If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

### Course: Class 11 Physics (India)>Unit 19

Lesson 1: Introduction to waves

# Transverse and longitudinal waves review

Overview of key terms and skills for waves, including how to identify longitudinal and transverse waves.

## Key terms

TermMeaning
WaveAn oscillation that transfers energy and momentum.
Mechanical waveA disturbance of matter that travels along a medium. Examples include waves on a string, sound, and water waves.
Wave speedSpeed at which the wave disturbance moves. Depends only on the properties of the medium. Also called the propagation speed.
Transverse waveOscillations where particles are displaced perpendicular to the wave direction.
Longitudinal waveOscillations where particles are displaced parallel to the wave direction.

## How to identify types of waves

In a transverse wave, the particles are displaced perpendicular to the direction the wave travels. Examples of transverse waves include vibrations on a string and ripples on the surface of water. We can make a horizontal transverse wave by moving the slinky vertically up and down.
In a longitudinal wave the particles are displaced parallel to the direction the wave travels. An example of longitudinal waves is compressions moving along a slinky. We can make a horizontal longitudinal wave by pushing and pulling the slinky horizontally.

## Common mistakes and misconceptions

Sometimes people forget wave speed isn't the same as the speed of the particles in the medium. The wave speed is how quickly the disturbance travels through a medium. The particle speed is how quickly a particle moves about its equilibrium position.

For deeper explanations of transverse and longitudinal waves, see our video introduction to waves.
To check your understanding and work toward mastering these concepts, check out the exercise on identifying transverse and longitudinal waves.

## Want to join the conversation?

• Is there an easy way (an acrostic or something) to remember what wave is bunched together and which has up and down movement?
• I find that the 'long' in longitudinal reminds me a bit of 'along'. As in along the medium. While the 'trans' out of transverse is more readily used in various fields and comes from Latin and translates to 'the other side of'. So it travels from one side to the other side. Hope it helps.
• here its written "Sometimes people forget wave speed isn't the same as the speed of the particles in the medium" but wont the increase in particle speed increase wave speed
• Nope, increasing particle speed does not increase the wave speed. They are separate. Actually it elaborated right after the sentence you quoted. 'The wave speed is how quickly the disturbance travels through a medium. The particle speed is how quickly a particle moves about its equilibrium position.' An increase in particle speed will increase the energy the wave carries but will not affect the wave speed at all.
• So if you move the slinky forwards and backwards, then the slinky with get bunched up in some places, like how the air was in the sound wave from the video, creating a longitudinal wave? But if you move it up and down, then the slinky with go up and down until you stop, like the string in the video, creating a transverse wave?
• Yes. Imagine ripples in water is a longitudinal wave, and transverse waves are those waves like when you shake a string and the curve continues along the string.
• So when a transverse and longitudinal wave combine, what is that called?
• Longitudinal and transverse waves can combine to form what is known as a surface wave. One common example of this combination is the Rayleigh wave. In a Rayleigh wave, particles move in an elliptical or circular motion, combining both the back-and-forth (transverse) and compressional (longitudinal) motions. This kind of wave is frequently seen during seismic activity and plays a part in the surface of the earth trembling during an earthquake.
• If a wave length is so short, (gamma rays) can it be detected by machines? What are the effects of waves on a medium?
• yes it can be detected and a wave
• Hi, I would like to ask about classifying waves. So waves are divided into 2 types: mechanical (e.g.: sound waves) and non-mechanical (e.g: light waves). Mechanical waves are further divided into transverse waves and longitudinal waves. Why are light waves longitudinal, yet they aren't considered mechanical? Thank you.
• Mechanical waves must travel through matter. Electromagnetic radiation (e.g. light) can travel through a vacuum, thus it is not a mechanical wave.
(1 vote)
• what happens if both types of waves are mixed together.
• Longitudinal and transverse waves can combine to form what is known as a surface wave. One common example of this combination is the Rayleigh wave. In a Rayleigh wave, particles move in an elliptical or circular motion, combining both the back-and-forth (transverse) and compressional (longitudinal) motions. This type of wave is often observed in seismic activity and contributes to the shaking of the earth's surface during an earthquake.
(1 vote)
• how does waves move through a medium?
(1 vote)
• If you are talking about physical waves, such as sound waves and vibrations, here is the answer. As the wave passes through a material, the particles at the wave are moving a very small distance. As they move, they bump into other particles and impart their momentum onto these new particles. These new particles in turn move and bump into other particles, repeating the cycle of movement and imparting momentum, thus allowing the wave to move through the medium.