Question

I want to carry out liquid recognition. I want to use a speaker as a sound source to generate vibrations (by playing sounds of different frequencies). My idea is that different liquids have different resonant frequencies. When the frequency of the external force is close to the resonant frequency of the liquid itself, the liquid's The amplitude will be larger, so different liquids can be identified. I would like to ask you if my idea is reliable and can you tell me some theoretical knowledge, such as whether the amount of liquid also affects the resonant frequency?

Answer 1

Yes, your idea of using resonant frequencies to identify different liquids is reliable. The amount of liquid can affect the resonant frequency.

Step-by-step explanation:

Yes, your idea of using resonant frequencies to identify different liquids is reliable. When the frequency of an external force, such as the vibrations from a speaker, is close to the resonant frequency of a liquid, the liquid's amplitude will be larger. This can be observed in examples such as waves on the surface of a wine glass and musical pitches created by blowing across the surface of a small-necked bottle with water.

The amount of liquid can affect the resonant frequency. In general, adding more liquid to a container will increase the depth of the liquid, changing the length of the resonating column and thereby changing the resonant frequency. Therefore, the amount of liquid can be a factor in identifying different liquids based on their resonant frequencies.