Compound Strip (Bar)
Thin strips of two different metals are laminated together in this simple demonstration, also known as a Bimetallic Strip.
Background
The Compound Bar, also known as a Bimetallic Strip, is made of two different metals (brass and Iron)
laminated together. When heated, the metals expand. But one metal expands more than the other, and
that causes the strip to bend. Try cooling the strip by dipping it in ice or liquid nitrogen. Do you think it will bend the same way?
Bimetallic strips can be used in thermostats. The strip is curled into a loop and, as the temperature
changes, the loop curls and uncurls. When the temperature goes down, the uncurling loop makes an
electrical contact that turns the heater on.
Activity
Hold the insulating handle. Put the metal strip in the flame of a burner. Observe as the strip curves to
one side.
Take care not to touch the bar until it is completely cool.
Key Features
- Dual-Metal Construction: Typically made from two different metals (such as brass and steel), bonded together to show the contrasting rates of expansion.
- Robust Build Quality: Engineered with high-quality metals to ensure durability and repeatable performance during experiments.
- Clear Thermal Response: When heated, the bar bends due to unequal expansion of the two metals, offering a visual and measurable demonstration of thermal expansion.
- Educational Use: Ideal for school and college physics labs to explain the concept of bimetallic strips used in thermostats and heat-sensing devices.
- Safe & Easy Handling: Comes with insulated handles or mounting options for safe classroom demonstrations.