1. Learn the stability principle of triangles;

2. Build a triangular bracket with pegs, beams, and axles by hand.

1. Understand the center of gravity and factors affecting the balance of objects;

2. Understand the impact of the center of gravity on the balance, by changing the position of the balancing bird's gravity center.

1. Understand and learn the simple mechanical structure -wheel and axle structure, and understand its advantages;

2. Understand the wheel rotates with the axle when the axle rotates.

1. Understand the concept of elastic potential energy and how it is stored and released in a rubber band.

2. Understand how elastic potential energy is converted into kinetic energy of the slingshot by observing the shooting process of a slingshot.

1. Learn the structure and one-way rotation characteristics of the ratchet wheel and pawl;

2. Explore the application effect of the ratchet wheel and improve the user's hands-on ability through the actual operation of the revolver.

1. Learn the characteristics of the worm drive, self locking, and direction conversion;

2. Control the lifting and lowering of the forklift's arm by turning the worm drive to learn the characteristics of the worm drive.

1. Understand the centrifugal motion of an object during rotation;

2. Feel the centrifugal motion directly by constantly turning the handle to speed the flywheel up.

1.Learn how the pull-back device works;

2. Operate the pullback car to deeply understand the relationship between force, motion, potential energy, and kinetic energy.