Mechanical waves need a medium: Unlike electromagnetic waves, mechanical waves cannot travel through a vacuum. They need a medium like air, water, or solids to move.

Two main types: Mechanical waves come in two primary forms: transverse and longitudinal. In transverse waves, particles move perpendicular to the wave's direction, while in longitudinal waves, particles move parallel.

Sound waves are longitudinal: Sound waves are a common example of longitudinal waves. They travel through air by compressing and rarefying the particles in the medium.

Water waves are transverse: Water waves are primarily transverse waves. The water particles move up and down as the wave travels horizontally.

Seismic waves: Earthquakes generate seismic waves, which are mechanical waves that travel through the Earth's crust. These waves can be both transverse (S-waves) and longitudinal (P-waves).

Energy transfer: Mechanical waves transfer energy without transferring matter. The particles in the medium oscillate around their equilibrium positions but do not move with the wave.

Amplitude and energy: The energy carried by a mechanical wave is proportional to the square of its amplitude. Higher amplitude waves carry more energy.

Frequency and energy: The frequency of a wave also affects its energy. Higher frequency waves have more energy than lower frequency waves of the same amplitude.

Damping: As mechanical waves travel through a medium, they lose energy due to friction and other resistive forces. This loss of energy is called damping.

Reflection and transmission: When a mechanical wave encounters a boundary between two different media, part of the wave is reflected back, and part is transmitted into the new medium.

Interference: When two mechanical waves meet, they can interfere with each other. This interference can be constructive (waves add up) or destructive (waves cancel out).

Diffraction: Mechanical waves can bend around obstacles and spread out after passing through narrow openings. This bending is called diffraction.

Refraction: When a mechanical wave passes from one medium to another, its speed changes, causing the wave to bend. This bending is known as refraction.

Resonance: When a mechanical wave's frequency matches the natural frequency of an object, it can cause the object to vibrate with large amplitude. This phenomenon is called resonance.

Standing waves: When two waves of the same frequency and amplitude travel in opposite directions, they can form a standing wave. In standing waves, certain points (nodes) remain stationary while others (antinodes) oscillate with maximum amplitude.

Ultrasound imaging: Ultrasound waves, a type of mechanical wave, are used in medical imaging to create images of internal body structures.

Sonar: Sonar systems use sound waves to detect objects underwater. This technology is widely used in submarines and for mapping the ocean floor.

Seismology: Seismologists study seismic waves to understand earthquakes and the Earth's interior structure.

Musical instruments: Musical instruments produce sound through mechanical waves. For example, a guitar string vibrates to create sound waves in the air.

Communication: Mechanical waves, like sound waves, are used in various communication systems, such as telephones and radios.

Speed of sound: The speed of sound in air is approximately 343 meters per second (1235 km/h). However, it travels faster in water and even faster in solids.

Human hearing range: Humans can hear sound waves with frequencies between 20 Hz and 20,000 Hz. Sounds outside this range are inaudible to us.

Infrasound and ultrasound: Sounds with frequencies below 20 Hz are called infrasound, while those above 20,000 Hz are called ultrasound. Some animals, like elephants, can hear infrasound, while bats use ultrasound for echolocation.

Echoes: Echoes are reflections of sound waves. When a sound wave hits a surface and bounces back, we hear it as an echo.

Tsunamis: Tsunamis are massive ocean waves caused by underwater earthquakes or volcanic eruptions. These waves can travel across entire ocean basins.

Whispering galleries: In certain circular or elliptical structures, sound waves can travel along the walls, allowing whispers to be heard clearly across the room. These structures are called whispering galleries.

Breaking the sound barrier: When an object travels faster than the speed of sound, it creates a shock wave, resulting in a sonic boom. This phenomenon is known as breaking the sound barrier.

Chladni patterns: When a plate covered with sand is vibrated at certain frequencies, the sand forms intricate patterns called Chladni patterns. These patterns reveal the nodal lines of the standing waves on the plate.