Look around you carefully, and you’ll notice: mechanical waves are everywhere. On the surface of a lake, in the motion of branches, in the shape of clouds, dunes or hills. You can even find waves in the distortion of space time emitted during the collisions of black holes!

But what are these waves exactly? Are these just a shape that humans categorise and therefore, in some way, invent? Or are waves a fundamental construct of nature?

Using classical physics concepts only, I will attempt to discuss the fundamental nature of waves, and even give a shot at a nonexhaustive definition. In other words, don’t expect a straight forward answer, but a bunch of clues that will allow you to pursue your own thoughts on this physicophilosophical interrogation.

At first, I show how a wave is formed by applying a motion to an oscillator bonded with other oscillators (particles in a rope). That’s to show how a wave can emerge. I also discuss briefly the notion of emergent property.

Second, using Newton’s laws, I demonstrate that the motion in time of an oscillator is described by a cosine (or sine) curve, in other words a wave.
I connect the 1st and 2nd parts and realise that what I saw at first as an emergent shape was actually a macroscopic expression of a microscopic natural phenomena. Waves do appear as a fundamental building block of physics!

Finally, I discuss the role of waves in Physics: they transport energy from one point to another. They indeed appear as a crucial phenomenon needed to make the Universe as it is!

*** LINKS ***
Video of Alan Watts:    • Alan Watts: A Conversation with Mysel...  
What is Temperature? :    • What is Temperature? (1 minute of phy...  
What is Work? :    • What is Work? (High School Physics)  
What is Energy? :    • What is Energy?  

*** Content of this video ***
0:00 What is a Wave? Introduction: waves are all round us
1:31 What is a wave? Is it just an emergent shape?
4:22 What is an emergent property?
5:33 What are waves? Are they a fundamental construct of nature?
10:22 Waves and Energy, what’s the link?
14:32 What are waves. Conclusion and food for thoughts.

*** Credits ***
Portrait of Alan Watts CC BY 2.0, Libertarian Girl, https://www.flickr.com/photos/brookeb...
Music by Edouard Reny.

*** More Info ***
This video is produced and presented by Edouard Reny, Ph.D. in solid state chemistry and private tutor in Physical Sciences.

For access to great resources that will help you with your studies of high school Physics, visit and subscribe to the "Physics Made Easy" website:
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Edouard provides oneonone private tuition in Physics (face to face or by Skype). If you wish to contact him, visit his website: https://www.physicstutor.nl/