A: Chord is a tiny vibration energy (on or off).

Q: Are strings particles?

A: No, strings are linear energy. The particles are punctate.

Q: Does a string have mass and volume?

Answer: there is mass (because mass and energy are the same characteristics of matter, but they are expressed in different ways). The length of a string is Planck's length, which is 10 minus 33 cm.

Q: What are the strings made of?

A: String is the most basic unit in the universe, and it is a piece of energy.

Q: Will the string die or disappear?

A: Matter can disappear out of thin air, as long as the sum of positive and negative matter remains unchanged and does not violate the conservation of mass and energy. In addition, the closed string can disappear from our universe and penetrate into hyperspace.

Q: Can you make strings?

A: At present, we can't observe strings, let alone make them, but I believe we can in the future, because the universe is more magical than we thought. What is emphasized here is that matter can be produced out of thin air or disappear out of thin air, as long as the total amount of matter remains unchanged.

Q: What is the vibration frequency of the string?

A: Strings have different vibration frequencies, and different frequencies are different particles in our view. The only difference between the strings that make up us and the strings that make up light is the different vibration frequencies.

Q: Is the string a closed circle?

A: The latest version of string theory M theory (obtained by edward witten unifying five different string theories and 1 1 dimensional supergravity) tells us that the string that constitutes the graviton is a closed string (circle).