Creating Graphics for Interaction

I have created a series of graphics that I am using in my iBook, and they are all of a similar style.

These are all and will be featured throughout my entire iBook, and a lot of them as part of 'Pop- overs'. A pop over is when you click on an image and then a text box appears above it containing information. I have found these particularly useful as they allow me to bring the text off of the main page and feature in the necessary areas, but not so that it's overwhelming, which a large paragraph of text can be to teenagers. 

Using Pop Overs on the Volcanic Gases page has allowed me to completely remove any text from the page and apply a simple but attractive 6 square grid of these sorts of graphics. 

I've applied the same technique here. I drew out the 4 stages of a typical volcano being formed, removed the majority of the text on the page and allowed the user to 'discover' more information via clicking on the graphic. There is a text box at the top of the page instructing the user to do so. By focusing the users initial attention solely on the graphics, it engages them more and is less likely to put them up. Some will understand the point purely from looking at the graphics, and some will explore for more information. In a way, it makes additional information optional.