Bimetallic Strip - A simulation

Bimetallic Strip Simulator

Change the metals and temperature. Watch how one metal tries to become longer than the other, causing the joined strip to bend.

Top: Brass Bottom: Iron

Swap Reset Animate

Bend: The strip bends toward the metal that expands less.

Key idea: The two layers are joined, so they cannot expand freely. Instead, the strip curves.

1) Choose metals

Top metal 19.0 ×10⁻⁶ /°C

Bottom metal 11.8 ×10⁻⁶ /°C

Brass + Iron Zinc + Invar

2) Change temperature

Temperature 80 °C

Reference temperature 20 °C

Bend visibility Medium

Room temp Heat strongly

Show expansion arrows

3) Live results

Temperature change

+60 °C

Bend direction

Down

Longer side

Top: Brass

Shorter side

Bottom: Iron

Student checkpoint

Which metal becomes the outside of the curve when the strip is heated?

Show answer

The metal that expands more becomes the outside of the curve. The strip bends towards the metal that expands less.

Teaching note: the bend is exaggerated so students can see the effect clearly. Formula behind the idea: expansion = α × original length × temperature change.