Use the circuit shown.
Turn the potentiometer P1, until a voltage of approx. Vin = 0.68 V applies to the base. At the same time you measure at the output a typical value of approx. Vout = 2.50 V.
Turn P1 a little further until a voltage of approx. Vin = 0.69 V applies to the base. Now you measure a typical value of approx. Vout = 1,75 V at the output.
A change of only 0.01 V at base results in a fall of 0.75 V at the output (inverting!).
The values can vary greatly in your experiments. Important however is the finding...
The voltage gain of a common emitter circuit is high.
Since both current and voltage is amplified, another finding can also be stated...
The power gain of a common emitter circuit is high.
Now you compare these results to a common collector circuit...?