pUKPhysicsUKTHE INVESTIGATION LABS

A LEVEL / MECHANICS & MATERIALS

Materials & Elasticity

Slotted massesClick to add · drag onto a hanger
Select a specimen. Zero the unloaded gauge, then add masses to start.

YOUR EXPERIMENTAL EVIDENCE

Measure. Plot. Explain.

Analyse your readings

Capture at least three different extensions for a fit.

Fit the linear elastic region to find stiffness or Young modulus. A good fit alone does not prove elastic behaviour.

Readings table · 0 readings
Station Source Time / s Force / N Extension / mm Stress / MPa Strain / %

Your first experiment

  1. Measure: read the ruler and use the micrometer. Close its jaws gently, then record the diameter.
  2. Zero: zero the gauge with no added masses.
  3. Load: click a mass, drop it onto the hanger, or enter a load. Loading starts automatically. Wait for a steady reading.
  4. Capture: save a reading. Repeat at several loads, then fit the linear part of your graph.
  5. Compare: show two stations and link their loads. Measure and zero each one. Keep a curve to compare investigations.

Record collects readings at 10 Hz while Run is active. Pause stops loading and time. Unload removes the added load gradually. Export CSV before clearing your notebook or changing investigation.

Changing a specimen gives it a new measurement series. Kept curves remain until removed; Save setup and local recovery restore fresh, unloaded specimens, not readings or damage.

Micrometer

Close the jaws onto the specimen. The ratchet stops at contact. Resolution: 0.001 mm; ideal zero error.

2.500 mm

Close the jaws before recording.

Model & controls

A slow-loading materials experiment

Loads ramp at 0.6 kg s⁻¹ and each reading is a quasi-static equilibrium. Oscillations, inertia, specimen self-weight, temperature, creep and necking are omitted. The hanger is counterbalanced; added mass produces F = mg, with g = 9.81 N kg⁻¹. Apparatus is schematic and extension motion is magnified. Read the gauge for actual extension.

Wires use engineering stress F/A₀ and strain ΔL/L₀. Metals are initially linear elastic, then follow an illustrative strain-hardening law; unloading has the original elastic slope and leaves a permanent extension. Glass breaks elastically. Rubber uses an ideal nonlinear elastic model with no hysteresis. Springs obey F = kΔL throughout the supported range. Model material constants and breaking strains describe teaching specimens, not certified material data.

Force resolution is 0.01 N, gauge resolution 0.001 mm, ruler resolution 1 mm and micrometer resolution 0.001 mm. Stress and strain graphs use your recorded dimensions. A gauge over range or fractured sample has no valid extension reading. Zeroing damaged material is disallowed so permanent extension cannot be erased.

Model elastic energy is recoverable energy at the current load. Plastic work is accumulated irreversible deformation work in this ideal law. The measured graph area is signed work between recorded points, including unloading; it is not always stored energy. A complete closed loading cycle returns to its starting point. Fracture energy and the falling load are not simulated.

Keyboard and camera

Space Run/Pause · C capture · Z zero · X unload · F focus · [/] select station · arrows adjust target mass by 50 g (Shift: 10 g) · Escape cancel. Ctrl/Cmd+Z and Shift+Ctrl/Cmd+Z undo/redo paused, unloaded setup edits.

Drag the hanger down/up to preview a larger/smaller load. Drop a tray mass onto a highlighted hanger. Scroll to zoom about the pointer; right/middle drag or Pan moves the view. Whole bench resets the camera. Lock apparatus prevents edits while retaining measurement and camera access.