Extended techniques have changed the way we play string instruments today. They go beyond the usual way of playing to create exciting new sounds. Let's look at some cool techniques that are becoming popular in modern music.

1. Pizzicato Variations

• Bartók Pizzicato: This is when musicians pluck the string sharply. It makes a snapping sound that adds a cool rhythm.
• An example of this is in Bartók's "Concerto for Orchestra," where this technique creates a striking difference in sound.

2. Harmonics

• Natural Harmonics: This happens when you lightly touch the string at certain spots. It makes soft, airy sounds.
• Artificial Harmonics: For this, you press down on a string and lightly touch it higher up. This technique is beautifully shown in Ligeti’s "Sonata for Solo Viola."

3. Bowing Techniques

• Col legno: Here, musicians use the wooden part of the bow to play. This creates spooky, ghost-like sounds. Morton Feldman often uses this technique in his music.
• Sul ponticello: This technique involves bowing close to the bridge of the instrument. It gives a glassy, haunting sound. Composers like Kaija Saariaho use this very well in their pieces.

4. Multiphonics

• Musicians can place their fingers and bow in specific ways to play multiple notes at the same time. This creates a rich, layered sound. You can hear this in George Crumb’s "Black Angels."

These extended techniques let musicians and composers discover new sound worlds. They bring more ways to express feelings using string instruments in today's music.