Science Coursework
The Resistance of a Wire
Aim:
To find out how the length of a wire affects the resistance of it.
Knowledge:
Ohms Law is a mathematical equation that shows the relationship between Voltage, Current and Resistance in an electrical circuit. It is stated as:
, V = I x R
, R = V / I
, I = V / R
Where
· V = Voltage
· I = Current (I stands for INTENSITY)
· R = Resistance
In order to understand what Ohms Law is all about you need to understand electricity and what makes Voltage, Current and Resistance in a circuit.
Current
Current is the movement of electrons in a circuit but "What are electrons and what makes them move?"
All matter is made up of Atoms.
Piece of metal made up of Atoms
Each atom is made up of a nucleus that has a certain number of protons and neutrons with an equal numbers of electrons in orbit.
The copper atom has 29 protons in its nucleus with 29 electrons orbiting the nucleus. The electrons are arranged in orbits called shells.
Notice that in the copper atom, the outside shell has only one electron. The outer shell of any atom is called the valence shell. When the valence electron in any atom gains sufficient energy from some outside force, it can break away from the parent atom and become what is called a free electron.
It is very easy to provide enough energy to cause the valence electron to become free. Some sources of energy are heat, light, magnetic fields and a voltage source. When the valence electron becomes free it leaves behind an atom that has a positive charge. Remember that the copper atom has 29 + protons and 29 electrons so if one electron leaves orbit we are left with +29 protons and 28 electrons. That means the atom has a more positive charge because of the one less electron. This is an unbalanced atom and is not natural. The atom will always try to get an electron back into the valence orbit to become normal or balanced again.
This is the one fact that you should remember and try to visualize when working with electrical circuits.
Electric current is the movement of electrons from one atom to another in a conductor.
If you can visualize a piece of copper wire with billions of atoms and each one of them losing an electron and all the electrons jumping to other atoms, you will begin to see what current is.
Isotopes refer to 1 of 2 or more atoms with the same atomic number but different numbers of neutrons. The atom copper has two stable isotopes. They are 63Cu and 65Cu. 63Cu has an isotope atomic mass (in amu) of 62.9295989 and a natural abundance (in atom %) of 69.17. 65Cu has an isotope atomic mass (in amu) of 64.9277929 and a natural abundance (in atom %) of 30.83. The averag...
In the article,"Energy Story", it tells you all about basic energy and how scientists found out how it works. It tells you about each part of an electron and what part is what. The center is called the Nucleus. Electrons and atoms move together to create what is known as electricity. Atoms and electrons flow through an object
There are three main parts of an atom the electrons, protons and the neutrons. Each part has charge. It is rather positive, negative, or neutral. An electron always has a negative charge. Protons always have negative charges. Then finally the neutron is a neutral charge or a charge of zero. If the charge of the whole atom it zero that means there are an equal number of positive and negative pieces. An electron can be found anywhere around the nucleus, and the protons and neutrons are in the nucleus. You can not pin point were the electrons are but the area that it can be in is called a shell.
Do you ever wonder about what happens with electricity? In the article “Energy Story” written it tells you about atoms and what things need to have to be that type of object. In the article “Conducting Solutions” by Rodney Schreiner tells you about solutions and the reactions to them with electricity. In the video clip “Hands-on Science with Squishy Circuits” by AnnMarie Thomas it tells you about how simple play dough can hold electricity.
1) ABSTRACT: Relative motion between a magnetic field and a conductor are needed to create a voltage within the conductor. For current to flow the conductor must be a complete loop, if not the current will not flow.
Who said electricity doesn’t exist. Benjamin Franklin is the person who invented electricity by flying a kite in the rain with a key on it. So when he got it in the air, it started to lightning and thunder, so then this big bolt of lightning struck the kite and electrocuted him and that’s how he discovered electricity.
The element "Copper" also known as "Cu" in the Periodic Table has the atomic number 29 and has 29 protons, 25 neutrons, and 29 electrons. It belongs to the Transition Metal family and normally takes the phase of a solid. The element takes the color of red/orange and has a crystal structure which is cubic. The element also is a conductor used for electrical wiring in houses, computers, light bulbs, etc... It's atomic mass is 63.55 and has the ionic charge of 2+/+. Copper has a total of 6 isotopes 4 being unstable and 2 being unstable and 2 being stable. The 2 naturally stable isotopes of copper are -63 and -65. The isotopes are different from one another according to the mass number. The electrons inside of copper are distributed evenly excluding
A current is the flow of charge round a circuit, this can be in the
Merriam Webster defines Galvanism as “a direct current of electricity especially when produced by chemical action”. The term Galvanism is actually derived from
For a second, imagine yourself in a frozen cabin, with wet wood, oil and wax, trying for hours to make a fire in order to get light and heat in your room. This procedure ended in 1897, thanks to the American inventor Thomas Edison, who was finally able to produce a long-lasting light-bulb in his laboratory. Although it looks simple that turning on the lights just require to turn the switch on, the scientific theory behind it is quite complicated. Creating an electrical system requires a conversion from any sort of energy to electrical energy. For example, one of the first electrical energy sources was coal. Burning coal produces high temperatures that transfer into potential energy. Potential energy is then changed to electrical by the application of stress.
in devices such as inductors, electromagnets, transformers, and sensor coils. Either an electric current is passed through the wire of the coil to generate a magnetic field, or conversely an external time-varying magnetic field through the interior of the coil generates an EMF (voltage) in the conductor.
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.
Humans these days take electricity for granted. We don’t truly understand what life was like without it. Most young adults will tell you their life does not depend on electricity, but they aren’t fooling anyone. They all know that their life depends on electricity; whether it’s television, their phone, Google, or the lights in their house. We need to stop taking those things for granted and give credit where credit is due. That is why I chose to write about the scientists who contributed to the discovery of electricity, which then helped modern scientists fuel the electricity phenomenons we now have today.
The phenomenon called electromagnetic induction was first noticed and investigated by Michael Faraday, in 1831. Electromagnetic induction is the production of an electromotive force (emf) in a conductor as a result of a changing magnetic field about the conductor and is a very important concept. Faraday discovered that, whenever the magnetic field about an electromagnet was made to grow and collapse by closing and opening the electric circuit of which it was a part, an electric current could be detected in a separate conductor nearby. Faraday also investigated the possibility that a current could be produced by a magnetic field being placed near a coiled wire. Just placing the magnet near the wire could not produce a current. Faraday discovered that a current could be produced in this situation only if the magnet had some velocity. The magnet could be moved in either a positive or negative direction but had to be in motion to produce any current in the wire. The current in the coil is called an induced current, because the current is brought about (or “induced”) by a changing magnetic field (Cutnell and Johnson 705). The induced current is sustained by an emf. Since a source of emf is always needed to produce a current, the coil itself behaves as if it were a source of emf. The emf is known as an induced emf. Thus, a changing magnetic field induces an emf in the coil, and the emf leads to an induced current (705). He also found that moving a conductor near a stationary permanent magnet caused a current to flow in the wire as long as it was moving as in the magnet and coiled wire set-up.