It’s fun and relaxing to throw pebbles into otherwise still water and watch the ripples form and grow.  I love watching the concentric rings overlap and form patterns as you throw more.  

What causes these beautiful round repeating and growing waves?  Here’s my…

Super-duper basic explanation of what causes ripples 

Water has surface tension so it has a kind of elastic property. When the rock hits the water it bounces the surface down a bit and like a ball it comes back up.  And just like a ball it does this a bunch of times before gravity restores the water’s equilibrium and the water is still again.

When the rock hits the water and it is met with some resistance, the surface is displaced not only down but outward as well.  Then the disturbance is transferred from one water molecule to the next (the way a rolling ball hitting another ball will cause it to roll) and a radial wave forms.  This process continues to repeats as long as the center continues to “bounce”.  

Learn more about waves here.

Make your own simple small ripple tank!  

Here you can also see the waves bouncing off the sides.

If you don’t have the right conditions to observe ripples outside how about creating a simple small ripple tank in your kitchen.

Put water in a glass Pyrex pan and place it on white paper. To increase the visual contrast, increase the distance between the pan and the white paper.  I used another Pyrex pan turned upside down.   It is hard to observe the ripples in motion at this scale because it happens so fast.  Instead try taking pictures as you add droplets of water to the pan.  In the picture you will see the ripples clearly.  It’s amazing!

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