The reason why no sound can be heard when the steel ruler extends out of the tabletop is that the frequency of the sound is lower than 20Hz.

It is difficult for objects with large volume and mass to vibrate, with low frequency and low pitch. The frequency range that humans can hear is 20-20000Hz.

As the length of the steel ruler protrudes from the tabletop, the volume and mass of the vibrating part increase, making it harder and harder to vibrate, the frequency becomes smaller and smaller, and the pitch becomes lower and lower. If the steel ruler extends beyond a certain length from the table, it is difficult to vibrate. The frequency is less than 20Hz and cannot be felt by the human ear.

About the human ear

A variety of sounds can be heard, including natural sounds, human voices, music, traffic noise, etc. In fact, the human ear is very sensitive to sound, and the sound range we can hear is approximately between 20Hz and 20kHz.

When sound enters our ears, it first passes through the outer ear, ear canal and eardrum, then is transmitted to the middle ear and inner ear, and finally is converted into nerve signals and transmitted to our brain for processing. The process is complex but very quick. Everyone's hearing abilities may vary, and some people may be more sensitive to sounds in certain frequency ranges and less sensitive to others.

So, when we hear a sound, our brains immediately decode and analyze it, and then we can understand what the sound represents. For example, when we hear the whistle of a train, we immediately recognize that it is a signal that the train is about to leave, and when we hear the voice of a friend, we immediately recognize that he or she is talking to us.

About steel ruler

Steel ruler is a common measuring tool, usually made of metal materials and has a certain hardness and durability. Its main function is to measure the length of line segments and can be used for various measurement tasks in daily life or work. Steel rulers usually have graduations that allow direct reading of length.

The advantage of the steel ruler is that it has high accuracy and stability and can provide accurate measurement results. The scale of the steel ruler is clearly visible, making it easy to read and use. The material of the steel ruler is strong and durable, not easily deformed or damaged, and can be used for a long time.

Steel rulers are usually longer in size and are suitable for measuring larger objects or distances.

The price of steel rulers is relatively low, and ordinary people can easily buy and use them. The steel ruler is a practical measuring tool that offers accuracy and durability for a variety of measurement needs. Whether in home life or at work, the steel ruler is an indispensable tool.