Investigating Resistance of a Wire
The aim of this experiment is to find out how the resistance changes
as the length of wire changes within the circuit changes. At the end
of this investigation I will come to one of five possible conclusions
which are:
-the resistance increases as the length of wire increases, or
-the resistance decreases as the length of wire increases, or
-the resistance is constant as the length of wire changes, or
-the resistance increases as the length of wire decreases, or
-the resistance decreases as the length of wire decreases.
Scientific background:
Electricity is simply the flow of electrons, a cell produces
electricity. Lots of cells joined together form a battery. A battery
pushes electrons round a circuit from the negative terminal to the
positive terminal.
The voltage of a battery is a measure of the energy delivered by the
electrons to the lamp. The unit of voltage is the volt. Voltage is
sometimes called potential difference. Current is measured using an
ammeter. An ammeter must always be connected in series with the
appliance taking the current to be measured.
Resistance is what links current and voltage together. Resistance is
the property of a substance which opposes the flow of current is
called its resistance. A substance which possesses low resistance is
said to be a good conductor of electricity; poor conductors are those
which posses high resistance. In 1827, George Simon Ohm, a German
scientist discovered the relationship between the potential difference
(voltage) applied between the ends of a conductor and the current
passing through it. This important relationship is now known as ‘Ohms
law’ which can be stated as follows:
‘The current passing through a conductor is directly proportional to
the potential difference applied across its ends, provided that the
temperature and other physical factors of the conductor are kept
constant.’
The resistance of a wire is directly proportional to its length and
inversely proportional to its cross-sectional areas.
As said in ohms law, resistance also depends on the physical factors
Metals contain a sea of electrons (which are negatively charged) and which flow throughout the metal. This is what allows electric current to flow so well in all metals. An electrode is a component of an electric circuit that connects the wiring of the circuit to a gas or electrolyte. A compound that conducts in a solution is called an electrolyte. The electrically positive electrode is called the anode and the negative electrode the cathode.
From this I can tell I can use 3 volts and resistance wire that is
equation V = IR. V - volts, I - current and R - resistance. I plotted
The Resistance of a Wire Investigation Aim: To investigate how changing the length of a wire affects the resistance. Prediction: I predict that the longer the piece of wire, the greater the resistance will be. This is because the current is resisted by the atoms in the wire. In a longer piece of wire, there would be more atoms for the electrons to collide with and so the resistance would be greater. The shorter piece of wire will have less resistance because their will be less particles causing less collision.
I also decided to use a wooden block to keep hold of the wire, because
A battery is a device which converts chemical energy into electrical energy. A battery usually consists of two or more cells connected in series or parallel, you can also have a single cell battery. All cells consist of a positive electrode, and a negative electrode. An electrolyte is a liquid substance capable of conducting electricity. In this substance one of the electrodes will react producing electrons, while the other will except electrons. When the electrodes are connected to a device to be powered, called a load, an electrical current flows.
Investigating the Effect the Thickness of a Wire has on Its Resistance. Equipment:.. Nickel Wire cut into 10 pieces of 30cm length (Ruler, Pliers). Two crocodile clips Five Pieces of Wire Power Source Variable Resistor Ammeter Volt Meter Method: The.. =
This is know as resistivity. The factors I can investigate are : Ÿ Temperature Ÿ Length Ÿ Cross-sectional area/width Ÿ Material (resistivity) The factor I shall investigate is the length of a wire. Background Knowledge Resistance is when electrons travelling through the wire are impeded by the atoms within the wire. Since the electrons are charge carriers when they collide with the atoms in the wire less pass through.
The invention and development of the battery would have to be one of the most significant in human history. Without batteries, the world would be a very different place. Everything would be plugged in and nothing would be mobile. There are many types of batteries that work in many different ways, but they all have the same common goal of making lives easier. Some examples of these batteries are lithium-ion, lead-acid, and nickel-cadmium.
The Relationship Between Length, Width and Resistance of a Wire Aim: To investigate how the length and width of a wire affects the resistance of the wires. What is the resistance to a s Electricity is conducted through a conductor, in this case wire, by means of free electrons. The number of free electrons depends on the material and more free electrons means a better conductor, i.e. gold has less resistance to the sand. For example, gold has more free electrons than. iron and, as a result, it is a better conductor.
You take voltage measurements by counting the number of divisions a waveform spans on the oscilloscope's vertical scale. Adjusting the signal to cover most of the screen vertically, then taking the measurement along the centre vertical graticule line having the smaller divisions makes for the best voltage measurements. The more screen area you use, the more accurately you can read from the screen.
First off, what is current. Current is expressed in a unit called Amps. Amps are a measurement of how many electrons pass per second. That is to say, a wire with 40 coulombs passing any point in a 2 seconds would be said to have 20 Amps of current (40 Coulombs (a unit of charge given as 6.24x1018 electrons) / time in seconds or in this case, 2 seconds. The Amp is also known as Coulombs per second) Another trick about current is that it is measured in the movement of the positive charge. Literally that is to say the current moves in oppostion to the electrons. This is because originally it was thought that the positive charge is what moved, both are viable, but in reality a positive charge is generally fixed since within an atom the electrons are migratory, while the protons and neutrons tend to be stationary.
V(voltage) I (current) Therefore, I = V R Therefore, if V is constant, in order to increase I, R must decrease.
Direct current only flows in one direction in a circuit. Because the polarity of a direct current voltage source is always the same the flow of current never changes direction. Batteries are one of the more common direct current voltage sources. Batteries are good because their voltage is fixed as well as their polarity. Direct current dose not always need to a constant voltage but it must always stay traveling in the same direction. There are such direct currents called varying and pulsating that change value but not direction.
Ohm’s Law is also subject to a specific amount of pressure on the substance. For example placing a conductor under tension (a form of strain), causes the length of the section of conductor under tension to increase causing the cross-sectional area to decrease, hence changing the value of resistivity and conductivity.