Young's modulus of copper by projecting a laser

In summary, the conversation discusses an experiment performed in lab to find the Young's modulus of copper using a laser and a wire. The lab instructor explains that using a meter stick does not affect the precision of the experiment due to the relationship between stress and area. The speaker is still confused and asks for further explanation. Another person suggests watching a lecture for clarification. They also ask for a description of the experiment and why the meter stick may have been thought to cause a loss of precision.
  • #1
negat1ve
24
0
Not really a problem but a concept I am having trouble understanding and I was hoping someone can explain to me better.

We performed an experiment in lab last week on finding the Young's modulus of copper by projecting a laser on the wall to magnify the effect of the change in length of the wire.

Our lab instructor told us that the precision of the experiment is NOT ruined from using a meter stick because that stress determines the order of magnitude. And that a small area means a huge stress cause of the relationship S=F/A.

Can someone please explain this to me better why the experiment is not ruined from using the meter stick. I am still a little confused. Thanks alot!
 
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  • #2
Not sure I understand exactly what you are confused about.

You might find this lecture useful however:

https://www.youtube.com/watch?v=YrRP-oGPjvk
 
  • #3
It unclear to me too where the "meter stick" comes into play. Can you describe the experiment and also explain why one might have thought the meter stick would cause a loss of precision?
 

1. What is Young's modulus?

Young's modulus is a measure of the stiffness or elasticity of a material. It describes the relationship between the stress (force per unit area) applied to a material and the resulting strain (change in length or deformation) that occurs.

2. How is Young's modulus measured?

In the case of copper, Young's modulus can be measured by projecting a laser onto a thin strip of copper. The strip will deform under the stress of the laser, and the resulting strain can be measured using specialized equipment. By varying the stress applied by the laser, multiple measurements can be taken to determine the relationship between stress and strain.

3. What factors can affect Young's modulus?

The Young's modulus of a material can be affected by various factors, including temperature, impurities, and crystal structure. In the case of copper, temperature can have a significant impact on its elasticity. As temperature increases, the atoms in copper vibrate more, making it easier for the material to deform under stress. Impurities can also disrupt the regular arrangement of atoms, affecting the material's stiffness. Lastly, the crystal structure of copper can also impact its Young's modulus. For example, pure copper has a face-centered cubic structure, while impure copper may have a more complex crystal structure, resulting in different elastic properties.

4. What is the typical value for Young's modulus of copper?

The Young's modulus of copper can vary depending on factors such as temperature, impurities, and crystal structure. However, at room temperature, the average value for Young's modulus of copper is around 117 GPa (gigapascals) or 17 million psi (pounds per square inch).

5. How is Young's modulus used in practical applications?

Young's modulus is a crucial parameter in engineering and materials science, as it helps determine a material's ability to withstand stress and strain. It is used in the design and testing of various structures and components, such as buildings, bridges, and aircraft. In the case of copper, its high Young's modulus makes it a suitable material for electrical wiring and plumbing, as it can resist deformation and maintain its shape under stress.

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