Test wire should be thin and as long as possible. Longer and thinner wire - more extension for the same force, reduces uncertainty.

Find CSA. Use micrometer to measure diameter of wire at three points along the wire, work out an average. Assume the cross section is circular, use: area = πr^2.

Clamp the wire to a bench, hang weights off one end of it. Start with the smallest weight necessary to straighten the wire (not included in calculations).

Measure distance between fixed end of wire and marker.

Increase weight - wire stretches, marker moves.

Increase weight in steps, recording marker reading each time - extension = difference between reading and unstretched length. Use mass meter or digital scales to accurately find weight you add with each step.

Use results to calculate stress + strain and plot stress-strain graph.

Use this experiment to find fracture stress, add weights to wire to roughly find force required to break wire. Repeat with identical wire but add weights in small increments, helps you find breaking force more accurately.

## Comments

No comments have yet been made