Waves transfer energy without transferring matter. They propagate from the source in concentric circles.

• Propagation speed depends on the medium
• Amplitude determines wave intensity
• Frequency remains constant during propagation

Diffraction is the ability of waves to bend around obstacles and pass through narrow slits.

• More pronounced when obstacle size is comparable to wavelength
• Behind the slit, the wave spreads out like a fan
• Explains sound propagation around corners

Interference is the superposition of waves from two coherent sources (Young's double-slit experiment).

• Bright fringes - constructive interference
• Dark fringes - destructive interference
• Distance between fringes depends on wavelength

Side view shows the wave shape - a sinusoid that moves through space.

• Amplitude - maximum displacement from equilibrium
• Wavelength depends on frequency and speed
• Higher frequency, shorter wavelength