The principle that chopsticks can lift a rice cup is that the greater the object pressure, the greater the friction. There is friction between objects. When an object is forced to move, friction will hinder the object from moving in the opposite direction. The rice in the cup horizontally squeezes chopsticks under the action of gravity, and gravity squeezing increases the friction. When the friction is greater than the downward gravity of the rice in the bottle, chopsticks can lift the bottle.

Examples of increasing friction in life:

1, the sole has uneven patterns. Under the condition of constant pressure, the friction force is increased by increasing the roughness of the contact surface.

2. Sticking rubber on the table tennis bat makes the contact surface rough, which can increase the friction force under the condition of constant pressure.

3, the car is stuck in the mud, plant grass to let the car out and increase friction.

Examples of reducing friction:

1. Adding lubricating oil to bicycle axles reduces friction by separating the contact surfaces from each other.

2. Wheels are installed under the suitcase, which is convenient and labor-saving, reducing sliding friction and belonging to rolling friction.

Refueling the clock can reduce friction and make the time more accurate.