• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10

The elasticity of copper investigation

Extracts from this document...


The elasticity of copper investigation


The aim of this experiment is to investigate how the extension of a length of wire is affected by the force. I will then find stress and strain after finding these variables, for which I can finally complete my objective which is to find the young’s modulus for the material, in this case copper wire.


I predict that when a wire is subjected to a stretching force, in this case wire being pulled by the force of weight, then the wire likely to be stretched. This does depend on the material as the more flexible the material is the more possibility there is of stretching. I think that the copper wire will have a young’s modulus of about 130 GPa, as the secondary source has worked this out

The stretching force which extends material by equal steps is called Hooke’s law. image00.png


Stretching force, F = spring constant, k * extension, Δx

(N)                                (N 1/m)                 (m)

So the lower the gradient the more flexible the spring will be, vice verser.

This formula can be used to calculate the spring constant, which means that we can work out the force needed to extend the copper wire by 1 metre. So we can predict the amount of extension of the copper wire when adding Newton’s.  

Δx = stretched length – original length

k, can also be referred to as stiffness

The point before X is the limit of proportionality (F α x) it is where the strain is proportional to stress. Point X is called the elastic limit

...read more.


‘The ultimate tensile stress is the measure of strength.’

This is when the material is likely to break so can no longer stretch, but will not be testing this in my experiment.

Strain: the extension per unit length produced when an object is stretched or squashed. This has no unit because it is a ratio.

Strain, ε = Extension, Δx (m)

    Original length, L (m)

For e.g. if there were two wires different lengths, everything else same, the longer wire would be under more strain.

‘It stretches by the same fraction of its original length.’

Young’s modulus: this is the ratio of stress to strain in a material when it is stretched, provided Hooke’s law is obeyed.

Young’s modulus, E = Stress, σ (Pa)

                           Strain, ε



  1. Gather all apparatus in one place safely, then setup the apparatus up like diagram shows.image04.pngimage03.png
  1. Measure the length of wire on the metre rulers, ensuring the wire is taught and straight along the rulers. Measure the diameter along the wire, at least in three different places (as the wire may not be the same everywhere). Place the sellotape pointer on the wire, any where as long as it is against the rule and take own these results.
  1. The wire may have to be long to see a significant change in extension; however the temperature may affect the length. I suggest that a preliminary experiment take place to work this out.  
...read more.


R-squared value: An indicator from 0 to 1 that reveals how closely the estimated values for the trend line correspond to your actual data. A trend line is most reliable when its R-squared value is at 1 or near 1. It is also known as the coefficient of determination.


The uncertainty of the extension is 0.01cm  

(0.01/1.7)*100 = 1.7%

The uncertainty of the length of wire is 0.001m

(0.001/1.760)*100 = 0.05%

The uncertainty of the diameter of the wire is 0.01mm

(0.01/0.31)*100 = 3.1%

To ensure I had a safe experiment I wore safety goggles, also setup the experiment in the centre of the table.

I made sure that the clamp stand was firmly placed on the floor so that it wouldn’t wobble and affect the results taken down.

I tried to keep my eye level in line with the marker measurements to rule out parallax error.

I took many results down to have accurate results and averaged them.

The reason for the line of best fit not going through the origin there may have been due to systematic error. This may because there was friction on the pulley, to remedy this problem grease could be used. Also the ruler was not long enough for the whole wire to be measured so the 2 rulers may be disjointed, so to remedy this problem I would need a longer ruler. Also the taught wire may not be horizontal to the pulley when tied to the clamp so the wire is longer than it can be measured, to solve this problem I used a wooden block, but it wasn’t enough.

The main two measurements that contributed to young’s modulus were the diameter and the extensions as they were used to calculate the stress and strain.  

...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. Marked by a teacher

    Investigate young's modulus behind Constantan and Copper.

    4 star(s)

    The pulley, which I had used, lets the wire slot into place and lets the wire freely move allowing no added pressure onto the wire, so the wire only receives pressure form the weights which are added on. Before attaching any weights, the first thing I would do is beside

  2. Marked by a teacher

    Draw stress and strain graphs for the metal copper and the alloy constantan. Calculate ...

    4 star(s)

    So hence it would take more load to create an extension for the alloy. Hence constantan would be stiffer and so this is why its young's modulus would be higher than that of copper. The young's modulus would tell me how stiff a material is when it is stretched.

  1. Marked by a teacher

    Investigating the young modulus of a wire

    3 star(s)

    * A 100g weight hanger- To hang weights on. Method 1. Using the "G"clamp provided, fix one end of the 1.5metre long wire on clamp making sure it is tightened and secure. 2. Using the right length of table in conjunction to the 1.5 metre long wire, fix the pulley provided securely on the table making sure it is tight and firm.

  2. Resistance of a Wire Investigation

    Different form the manufactures line. This is a percentage difference of approximately 8%, using the formula: Difference ? Original X 100 This shows that the results were good, as 8% is a very small margin of error. The error bars on the graph show that the most inaccurate result was the 60cm result.

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

    Therefore, in order to conduct an accurate experiment, the height will need to be kept constant. In addition, from these findings I have decided I will use a height higher than the ones experimented. This will allow me to notify the trend of varying mass in detail.

  2. To plan an experiment to measure the extension in a piece of copper wire, ...

    it stays elastic in this sense. The yield stress of a material is the value of the stress at its elastic limit. * Yield point. The point, just after the elastic limit, at which a distorting force causes a major change in a material.

  1. Testing the strength of electromagnets

    this should will increase the size of the magnetic field increasing the strength of the electromagnet itself. Results table Paper clips picked up No. of coils Test 1 Test 2 Test 3 Average 0 0 0 0 0 5 1 1 2 1 10 5 8 6 6 15 11

  2. Find out if the motion of an elastic band changes, by the rate of ...

    If everything goes accurately and correctly then I will use this list of apparatus for my real experiment. Elastic band Meter stick Measuring tape Laboratory chair Preliminary Experiment In order to obtain the best results possible, we carried out some preliminary work in order to identify appropriate ranges and values, to be used in the final experiment.

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