Google has recently integrated Google+ into Google Apps for Education so you can now make use of the special Google+ features such as hangouts. A hangout is a video/audio chat tool that can support up to 10 users simultaneously. Here is a quick way you can start a hangout:

• Click on the + icon in the top-left of your Google Apps menu (you will need to join Google+ if you haven't already) click the Start a Hangout button on the top right side of your screen.