A breadboard is a grid of sockets for developing electronic circuits and microcontroller projects, composed of conductive strips beneath the nonconductive cover. Because it is solderless, it's useful in prototyping, but more susceptible to falling apart when handled roughly.

The main grid, which is 10 columns wide and labelled a through j, has connections across every row, connecting a through e of every row, and f through j of every row. The small boards held in the physical computing lab only have these connections, and not the bracketing columns commonly found in other breadboards.

The small breadboard in particular is used when you need to make a very limited number of connections. Maybe you just don't need to connect a whole lot of parts, or you are constructing a project whose dimensional constraints demand that you use small breadboards placed at various important locations. Either way, the small breadboard is a versatile tool for making small sets of solderless connections.