After the intro activity have students complete the following sentence starter: "I think that I can slow down or prevent apples from turning brown by ___________________________. It will slow down or prevent the apple from turning brown because ________________________________" (see attached student hand-out). For students in lower grades, testing one possible way to prevent browning might be sufficient. Older grades could test several ways and compare their effectiveness. Show students all the available materials and ask them to design a simple experiment to test their ideas. Students should work in small groups, preferably pairs to work on this. Depending on how experienced the students are in designing their own experiments, more or less scaffolding is needed. Classroom discussions about the importance of control experiments as comparison and about what constitutes a "fair test" as well as supporting the planning process with a template (see attached for sample) might be needed.
Depending on the grade level and experience of the students, the data collection can be more or less "sophisticated". Students can simple record time at which the apples are cut into pieces and at which time they notice each of the apples beginning to brown. At certain time intervals, students can record qualitative data (darkness of color, percentage of coverage on apple, etc.) and/or quantitative data (a ranking of the six different conditions from lightest brown (1) to darkest brown (6)). Students will record their results in data tables they created or on a provided template, again depending on the situation. Another idea is to have the students take photos of the apples at certain time intervals to capture the browing progression and to compare different treatments more accurately. Students can use photos in their final presentations and/or in their lab report (if done).
In Europe, Chematur Engineering AB of Sweden commercialized the SCWO technology for treatment of spent chemical catalysts to recover the precious metal, the AquaCat process. The unit has been built for Johnson Matthey in the UK. It is the only commercial SCWO unit in Europe and with its capacity of 3000 l/h it is the largest SCWO unit in the world. Chematur's Super Critical Fluids technology was acquired by SCFI Group ( Cork, Ireland ) who are actively commercializing the Aqua Critox SCWO process for treatment of sludge, . de-inking sludge and sewage sludge. Many long duration trials on these applications have been made and thanks to the high destruction efficiency of %+ the solid residue after the SCWO process is well suited for recycling – in the case of de-inking sludge as paper filler and in the case of sewage sludge as phosphorus and coagulant. SCFI Group operate a 250 l/h Aqua Critox demonstration plant in Cork, Ireland.