Use red onion when teaching students how to use a microscope.
Prepared slides are expensive and easily broken, particularly by excited year 7s. Before you teach your students how to mount a slide with iodine and cover slips, teach them how to focus a microscope using red onion.
- Peels very easily;
- Requires no staining;
- Are much smaller than white onions (less wastage).
How do you teach microscopy?