Results
Conclusion
The graph is showing a straight line through the origin. This means that as the voltage increases, the current also increases uniformly.
A graph of Voltage and Current for a resistor was the same, when I did the experiment. This means that the liquid behaves like a resistor. Which was what we were trying to find out.
In a liquid, a current is the movement of ions. In Copper Sulphate (CuSO ) solution the sulphate ions are negative and move to the anode, the copper ions are positive and move to the cathode. The anode is the positive plate and the cathode is the negative plate.
If you increase the voltage then the plates become more charged and the ions move around faster, so the current increases.
Evaluation
We were trying to make the investigation as fair as possible, this was hard because it was difficult to keep the copper sulphate solution at the same temperature throughout the experiment. Keeping the two plates, cathode and anode, in the same place and depth inside the copper sulphate solution was also difficult.
Trying to make accurate measurements was also difficult. This was because the meters were not accurate; they kept on changing the readings. Therefore we had to choose the reading that appeared the most. It is quite likely that the equipment we used were recording a true measure.
It was important to carry out repeat readings because of the changing temperature of the copper sulphate solution, the moving plates and the accuracy of the readings. We took enough readings to get a reasonably reliable answer. If we had wanted even more accurate answers then we could have performed more measurements.
We could of collected more evidence towards the resistance of a liquid by doing more background work and further work. Some further work would have been trying to find out the outcome of the tests if we increased the voltage going into the circuit. We could have tried different solutions, e.g. Salt Water. We could also have tried the solution at different strengths, weak or strong, e.g. 0.5M.