation, sedimentation to magnetic separation.
To help consolidate their skills in separating a range of mixtures, I thought I’d take inspiration from MasterChef’s Mystery Box challenge. I created a list of 8 different mixtures:
Rice and salt
Salt crystals and herbs
Peppercorns and herbs
Coffee grounds and water
Iron filings and salt
Salt and canola oil
Tea leaves and water
Rice, salt, peppercorns and herbs
Each of these was under a numbered box at their benches. At the front was a “pantry” of general separating equipment – filter funnels and paper, gauze mats, Bunsens, beakers, measuring cylinders, sieves and so on. They chose a number out of a hat and then had to reveal their mixture from under the box. They could separate their mixture into its components however they liked using the pantry equipment and anything else they needed.
It was fantastic! They were so engrossed in what they were doing – negotiating, problem solving, writing and rewriting their ideas on their whiteboards, arguing and debating the best approach to the problem. On one hand some groups wanted to cut corners, but on the other hand others were being super meticulous in trying to separate every skerrick. Here’s one group’s effort with the peppercorns and herbs, showing the “mystery box” in the background: