Oceans: Currents & Waves
Before we broke out our Wave Maker, we learned a bit about Currents & Waves https://www.youtube.com/watch?v=p4pWafuvdrY&t=42s
The Wave Maker is simply put together using wooden skewers and duct tape. https://windyacresworkshop.blogspot.com/2024/04/experiments-wave-machine.html
You can use equal weight balls of plasticine or cucumber slices to demonstrate the ripple effect.