Aim: – To investigate how increasing the voltage can affect the flow of current
Prediction: – I predict that the higher the voltage the higher the current. If we feed more energy to the coulombs they will push the current around the circuit faster. In order to arrive at this prediction I used the watering can analogy to help me. I.e. I am walking around my garden with a watering can full of water in my hand and the plants I wish to water are at the end of my garden. I represent the Voltage. The watering can represents the coulombs and the water represents the current. I (the voltage) am carrying/pushing the watering can (coulombs) around the garden (circuit). As I am carrying/pushing the watering can (coulombs) around I am pushing the water (the current) around. The faster I walk (the higher the voltage) the quicker the water gets to the plants (the faster/higher the current is).
Method: – In order to carry out this investigation I am going to construct a simple circuit in which there will be a voltmeter allowing me to vary the voltage, and an ammeter allowing me to measure and record the current. I will start the voltage at 0V and will increase the voltage in steps of 0.5V, i.e. 0V, 0.5V, 1V etc. At each stage I will record the current alongside the corresponding voltage. I will repeat this experiment three times then will find the average of the results. In order to make this a fair test I will keep the thickness of the wire, the length of the wire, and the wire material the same throughout each of the three experiments.
Apparatus: – Ammeter, voltmeter, battery, wires and conducting material.
Average Current (A) rounded to 2dp’s
Conclusion: – I have found that my hypothesis was correct. When I increased the voltage the current also increased. My graph shows this clearly and as there are no anomalies my line of best-fit runs close to each point on the graph. Using my graph and results I have found there was a pattern occurring. The current increase was proportional to the voltage increase i.e. the current doubled when the voltage doubled.
E.g. 1V = 0.45A, 2V = 0.90A 1V x 2 = 2V 0.45A x 2 = 0.90A
This shows Ohm’s law applied to this investigation.
In this particular experiment the wire was used as the resistor. As it was a thin wire it had high resistance. Although when the voltage got higher I noticed the wire got hotter so the resistance may have changed a little.
Evaluation: – I was very pleased with my results as they showed I had conducted the experiment successfully and allowed me to analyse them in detail and therefore arrive at my conclusion. As previously mentioned there were no anomalies so this suggested quality results. I found the procedure involved to arrive at such reliable results was simple. The only adjustments I would consider making would be to have monitored the length of time the circuit was connected up as I found the wires became hot and therefore a hazard. I would also have repeated the experiment more times as I would have been interested to know if the Ohm law applied throughout my results.