Youngs Modulus

 One of the hardest parts of working out Youngs Modulus is working out how to read a vernier scale correctly. Needed for the thickness of the wires and the change in length.

Objective:

• To measure the Young's modulus of a piece of wire using a tensile test.

Materials:

• Piece of wire
• Tensile testing machine
• Ruler or caliper for measuring the length and diameter of the wire
• Graph paper

Procedure:

1. Cut a piece of wire to a specific length (e.g., 20 cm) and measure its diameter using a ruler or caliper. Record the length and diameter in a data table.

2. Attach the wire to the tensile testing machine and set it to apply a tensile force at a constant rate.

3. Measure the deformation (e.g., elongation) of the wire as the tensile force is applied. Record the stress (i.e., the applied force divided by the initial cross-sectional area of the wire) and strain (i.e., the deformation divided by the initial length of the wire) in the data table.

4. Repeat the tensile test at least three times with different loads (e.g., 50 N, 100 N, 150 N).

5. Plot the stress versus strain on a graph using graph paper.

6. Determine the slope of the linear portion of the curve, which is the Young's modulus of the wire.

7. Calculate the average Young's modulus of the wire based on the results of the multiple tests.

Discussion:

• Discuss the importance of Young's modulus in engineering applications.
• Compare the Young's modulus of the wire with that of other materials (e.g., steel, aluminum, wood).
• Discuss factors that may affect the Young's modulus of a material, such as temperature and humidity.

Assessment:

• Have students write a lab report summarizing the procedure, results, and discussion of the experiment.
• Have students present their findings in a class discussion or presentation.
• Have students answer questions about the experiment and the concept of Young's modulus in a quiz or exam.
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• Young's modulus, also known as the elastic modulus, is a measure of the stiffness of a solid material. It is defined as the ratio of the applied stress to the corresponding strain in the material. Young's modulus is a measure of the stiffness of an object, and is calculated by dividing the applied stress by the resulting strain. It is typically measured in units of pascals (Pa) or gigapascals (GPa). The higher the Young's modulus, the stiffer the material is. Some common materials and their Young's moduli are:

  • Steel: 200 GPa
  • Aluminum: 70 GPa
  • Concrete: 25 GPa
  • Wood: 12 GPa
  • Rubber: 0.01 GPa