In the following example, you will see an oscilloscope depicted.  Click on the Play button to hear a sound.  The sound you are hearing is a pure electronically generated "sine" tone.  Its waveform is depicted in the oscilloscope display, along with the frequency in Hz (1397 Hz) and the amplitude.

Beneath the oscilloscope display there are some buttons.  Click the buttons to change the amplitude of the sound.  As you click the Amp. Higher button, you will notice that the sound of the tone you are hearing gets a little louder.  Meanwhile, you will observe that the height of the waveform depicted in the oscilloscope gets taller--that is, its amplitude is increased.