To find the resistance of wire.

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Physics GCSE Practical Assessment

Investigation the resistance of wire

Aim: To find the resistance of wire.

In the past in school lessons I have learnt things to do with circuits and resistance. I know how to use formulas to work out the resistance of certain things and know how to use equipment such as Voltmeters and Ammeters, I also know how to set up circuits that use these things.

Variables

The following is a list of variables I could change in the investigation:

  • Temperature
  • Length of wire
  • Thickness/Diameter
  • Voltage across wire
  • Current through wire
  • The type of wire

I am going to investigate what will happen to the resistance when I change the Length of Wire. I am using this variable because most of the other variables would be to simple or to complicated to use: The temperature of the wire would be hard to record because it is near impossible to find the temperature of the wire with the equipment I have. The thickness of the wire is hard to measure to, It could be done be it wouldn’t be a very precise experiment. I did not choose to change the type of wire because of the simple reason that I cannot plot the results on a line graph, which is a better way of analyzing my results.

To make the experiment a fair test I am going to keep the temperature, the thickness, the voltage, the current and the type of wire all the same. By doing this my results will be kept controlled and none of my results will be influenced by other things such as thickness or current.

Prediction

I predict that when I change the length of the wire the resistance will @-)----

After researching using books and the internet I have found more detailed scientific knowledge to explain my prediction:

In order for things to react together their particles must collide with each other and must be charged with enough energy. In a successful collision particles are used up and eventually the particles get fewer and then stops, on a graph this would look like the gradient of the line gradually gets shallower until the reaction stops and the line straightens out completely.

There are lots of different things that can speed up the rate of reaction like temperature, when temperature is increased it causes particles to move much quicker making particles collide more often resulting in more successful collisions and the rate increases. One thing that can speed up the rate of reaction is adding a catalyst. Catalysts speed up the rate of reaction but are never used up so can be used over and over, this makes them common in industry and they can be found in the Brewing Industry where yeast, an Enzyme (a biological catalyst) is used in fermentation. Increasing the surface area of something increases the chance of collisions and so also increases the rate of reaction. The variable I am going to change is the Concentration of the acid, the greater the level of Concentration the more reactant particles there are in the solution. This will cause more collisions and so the rate of reaction will be increased.

Join now!

In my experiment Hydrochloric Acid (liquid)(HCl) is going to react with Marble Chips (solid)(CaCO3) to make Calcium Chloride (liquid)(CaCl2), Water (liquid)(H2O) and Carbondioxide (gas)(CO2):

CaCO3 + 2HCl        CaCl2 + H2O + CO2

In this reaction energy is taken in, in order to break the bonds between the atoms. More energy is taken in then given out so the reaction is endothermic.

Procedure

Apparatus

Here is a list of apparatus I will use:

  • A Burette
  • A Measuring Cylinder
  • A Beaker or Tub
  • A Boiling Tube
  • 10ml of Acid
  • Water
  • 1 gram of small Marble ...

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