Plan:
I plan to find out in the experiment how the length of bare resistance wire effects the resistance while doing the experiment. To do this I plan to set up a circuit as shown in my diagram and then adjust the resistance wire to different lengths to see if the results are effected by this. I plan to keep the voltage on the power pack the same throughout the experiment I am planning to use 6 different resistance wire measurements they are going to be 150cm, 160cm, 170cm, 180cm, 190cm and 200cm. In the experiment I am going to measure how resistance effects the voltage(V), the current(Amps) and also I am going to measure the resistance under each resistance wire measurement. The factors that could effect the experiment are there could be trends in the results, I may not record the results correct on my graph. I could set the amp meter or voltmeter to the wrong setting which could make my results inaccurate. I think that the less resistance wire used, the easier and quicker the current will be able to flow through the circuit. To make my planning easier I have done work even before I wrote this assessment, I have found out that resistance is a measure of how hard it is to get a current through a component at a particular potential difference or voltage, I learnt this from the AQA Double Award Modular Science- The Tested Modules (Higher Tier Book). Also I found out that
Potential Difference(volt, V) = Current (ampere, A) x Resistance (ohms)
Is the way to work out how current and resistance are related.
Fair Test:
To make sure the test is fair I will keep the voltage on the power pack the same throughout the experiment. Also I will make sure the readings on the voltmeter and amp meter are always recorded how each metre says and not change them to make the results more accurate. I will use the same apparatus throughout the experiment. I will make sure each wire is connected up correctly before doing the experiment.
Safety
I will make sure I am safe through out the experiment by not touching any of the apparatus if I have wet hands. Also I will make sure that non of the wires are tangled up or in the sink. I will also not mess around with the apparatus. To make the experiment even safer I could wear rubber gloves on my hands, this would be good because rubber is a good insulator.
Method
First of all I got the equipment I would need to do the experiment, I needed:
- 1 Amp Meter
- 1 Voltmeter
- 1 Power Pack
- 1 One Meter Ruler
- 1 Crocodile Clip
- Ordinary 4cm Connecting Lead
- Bare Resistance Wire
I set the apparatus up a shown in my diagram of apparatus. I set the power pack to 6 volts, throughout the experiment the power would never be changed. I set the amp meter and voltmeter to the setting we were told to set it at. I made sure that the reading on the amp meter never went over 3 amps throughout the experiment for safety reasons. I measured the resistance wire to the 200 cm and used a crocodile clip to connect it to the meter ruler. I then turned the power pack on and recorded the readings on the amp meter and voltmeter as shown in my tables of results. I repeated the experiment for the other resistance wire measurements. I did each measurement twice to make my results more accurate. To work out the average for each length of resistance wire I took both sets of results and first looked at the 200cm results I used both them and did this formula to work out the resistance:
R= V divided by C
I then repeated the formula to work out the other results. I then recorded the averages on my table.
Tables Of Results
Diagram Of Apparatus
