Introduction Planning – Aims, Variables, Fair Test, Prediction, Hypothesis Planning – Apparatus, Procedure Planning -Procedure of temperature, measurement, safe rules Obtaining Analyse – Table 1 Analyse – Table 2 Analyse – Table 3 Analyse – Table 4 Analyse – Table 5 Analyse – Table 6 Analyse – Table 7 Analyse – Table 8 Analyse – Compare and Contrast Evaluation, Conclusion, Bibliography Introduction: What is an electrical circuit? An electrical network is an interconnection of electrical elements such as the resistors, inductors and switches.
We use circuit to measure the voltage, and also the current of some conductors which can transfer the electricity. To design an electrical circuit, first we need to be able to predict the current and the voltage. What is electrical resistance? Electrical resistance is a measure of the voltage divided by the current flows in the electrical circuit. The unit of resistance Is Ohms,?. The quantity of resistance in an electric circuit determines the amount of current flowing in the circuit for any given voltage applied to the circuit. The way of measuring the resistance in a circuit is: “R” is the resistance of the object, measured in ohms.
“V” is the potential difference or the voltage across the object, measured in volts. “I” is the current passing through the object, measured in amps So what are the uses of electrical circuit? This is a test to find out the best conductor in metals, the higher the resistance, that means the better the metal could be used to pass the electrons through. Also, the temperature of the metal will affect the amount of electrons flows at each time, by heating the metal up, it would expand and allows more resistance; so the temperature were low, it might can’t conduct electricity at all. Planning: Aims:
In this experiment, I will try to prove the thicker the wire; the more the resistance, there would be and also the more current flowing flows per second. And also to prove that “Copper” wire will have the highest current flow by time each second. Variables: 1. The low-voltage wires used in the experiment. 2. The low-voltage power supply used. 3. The materials of the wires used. Control Variables: 1. The diameter of the wire used in the experiment. 2. The length of the wire should be measure before the experiment. 3. The temperature of the wire from room temperature to 80i?? C. 4. The amount of charge flows in the circuit. Fair Test:
In this experiment, I would first make sure that the ammeter and the voltmeter were perfectly set, if we did not set it well, this will affect our results of resistance. Also I have to make sure all the crocodile clips I used have the same materials, or else the flow of charge would be different. The diameter of the wires should be equal, this is going to keep the flowing charge remained to be the same. The switch must be working well, or else we can’t switch it on, that means we can’t start the experiment well. The light bulb better is working as well, or else there might be some problems getting the results of the resistance out.
Repeat the experiment for two more times to check the results. Prediction: By setting everything well, I predicted that by using a diameter of 1. 25mm wires will have the highest amount of resistance compare to the diameter of 0. 45mm wires, this is because that it can allow the greatest flow of charge to pass through. The materials of the wires could be affecting the experiment, as we used the wires of copper, the results should be better than using constantan because they allows more current to pass through in time, therefore can transfer more energy. Hypothesis:
It is likely to be seen that because the greater of diameter, the more the charge could be flow by time, there were larger space to allow charge to pass through. According to Encyclopedia website, I have discovered that a copper wire is easier to be used for experiment, because of its reactivity series, it will have a least resistance compare to the Nichrome and Constantan wire. Method: Apparatus: Safety goggles Ammeter Voltmeter Switch Variable resistor Bulb Wires of copper with crocodile clip Power Supply Constantan wire with 0. 45mm diameter, 0. 9mm diameter, 1. 25mm diameter.
Copper wire with 0. 9mm diameter Nichrome wire with 0. 9mm diameter Procedure: 1. Prepared all the apparatus that needed. “Change Symbol I to A” 2. Connect the switch with the power supply with a wires 3. Connect the other side of switch with the variable resistor by using another wire. 4. Set the ammeter on the other side of the constantan wire. 5. Set Voltmeter parallel to the constantan wire. 6. Check the circuit is built well. 7. Switch the power supply to a voltage of 4V. 8. Move the resistor to protect the ammeter, and keep it fixed. 9. Turn the switch on and record down the voltage and the amp down.
10. Calculate the resistances by using potential difference (in V) divide by current (in A). 11. Plot a graph to show the results. 12. Repeat the experiment for 2 more times to check the results. 13. Re use this method with the rest of the constantan wires and copper, nichrome wires. Procedure of temperature: 1. By raising the temperature, copper wire should be used. 2. Follow the method above until step 8. 3. Put the water with room temperature into a beaker. 4. Put the wire into the water. 5. Switch the power supply on and record down the voltage and current for three times. 6.
Add boiling water at 80i?? C and put the wire in. Record the voltage and current down for another three times. 7. Wait until 50i?? C and record anther result down. 8. Plot a graph to see the differences between this experiments and the rest. 9. Calculate the resistance using voltage divide by current. Measurement: In the experiment we have to make sure the batteries were new, so hopefully it would have the same amount electrons. So the flow of charge won’t be a different from the results. By checking we use the Power Supply, it can be very accurate of given out charges into a circuit.