Stress & Strain

Young’s modulus

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Stress $\sigma = F/A$; strain $\varepsilon = \Delta L/L$.
• Young's modulus $E = \sigma/\varepsilon$ measures stiffness.
• Steel (200 GPa) is about 10 times stiffer than bone and 20 times stiffer than wood.

Steps

1. Fair comparisons
2. The stress in a wire
3. How much does it stretch?
4. Twice as thick
5. Thick enough
6. Safety margin in a bone