I predict that my graph will be curved because this is based on two theories. First the temperature will not be constant. Secondly the resistant of the filament lamp will not be constant. If the voltage was to be increased the graph would be come more curved and the gradient will be positive and it will be steeper. There will a relationship between the amps and the volts.
I predict that the line for the graph of the resistor. I predict this because no heat at all is given off, therefore it will not affect the resistor. Heat is not give out by the resistor however like the filament lamp does give out heat. I predict that there will a relationship between the volts and amps. This is because the resistor is going to be constant. I also predict that my graph will have a positive gradient, which means that there will a constant in temperature.
Variables: For this experiment I would expect to have 3 different variables, Independent, Dependent, and fixed variables, which all helps me to plan and explain the experiment thoroughly.
Independent variable (which you can change): The thing that I will change in this experiment is the voltage from the power supply. This affects the filament and the resistor. By changing the voltage to see the different results for the volts and amps. The ranges I will be using are from 2 – 12 voltage.
Dependent Variable (objects/items that you measure): The thing that I will be measuring is the volts and the amps as I change the voltage from the power supply.
Fixed Variables (objects/items that will remain the same): the thing that I will be keeping the same to keep it a fair test is the equipment. By keeping the equipment the same it will able me to gain the best results.
Safety: Throughout your experiment safety was our main concern at all times. If the equipment was not to work and we would get a small electric. This could be dangerous.
Method: The following plan shows a step by step, what we did to achieve our results, in a fair way.
- Step 1: Collect all the equipment and set up the equipment as show in the diagram
- Step 2: Draw a results table, that u can input your data.
- Step 3: Use the range 2 – 12 for both of the resistant and the filament lamp from the power supply.
- Step 4: Then use the same ammeter and voltmeter to record the readings on the ammeter and voltmeter in amps and volts.
- Step 5: Write your results on to the results table to 2 decimal places for the amps and volts.
- Step 6: Repeat this experiment again about 2 to 3 times to get average readings. This is to calculate the average amps and volts.
- Step 7: Plot and draw a graph to check if there is an anomaly results.
- Step 8: Then calculate the resistance.
Analysis: My results show that I was right in my prediction. This was because I predicted that for the filament lamp, as the voltage increases so will the resistance. This was because of the light and heat coming from the filament lamp. This happens when the temperature increases. The filament lamp produced a lot of heat because of the electric current passing through the lamp. The particles start to vibrate as the temperature in the filament lamp. This made it difficult for the electrons to pass through.
My prediction for the curved graph was correct. This was because this was based on two theories. The temperature will not be constant and the resistant of the filament lamp will not be constant. The graph showed a positive gradient, as I predicted in my prediction. At the beginning of the curve there was a low resistance when the gradient was small. Once the volts where increased the gradient also increased. The more voltage that was applied and increased the gradient would tend to steep. I also predicted that as the amps and volts increases so will the resistance this was also correct.
My prediction was correct for the line of resistance, this was right. This was because of no heat given of by the resistor, due to the fact that the resistor was kept at a constant temperature. The heat was also has no affect on the resistor. Heat is not give out by the resistor however like the filament lamp does give out heat. There was a relationship between the amps and volts. Through out the readings the resistance was kept constant.
Evaluation: In my opinion the experiment went well. I gained a good set of results and altogether I am pleased with the investigation. The aim of the investigation was to find electrical behaviour of a resistor and a filament lamp. I did this productively. There is a strong pattern for the results I took down, which I then plotted to form a graph.
The experiment was easy to set up and to do, but all results had to be recorded accurately. In-order to gain a fair test. The most difficult part of the whole experiment was to record my results down. This was because the readings from the ammeter and voltmeter kept on going up and down. This maid it hard to read of the results from the ammeter and voltmeter. This could have affected my overall results. The other difficulties I had were to record my results from the voltmeter and ammeter into amps and volts.
If I were to repeat the same experiment again I would try and ensure that I would find a better way to read of from the ammeter and voltmeter. In-order to have the best accurate results ad to do this in a fair way.
References:
Modular Science for AQA (2001)
Science Revision Book AQA
Kamal Dodia 11R Sciences Physics -
