How about giving books about waves or the ocean to your loved ones?
We have an illustrated book about waves specifically for kids, or a photo guide to wave watching for anyone — both available in English or German!
Or if you don’t have access to puddles, rivers, lakes, or the sea, or would like a little structure to explore the oceans in, check out the 24 days of #KitchenOceanography book! Works great as advent calendar with one experiment every day, or as a I-want-to-pick-and-do-an-experiment-now book!