This represents that when the wire was a shorter length it was easier for the electrical current to flow through it as it was less resisted. This happens because as the metal gets warmer, the metal ions in the wire gain kinetic energy and start to vibrate. If say 5 electrons try to pass through those two wires, the chances of them bumping into atoms are higher in the 20cm wire than the 10cm one. What is the resistance of the electromagnet? An electron traveling through the wires and loads of the external circuit encounters resistance. Results Why do we get resistance? A thin wire has fewer electrons to carry the current than a thick wire.
Electrons colliding with the positive ions, causing the electrons to slow as their kinetic energy has been transferred to the positive ions, cause resistance. The more collisions there are, the more difficult it is for the electrons to pass through and therefore the greater the resistance. In addition, the wavelength can change the rate of photosynthesis. Note the reading on the ammeter. In a thin wire these electrons have to constrict tightly together in order to pass through, however in a thick wire these electrons do not have to constrict together as much to be able to pass through. In this investigation, we are investigating how the length of wire affects resistance current and voltage.
The resistance of a wire depends on the number of collisions the electrons have with the atoms of the material, so if there is a larger number of atoms there will be a larger number of collisions that will increase the resistance of the wire. The automotive industry Requirement to measure the resistance of robot welding cables to ensure that the weld quality does not deteriorate, i. Demonstrating that as the resistance increases the thickness did, this is the second factor which affects resistance. For instance a 10cm wire has 5 atoms, a 20cm wire has 10 atoms. For most but not all materials, resistivity increases with increasing temperature.
It can be beneficial, as in electric heaters, or a pest, as in light bulbs, where the heat is produced alongside the light — we want maximum light and minimum heat. However my results were reliable, this is evident as I conducted the test twice enabling me to produce a comparison of result. Its value depends on four things. Next, move the crocodile clips down five centimetres rather than ten as done in preliminary each time to record the results. Plot a graph of these readings. The investigation has concluded that there is a clear relationship between the length and the resistance of a wire, and that the former does in fact affect the latter.
The ammeters and voltmeters could have been damaged and reading falsely on both the meters used. It should be noted that the meter measures the voltage at its terminals and not across the component. Resistance of leads too high Whilst in theory the four terminal method of measurement is unaffected by lead length, care must be taken to ensure that the leads are not too high in resistance. There are possible sources of error that might have led to inconsistent results, such as a kink in the wire. To collect the data for my graph I have chosen to take a range 20 of lengths. The meter then calculates and displays the resulting resistance and is known as a twowire measurement. They employ the 2 wire method of measurement and are only suitable for measuring values above 100Ω and where high accuracy is not required.
If you use a mains power supply, use one that is designed to limit the output current to about 1 amp, and preferably with a current overload indicator. Another aspect from the mathematical function that can be identified is the Y intercept which was 2. This is clear as the wire extends 10cm the resistance enlarges. To record the difference in widths I would use the same voltage and measure the resistance for each thickness. Wire temperature °C Voltage Volt Current Ampere Resistance ohm 25 4. Plot a graph of your results; this graph is known as the voltage-current characteristic of the lamp. This method of measurement will produce accurate and consistent results when measuring resistances below 100Ω.
There is, however, a scientific explanation behind all this. A longer wire also means that it would have more atoms, which means it will be more likely for moving electrons to collide with them; hence, higher resistance. The Elodea produced more bubbles with sheets at each end of the spectrum because the chlorophyll in the plant absorbs all the colours but transmits green. To provide extra evidence, more repeats could have been done, and an extra experiment on different types of wires, seeing how the material affects resistance. Use the E26 wire as it will also be easier to measure any change in resistance. Mostly the experiment was a success. Resistance is a measure of how hard it is to move the electrons through the wire.
Results for second test Voltage used 6V Thickness used 34wsg Length cm Voltage v Current A Resistance ohms 10cm 4. Ensuring Accuracy To ensure accuracy I will record the voltage and the current three times every 5cm and take the average reading. Copper and aluminum are among the least expensive materials with suitable conducting ability to permit their use in wires of household circuits. Furthermore, if you double the length of the wire, the resistance is roughly doubled. The diameter of the wire will have an affect on the resistance of a wire. For this experiment, the independent variable is the temperature of the copper wire.
Starch does not dissolve in water very well so it makes a better food store. Measure out around 120cm of wire to stretch across the ruler so I have reasonable excess to attach my crocodile clips too. A Guide to Resistance Measurement With resistance measurement, precision is everything. We did not find anything, which stood out too much from the pattern except that the red plastic sheet, when used resulted more bubbles generally than the blue sheet. It should also be noted that some coatings and oxides on materials are good insulators. Do not try and adjust the circuit while the components are switched on. This wire has much more resistance.