Resistance of a Wire
Aim:
To find out how the length of the wire affects the resistance in an
electric current.
Variables:
All the possible factors that could affect the resistance of a circuit
are the temperature, length, material and width of the wire. One of
these I am going to chance for my input variable and the others I will
keep the same for my control variable.
Input variable:
I am going to experiment with the length of the wire and see how that
can change the resistance.
Outcome variable:
What I believe shou[IMAGE]d be affected by the input variable is the
resistance.
Control Variable:
I am going to keep the temperature, width and material the same so
that they won't be able to modify my results and give me false
information about resistance.
Apparatus:
· Wire
· Crocodile clips
· Battery
· Resister
Measuring devices:
· Voltmeter
· Ammeter
Prediction:
In a circuit there is electricity that flows through a wire.
Electricity is the flow of electrons, which is also called the
current, measured in Amps. The amount of energy that is given to the
electrons is the voltage, the higher the voltage the more energy
measured in Volts. Resistance through takes place within the circuit.
The environment that that current is in affects the amount of
resistance. Resistance causes an opposition flow to the current on the
circuit; it slows down the electrons in the circuit. To work out the
resistance, Ohms law is needed. This is Voltage = Current x
Resistance.
In my experiment I believe that resistance will take place. There is a
Voltmeter and an Ammeter to measure the current and I will use Ohms
law to work out the resistance.
I believe that the resistance in the circuit will increase, as the
wire gets longer. This is because it will take longer for the
electrons to go down the long wire than a shorter wire.
A sample of children ranging from 4 to 13 years old are going to be asked to watch a Rainbow Brite video. The children will be randomly picked from a childcare center. To ensure that the children are going to be randomly assigned, the children will range in different age groups. The first group will consist of 4, 6, and 8 year olds. The second group will consist of 10,12, and 14 year olds. It would have to be a field experiment because you have to go out and collect the data.
I want all that you come with—your baggage and past mistakes, the wa able (or 'criterion variable ') changes when any one of the independent variables is
The input variables are the ones that I can change in order to affect the experiment and the outcome variables are the ones I will measure to see how the input variable has affected it. Input Variables --------------- Amount of calcium carbonate Amount of hydrochloric acid Surface area of calcium carbonate Concentration of hydrochloric acid Temperature of hydrochloric acid Introduction of a catalyst Outcome variables ----------------- Amount of calcium chloride released Amount of water released Amount of carbon dioxide released Change in weight
I will repeat this for all of the different diameters that I will test. but remember to keep the length of the wire the same throughout. The apparatus that I will use for this experiment are listed below. Power supply - This will be 3V of power and will be used to power
have to be across the wire and not just anywhere in the circuit so it
I also decided to use a wooden block to keep hold of the wire, because
8.) Balance – I chose this, as it is very precise (it measure to 2
The tennis ball is the constant variable factor (the variable that is kept the same, to make the investigation valid). The ball will dropped from increasing heights (cm-25, 50, 75,100,125,150,175,200) and the bounce of the ball will be measured. A sample size of 3 results will be taken from each height the ball is dropped. The same investigation will then be repeated, but one of the independent variables will be changed.
F Another wire, or exact same properties (Nickel Chrome, thickness 34). mm and length 30cm) was placed on top of the previous wire, in the same position, both straight and flat. F. The power was turned on again and the same procedure was repeated. recording current and voltage at three points on the variable. resistor.
of the atoms, so if there are more or larger atoms then there must be
Cross-sectional area/ width: If the cross sectional area is increased there is more space for the electrons to move freely making less collisions so more current will pass through making the resistance decreased. I have done a diagram below. [IMAGE] [IMAGE] Small wire Large wire Length: If the length of a wire is increased there are more atoms for the electrons to collide with. There for less gets through meaning the current is less so the resistance is increased.
The specimen must be regularly shaped in the form of a wire; its diameter. should be measured at six different points. Variables and Controls:. The variables that I will be using are the length and diameter of the
Independent variables: The temperature of hcl gas will be decreased and increased throughout the experiment.
4. Question d: Explain the variables you should take into account when assessing page 4