Hello fellow educators! I am preparing to run the "FossBot Waste Warriors: Smart Recycling Awareness" module. The scenario involves students simulating smart waste monitoring systems by using the ultrasonic sensor to detect fill levels in "waste bins". The preparation requires setting up physical boxes and waste materials like paper and plastic. Has anyone run this with 15-18 year olds in a smaller classroom? What materials worked best for your physical bins to ensure the ultrasonic sensor gives accurate distance measurements without taking up too much floor space?