Aim: My aim is to find out by changing the depth of the copper changes the current.
These are the variable that I could have changed:
- Time
- Current
- Temperature
- Concentration of solution
- Quantity of solution
- Size Of electrodes
- Distance between the electrode
- The surface of the electrode
- Depth of the copper in solution
The variable I will be changing is the depth of the copper in the solution. The experiment carried out aimed to monitor if by changing the depth the Copper (Cu) metal in the Copper Sulphate solution (CuSo4) affected the current. Whilst at the same keeping all the above variables at a constant level making the test accurate to find out my aim.
I predict that having the copper in the solution will make the current higher when the depth is greater. I think this because more area of copper is exposed to the solution. At 1cm it there is less copper actually in the solution therefore less current is needed. When 5cm of copper is in the solution a higher current is needed to get the same effect. If more of the copper touches the solution the more it can react, therefore increasing current.
Apparatus list:
- Copper
- Cylinder 100cm
- Beaker
- Copper Sulphate Solution 100ml
- Voltmeter
- Wires: Cathode and Anode
- Power Pack
Method:
After collecting all the apparatus and setting up the voltmeter etc I measured the copper sulphate solution and made sure the wires were attached to the correct ends. Anode being the positive end and Cathode the negative. I need to mark the centimetres onto the copper so I can change the depth accurately I will mark centimetres from 1-5 because hey are the depths I am looking carefully at. After every depth I need to take down the current. After I have completed my experiment for accuracy I will repeat it two more times then work out the average.
Safety Precautions:
* Electricity is dangerous therefore be careful while connecting the apparatus always check if the power supply is turned off.
* Too much electricity is also dangerous because it might cause the equipment to work over load causing it to break. May be the circuit wire might melts causing fires.
* Always wear safety glass because something might happen to cause you to go blind e.g. the solution could gets vigorous and might "pop" out of the beaker and goes into your eyes.
Conclusion:
I conclude that my results do support my prediction to some extent. By looking at my results I’ve noticed the current is increasing with the depth although by looking at my graph it seems to flatten near the end. Without looking closely this could be seen as a line of best fit but when using a rule to check I noticed it isn’t a line of best fit. To find out if this is defiantly happening I could extent my experiment trying more depths to see if the current is actually increasing with the depth. I have found out that it looks as if the current is increasing with the depth but I still have doubt in my mind so it would be useful to repeat my experiment trying more depths. Without a graph I would have thought these results were accurate because the numbers do show the current is increasing with the depth. The graph has shown to be very useful as it makes it more obvious that maybe the current isn’t increasing. I can now see that my graph is sloping, I don’t know how accurate my experiment is. I didn’t predict this happening I expected a line of best fit showing the current is defiantly increasing with the depth. My primary results show a line of best fit therefore I need to consider why I didn’t get a line of best fit.
Evaluation:
Although this was a successful experiment, there were some factors of the experiment, which could have been improved to make it even more successful. One of these factors could have been the copper, which, even after a good clean were still quite dirty and obviously still had irremovable substances from previous experiments still attached to them. If this experiment were to be repeated for a second time, in need of greater accuracy, it would be imperative to have a new piece of copper, which have never been used before.
Another factor is that my graph leaves some doubt in my mind if the current is actually increasing or maybe I need to look back and see if my experiment was totally fair. As I said in my conclusion the graph doesn’t have an exact line of best fit. It seems to curve near the end. If I was to repeat my experiment I would try more depths and see if my graph fattens more or if there is just a fault in my results. Apart from this I can’t see any reason to why my experiment wasn’t accurate.
