Some ideas of the fascinating Physics waves can explain.
Why not pick a question that interests you and have a bit of a research to see if you can apply some of the GCSE knowledge of waves to answer the question. And a few videos, (I've not covered all of these questions yet,) to get you started.
What's the fastest thing in the Universe?
How do we communicate using waves?
Why is a Tsunami so devastating?
How much warning do you get of an Earthquake?
How do we know what the world is made of?
How do percussion instruments work?
How do string instruments work?
How do wind instruments work?
How can two light rays meet and produce darkness?
How is a rainbow formed?
How can we cook using waves?
What causes a sonic boom?
How does an X-Ray scanner work?
How do Ultrasound scans work?
How do microphones record sound and how do loudspeakers produce sound?
I'm short sighted, what's wrong and how do I see?
How do bats and dolphins sense their surroundings?
How do cameras work?
How does radar and sonar work?
Why do race cars go neeeeeeee-aaaawwwwmmmmm?
The Universe is expanding, but how do we know?