The handle of the bicycle bell is moved by hand, which drives the gear. The gear is rotated by a shaft with a spring hammer. The bell will ring when the spring hammer hits the bell cover. Bicycle bells can make sound because vibrating objects can make sound. If you press the bell cover with your hand, the bell will stop vibrating.

The phenomenon of light

The reflective surface of bicycle taillights is composed of many red cube right angles, which can reflect the light shining on the taillights in all directions, so that people in all directions behind the car can see the red light and prevent traffic accidents.

Friction phenomenon

1. Rolling bearings and lubricating oil are installed on the front axle, middle axle and rear axle of the car, and the wheels are round to reduce friction.

2. The tires, plastic handlebars and pedals of the car are all engraved with patterns, and there are grooves on the handlebars of the car to increase the roughness of the contact surface and increase the friction.

If the bell doesn't ring, it's because the meshing part between the shaft and the gear is too rough. Add a few drops of oil for lubrication to reduce friction.

4. The plastic sleeve of the handlebar is tightly sleeved on the handlebar sleeve to increase the pressure with the handlebar sleeve and increase the friction.

5. When braking, clamp the brake hard to increase the pressure and friction.

6. Tighten all kinds of fastening screws of bicycle to increase pressure and friction.

7. The front wheel of a bicycle is a driven wheel, and the direction of friction is backward, which is opposite to the direction of movement. The rear wheel is the driving wheel, and the direction of friction is forward, which is the same as the direction of vehicle movement. During emergency braking, the friction between the wheel and the ground belongs to active friction.

Pressure phenomenon

1. The bicycle cushion is saddle-shaped, which can increase the contact area between the cushion and the human body and reduce the pressure on the buttocks.

2. The pedal is very wide to increase the contact area with the foot and reduce the pressure on the foot.

3. The tire made of rubber is inflated to reduce the pressure on the ground, and at the same time it can play a buffering role through elastic force.

4. When inflating a tire, the harder you pump it, the harder it will be, because the greater the gas inside, the greater the pressure inside.

Thermal problem

1. In summer, bicycle tires will be completely deflated. If you park in the hot sun, the tire will burst. Because under the scorching sun, the temperature in the tire increases and the pressure increases, when the pressure increases to exceed the maximum pressure that the tire can bear, the tire will burst.

2. When bicycle tires are inflated with a pump, the wall of the pump will heat up in a short time, because the piston of the pump compresses gas to do work, and the gas can increase in its body and be transferred to the cylinder wall, which is the increase of wall temperature. At the same time, the atmospheric process is also a process of overcoming the friction between piston and cylinder wall, and also a process of increasing the internal energy and temperature of cylinder wall.

inertia

When riding a bicycle, due to inertia, when the pedal is not pressed hard, the bicycle will continue to move forward. In addition, when riding a bicycle over obstacles, the rear wheel should land first when landing, to prevent rollover due to inertia. When riding a bicycle uphill, you have to step on it and push it a few times before you can improve your speed, gain more kinetic energy, consume more gravitational potential energy and live higher.