Voltage and current are proportional, and the constant of proportionality is the resistance.
Most physics comes down to a straight line graph through the origin. And this is no difference.
It's going to be important for you to know this experiment by heart and to know and use the equation that we get from it. It's one of the most important parts of your toolbox for solving electricity problems!
potential difference (V) = current (A) × resistance (Ω)