Insert 8 D flip-flops in an electronic breadboard. Wire the voltage supply pins of each flip flop to the voltage bus of the breadboard. Wire the ground pins of each flip-flop to the ground bus of the breadboard. Wire the positive terminal of a 5-volt power supply to the breadboard's voltage bus and the negative (ground) terminal of the power supply to the breadboard's ground bus.
Insert 8 electromechanical switches into the breadboard (one for each flip-flop). Wire the first flip-flop such that its D (data input) will be connected to either the voltage bus or the ground bus (depending on whether the switch is turned on or off). Wire the remaining 7 flip-flops in the same way such that there will be one switch that will control the input voltage level to just one flip-flop.
Wire the clock inputs of the D flip-flops together. Insert a metal pin into the breadboard peg hole that is connected to this common clock line (so that the clocks can be easily pulsed with a wired battery connection to the voltage bus).
Set the switches such that all the D inputs of the flip-flops will be connected to the 5-volt voltage bus. Temporarily wire the 5-volt voltage bus to the common "clock" input of the D flip-flops. Remove the wire and measure the voltage at the Q output pin of each flip-flop. Note that the voltage levels at the Q outputs will all be 5 volts, indicating that the data presented at the D inputs (when the clock line was pulsed) have been stored in the flip-flops.
Set the switch settings such that the D inputs of all the flip-flops will be connected to the ground bus (0 volts). Temporarily connect the ground bus to the clock line. Remove the wire and measure the voltage at the Q output pin of each flip-flop. Note that the voltage levels at the Q outputs will all be 0 volts, indicating that the data presented at the D inputs (when the clock line was pulsed) have again been stored in the flip-flops.