Quick Answer: The Bi-Metallic Strip is two different metals joined together that bends when heated, showing that metals expand at different rates. It is used to demonstrate thermal expansion and the working principle of a thermostat.
Last updated: October 2026
Key Features
Two different metals joined into one strip
Bends on heating toward the metal with the lower expansion
Returns toward its original position as it cools
Held in a clamp and heated gently with a laboratory heat source
Explains thermostats, circuit breakers, fire alarms and electric irons
Heated gently, the strip curls visibly, giving students direct evidence that solids expand by different amounts. Teachers then link the movement to automatic switches in thermostats, electric irons and circuit breakers, where a bending strip controls an electrical circuit. Educational Instrument can arrange export supply of the Bi-metallic strip to Vanuatu, Iceland, Uganda, Jordan, Luxembourg and Barbados.
Frequently Asked Questions
Which way does the Bi-Metallic Strip bend when heated?
It bends toward the metal with the lower expansion, because the other metal expands more. On cooling it returns toward its original position.
