Fully Comprehensive simple machines set for middle school. Contains 1432 pieces and color-coded building instructions to build 30 different models. Build 4 of each/any model type simultaneously. Models demonstrate: 1st, 2nd and 3rd class levers; fixed, movable, compound and block and tackle pulley systems; wheels and axles with the force applied to both the wheel and the axle; inclined planes, screws and wedges; spur, crown, sprocket, rack and pinion, transmission and differential gear systems. A 70 page teacher's guide is included in the set; 14 student inquiry lesson plans and worksheets, plus teacher answer sheets.Teacher's Guide Included.