How can you test hair elasticity?

• A. Soak hair in water and check swelling.
• B. Perform a wet or damp strand test by stretching a strand to see if it returns to shape without breaking.
• C. Apply heat and observe stretch.
• D. Perform a dry strand test by stretching a dry strand.

Answer: (B)

Elasticity is how well hair can stretch and then return to its original length after tension. The most accurate way to test this is with a wet or damp strand test: take a strand while it’s damp, gently stretch it, and release. If it springs back to its original length without breaking, the hair has good elasticity. If it stays stretched or breaks, elasticity is poor or the hair is damaged. Water makes the cortex more pliable, so observing the strand while it’s damp reveals the hair’s true elastic behavior.

Soaking hair in water and watching for swelling mainly shows porosity and how the fiber swells, not how it recovers after stretch. Applying heat can alter the hair and isn’t a reliable measure of natural elasticity. A dry strand test can indicate brittleness in dry hair, but it doesn’t reflect how hair behaves when it’s normally handled or styled when damp, so it isn’t the best test for elasticity.