Questions

The first scientific question I am investigating is, How is sound made?

The second scientific question I am investigating is, What determines the pitch of a sound?

Data/Evidence

The tuning forks vibrated.

When you stopped the vibration, the tuning forks stopped making sound.

The string on the Violin vibrated when played.

The string on the Ukulele also vibrated when played.

The singers vocal cords vibrated when she sang.

The large tuning fork sounded low.

The small tuning fork sounded high.

The drum vibrated when hit.

The cymbals vibrated when hit too.

Analysis 

All of the instruments vibrated when making sound.

The smaller tuning fork vibrated 2 times faster than the large tuning fork. We saw this on the scratches on the aluminum fol.

Claims

Sound is caused by vibration.

The speed of vibration determines the pitch.

Reasoning

My research suggests the sound is caused by vibration, because every instrument vibrated when making sound.

My research suggests that pitch is determined by the speed of vibration, because the small tuning fork vibrated two times faster then the large tuning fork and sounded higher.

Significance

This means if i want to build a machine that can make any sound, it must be able to vibrate at any speed.