Like any device the storage on the iPad can become full. This can cause it to become slow, non-responsive touch screen, 'glitchy' behavior, and can even lead to loss of school work.
To resolve the situation go to General > Storage & iCloud Usage > Manage Storage. This will show you what is taking up the most space on your iPad and what you can likely delete to help the situation. The usual suspects are photos, games, videos and music.
Important Note: There are some Apps like iMovie that utilize photos and videos in the camera roll. So please be careful in what you delete as it can affect other work. Also be sure you have a backup of your iPad before deleting anything.
Finally, restrictions may be placed on iPads if students have been notified multiple times that they need to clear up space and failed to do so.
For questions contact Tech Help @ SMA.