Visual arts are a great way to introduce or illustrate just about any topic in school.
When you have to represent a whale using some Bristol paper and paint, you are naturally motivated to learn what they look like. And from there, curiosity will lead to further discoveries.
This is an easy and inexpensive craft activity that can help make kids more aware of the fact that many whale species are endangered and that if nothing is done to protect them, they may become extinct. It's a perfect fit for Earth Day.
I have worked with a school who organized a "whale parade" where each kid carried their whale on their head (like a hat). Each whale was different and it was a lot of fun!