I have heard of teachers doing a Wonder Wednesday and I like this idea of doing it once a week so that you can be selective in the wonders you choose - there is a huge archive. You would be unlucky not to find one that matches your current topic. I think one idea would be for students to have a go at answering the 'Wonder' in their writing. They could also use research skills (under supervision) on iPads, of course, to find the answers. As a class you can then look at the resources on Wonderopolis that give the answer.
You may be wondering why I am posting about this website on my iPad Blog or you may have guessed - it is also an app. The app has most but not all of the same features as the website.
Just to inspire you even more, here are some recent wonders:
Why Do Stink Bugs Stink?
Why Do Dogs Have Wet Noses?
How Does a Thermos Work?
Why Do Mosquito Bites Itch?
Where is the Biggest Castle in the World?