Compression Wave: Definition & Overview

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Continuous Spectrum: Definition & Overview

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:00 The Importance of Waves
  • 0:25 Slinky Example
  • 1:07 Features of Longitudinal Waves
  • 2:15 More Examples of…
  • 3:11 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Speed Speed

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: David Wood

David has taught Honors Physics, AP Physics, IB Physics and general science courses. He has a Masters in Education, and a Bachelors in Physics.

This lesson will define longitudinal (or compression) waves, discuss the names for various features and parts of a longitudinal wave, and go through some examples of longitudinal waves in the world. A short quiz will follow.

The Importance of Waves

Waves carry energy, and in the case of earthquake waves, they carry huge amounts of energy. The first thing you feel when an earthquake hits is a longitudinal wave, and every sound you hear is a longitudinal wave. Waves are everywhere in nature and understanding them is an important part of explaining the world as a whole.

Slinky Example

Longitudinal waves, also known as compression waves when describing waves in mechanical terms, are waves where the vibration is parallel to the direction the wave is moving. That might be hard to picture, which is why we need some help from a Slinky.

It looks something like this:

A Longitudinal Wave in a Slinky

A longitudinal wave is what you get if you push a Slinky along its length, sending a pulse down it.

The other type of wave is called a transverse wave. A transverse wave looks something like this.

A Transverse Wave in a Slinky

A transverse wave is a wave where the vibration is at right angles to the direction the wave is moving. That's what you get if you move the Slinky from side to side, sending a wave along it.

Features of Longitudinal Waves

There are a few features we can label on a longitudinal wave, as shown in the diagram onscreen now:

Features of Longitudinal Waves

A compression is the part of the wave (or Slinky) that is pressed together -- this is like the crest or peak of the wave. A rarefaction is the part of the wave (or Slinky) that is the most spread apart -- this is like the trough of the wave.

You can see how these compressions and rarefactions can be considered as crests and troughs if we plot a graph of particle density against position for a (longitudinal) sound wave shown.

Longitudinal Wave Pressure Graph

As you can see from the diagram, the particle density varies in a perfect wave shape. This is how we know that longitudinal 'waves' are really waves.

This diagram allows us to measure another feature of longitudinal waves -- the wavelength. A wavelength is the distance from two similar parts of a wave—from a peak to the next peak or from a trough to the next trough. It is the length of one full wave, one full oscillation. Wherever you measure it, the number should come out the same.

Other Examples of Longitudinal Waves

Most waves in the universe turn out to be transverse waves, but there are a few examples of longitudinal waves.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account