12-Hole Test Tube Stand for Mixed 30mm and 15mm Tubes, Polyethylene Face Size_26mm Square-topped wooden screw simple-machine model

Square-topped wooden screw simple-machine model with a leverage block

Long-and-narrow 6 by 1-inch plane glass mirrors arrive as 10-packs at ~2mm thickness

and intestines

this metal helix lets stairwell-scale wave-propagation experiments amplify the visibility of standing waves

Transmitter and receiver pair on PP3 batteries with 5m and 10m polymer fiber coils

12-Hole Test Tube Stand for Mixed 30mm and 15mm Tubes, Polyethylene Face Size_26mm Square-topped wooden screw simple-machine modelFlat pack polythene test tube stand with six 30 mm and six 15 mm holes, disassembling for easy cleaning between uses in chemistry classrooms and student laboratories.