Educational psychology findings indicate that active processing (such as self-testing) is more effective for learning than passive reading or even rereading. Electronic books (ebooks) can include much more than static pictures and text. Ebooks can promote better learning by increasing the reader's interaction with the material through multi-modal learning supports, worked examples, and low cognitive load practice activities. For example, multiple choice questions with immediate feedback can help identify misconceptions and gaps in knowledge. Parsons problems, which are mixed up code segments that have to be put in the correct order, require learners to think about the order of the statements in a solution without having to worry about syntax errors. Our research group has been applying concepts from educational psychology to make learning from ebooks more effective and efficient. This paper reports on an observational study and log file analysis on the use of an ebook that incorporates interactive activities. We provide evidence that learners engaged in the interactive activities, but used some types of activities more than others. We also found evidence that learners encountered some "desirable difficulties" which can improve learning. This descriptive study informs a research agenda to improve the quality of instruction in computing education.