The snow in the crystal ball will fly because of the principle of magnetic levitation. Magnetic levitation technology controls the changes in the magnetic field to rotate the snowflake powder suspended in the crystal ball, thereby generating a rotating magnetic field. This causes the snowflake powder to fly in the rotating magnetic field, making it look like it is flying in the air.

To make such a crystal ball, you need the following materials:

1. A transparent glass ball that can hold water and small snowflakes.

2. Magnetic levitation system: includes a magnet and corresponding control circuit. This magnet spins inside the glass ball, creating a rotating magnetic field that causes the snowflakes to fly.

3. Music device: It can be a small music chip or a device that can play music. The device needed to be able to synchronize with the magnetic levitation system so that the snowflakes would fly as the music played.

4. Small snowflakes: These small snowflakes can be purchased in stores. Typically made of polystyrene, they are lightweight and capable of flying around in rotating magnetic fields.

During the production process, you first need to fill the glass ball with water, and then add small snowflakes. Next, the magnetic levitation system and music device were attached to the glass sphere, and the magnets were placed inside the sphere. Finally, adjust the parameters of the magnetic levitation system and the music device so that they can work in sync so that when the music is played, the small snowflakes can fly with it.