Common musical instruments:

1. Piano: The piano is a keyboard instrument played with a black and white keyboard. It can play solo, accompaniment and ensemble, and is one of the indispensable and important instruments in bands and orchestras.

2. Guitar: The guitar is a plucked instrument, usually played with fingers or a pick. It comes in different types and sizes, including classical guitars, folk guitars, electric guitars, etc., suitable for playing various styles of music.

3. Violin: The violin is a stringed instrument played with a bow. It is one of the main instruments in the orchestra and is also commonly used for solo and chamber music performances.

4. Flute: The flute is a wind instrument that makes sound by blowing air. It comes in different materials and modes, including flute, piccolo, transverse flute, etc., and is suitable for playing folk music and classical music.

5. Drum set: The drum set is a percussion instrument composed of multiple drums and cymbals. It is usually used for accompaniment and rhythm band performance, and is one of the indispensable and important instruments in modern pop music.

The unique characteristics of musical instruments:

1. Physical principles: All musical instruments produce sound based on physical principles. For example, stringed instruments produce sound by vibrating strings, wind instruments produce sound by vibrating airflow, and percussion instruments produce sound by vibrating air.

2. Pitch and timbre: Each musical instrument has its own unique pitch and timbre. The pitch determines the melody that the instrument can play, while the timbre determines the emotional expression of the instrument when played.

3. Performance skills: Playing an instrument requires mastering certain skills, such as the coordination of fingers, arms, feet and other movements, as well as the control of strength and rhythm.

4. Emotional expression: Musical instruments are not only tools for playing melody, but also a means of expressing emotions. Through the playing of musical instruments, emotions such as joy, anger, sorrow, and joy can be conveyed.

5. Culture and history: Many musical instruments have rich cultural and historical backgrounds, such as classical musical instruments and traditional Chinese musical instruments. These backgrounds add more cultural connotation to the performance of the instrument.

6. Diversity and innovation: There are many types of musical instruments, and each instrument has its own unique expression and playing skills. At the same time, with the development and evolution of music, new instruments are constantly emerging, such as synthesizers and electronic instruments.