Fishbowl

Four to five chairs are arranged in an inner circle. This is the fishbowl. The remaining chairs are arranged in concentric circles outside the fishbowl. A few participants are selected to fill the fishbowl, while the rest of the group sit on the chairs outside the fishbowl. In an open fishbowl, one chair is left empty. In a closed fishbowl, all chairs are filled. The teacher introduces the topic and the participants start discussing the topic. The rest of the class outside the fishbowl listen in on the discussion.
In an open fishbowl, any member of the class can, at any time, occupy the empty chair and join the fishbowl. When this happens, an existing member of the fishbowl must voluntarily leave the fishbowl and free a chair. The discussion continues with participants frequently entering and leaving the fishbowl. Depending on how large your class is you can have each class member spend some time in the fishbowl and take part in the discussion. When time runs out, the fishbowl is closed and the discussion is summarised.
In a closed fishbowl, the initial participants speak for some time. When time runs out, they leave the fishbowl and a new group from the class enters the fishbowl. This continues until all the class members have spent some time in the fishbowl. When time runs out, the fishbowl is closed and the discussion is summarised.