• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Resistance of Carbon Putty.

Extracts from this document...




Our aim was to investigate a set of factors that affected the resistance of a mass of carbon putty.

Preliminary work:

From my physics textbook ( Physics for you by Keith Johnson), I have discovered that there are several factors that affect the resistance of a conductor:

  • Surface area: Thick wires may be regarded as equivalent to a number of thinner wires of equal area joined in parallel. Doubling the area will therefore halve the resistance. This means that the surface area is inversely proportional to its resistance.
  • Length: Double the length of the wire will double the resistance as twice the length of the wire is equivalent to two equal resistance in the series.
  • Temperature: The resistance for a metallic conductor is a constant if the temperature and other physical properties remained constant. In general, for metallic wires, the higher the temperature, the larger its resistance. But for some materials e.g. carbon and semi conductors like silicon and germanium, the higher the temperature, the lower its resistance. The resistance of most of the alloys, e.g. manganin and constantan, is only affected slightly by a change in its temperature.

The properties of Carbon:

  • Name: carbon
  • Symbol: C
  • Atomic number: 6
  • Group number: 14
  • Group name: (none)
  • Period number: 2
  • Atomic weight: 12.0107 (8) gr
  • Standard state: solid at 298 K
  • Colour: graphite is black, diamond is colourless
  • Classification: Non-metallic
...read more.















These readings clearly show a pattern in that as we decrease the length of the putty, the potential difference gets bigger and the resistance decreases. What can also be seen is that from a length of 14.5 cm where the resistance was 16.5 ohms to a length of 7.5 cm where the resistance was 7.7 ohms the resistance has almost halved. This process was very time consuming, as we had to first measure the current and then calculate the resistance. As we were also provided with an Ohmmeter I decided to measure the resistance directly.  


I am investigating the length of the carbon putty as this factor is connected to the physical effects of the putty.It is much harder to record the temperature of the conductor than to measure the length of the carbon putty. And the experiment to investigate this factor should hopefully give a good straightforward result.


I predict that as I increase the length of the putty the resistance will also increase. From all the information collected in my preliminary work I predict that as I double the length of carbon putty the resistance will also double


I ensured this was a safe experiment by:

...read more.


One error with this experiment is that the wire that connects the putty to the Power pack has its own resistance and this could have affected results. We tried to overcome this by always using the same wires, and therefore this fault was built into the system. Another error that could have occurred is the fact that the diameter of the putty was achieved by hand rolling it. This could have led to un-evenness due to different hand pressures and could also produce air bubbles.

I would like to extend this experiment by checking the resistance of putty at both above and below the length used in this one to see if the graph I have drawn is accurate. This would be above 12cms and below 2cms.

 If I was able to further extend my experiment I would like to change the diameter of the putty and see if this made any difference to the resistance.  I could use both thicker diameter than 2.2cm and/or thinner than 2.2cm.  This would enable me to compare all the results and see if the pattern held true for all thicknesses of putty.  I could use a Kenwood mincer or a spaghetti maker to ensure that the putty was the same diameter all along its length. .

...read more.

This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Electricity and Magnetism essays

  1. Investigate how mass affects the diameter of an impact crater.

    rate which proves that crater size is proportional to the square root of mass. Although the points do not form a perfect straight line, using the line of best fit it is possible to determine the sizes of craters produced by any given mass.

  2. Conducting Putty

    Output Variable: I will investigate what how changing the length of putty affects the change in resistance. I will do this by increasing the length of the putty (starting at 1cm increasing the length by 2cm each time). I will work out the value of resistance using the formula 'R=V/I' (resistance = current/voltage).

  1. Find out the relationship between resistance and conductive putty, and to see how length ...

    The same battery should be used throughout the experiment and to guarantee no results are anomalous, the experiment will be conducted three times and a mean average will be taken from each result. Prediction and Hypothesis: I predict that the resistance will be directly proportional to the length of the

  2. Find out how the length and width affect the resistance of a graphite track.

    I will also be recording the temperature each hour. I will be able to scientifically know if the external temperature affects my results. Apparatus List: A jockey so when I draw my carbon track I can place the jockey at different lengths along the line.

  1. An Investigation into how the resistance of a piece of graphite paper is affected ...

    As both the voltage and the current are output variables I have no control over them. > To get a rounded result and to also check that my results are right I will repeat the experiment again. If I don't do this then my results could be wrong without me knowing.

  2. Planning Experimental Procedures

    As the diameter increases the resistance decreases. The graph on the left shows us this. The diagram on the right is a water circuit; the pump is pumping water around the circuit. As the water passes through the wide pipe (Y) it flows quicker than it does through narrow pipe (X).

  1. Test the resistance of carbon by changing the length of the line of carbon ...

    the more resistance there will be because of the increase in the electron collisions. The number of collisions, resistance or electron scattering should be proportional to the length of the material. In the experiment I will expect for the resistance to be proportional to the length of the carbon track.

  2. Investigation in to whether the surface area or the lengths of the carbon putty ...

    I have done a preliminary test using a similar method below but I have measured the current that goes across the conductor and then calculating the resistance from the data I have collected. In the preliminary experiment, I was trying to measure the current passing the carbon putty, as it

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work