When you aren't online, you can still do lots of things with your Chromebook.
The Chromebook and its corresponding OS have the ability to work in both online and offline modes. Students who do not have access to a wireless network outside of school do not need to panic. They will be able to continue working on their device and sync their newly added data to their accounts once they have accessibility to a wireless network.
When students are connected to a wireless network they will be able to fully utilize every aspect of Google Apps for Education along with the Chrome Web Store apps provided to them through the GPS domain. In offline mode students can still create and edit Google Documents, Drawings and Presentations. Google Spreadsheets, Microsoft Office Files, images and PDFs will be available to students in view only mode.
Some third party apps located within the domain, made available to students, do have offline capability.
Nevertheless, as mentioned earlier, once students "hit" a wireless network, their work in offline mode will sync to their account and become available with the latest updates in their Google Drive.
To learn more about Google Drive's offline capabilities for non-Chromebook devices visit Google's Offline support page.