====== Heat Engine On A Wire ======

{{tag> thermodynamics heat_engine bimetallic repair unlocated}}

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{{HeatEngineOnAWire_003.jpg?400|}}

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===== Description =====

Consists of a pair of aluminum supports with holes in the center, a steel wire, and a number of small bimetallic disks.

**Very finicky. Currently not in working order.** 

(You can try, but after a number of attempts the disk would not reliably jump from side to side.)

===== Purpose =====

To demonstrate how the differing coefficients of thermal expansion in metals may be utilized. Shows a very unusual example of a heat engine.

===== Apparatus =====

  * Wire, aluminum supports, and bimetallic disks
  * [[demonstrations:9_equipment:hot_plate:start|Hot plate]]

===== Setup =====

Start by setting up the heat engine. Insert the wire into both of the aluminum supports, threading it through the hole in one of the bi-metallic disks at the same time. Place one of the aluminum supports onto a hotplate and turn it on to the maximum setting.

Place bi-metallic disk with concave (brass coloured) side down on the support that rests on the hot-plate. Once the disk has heated up to some critical value, it'll buckle (go from concave-side-down to convex-side-down), propelling it along the wire to the other support. Once it cools down, it'll return to it's original form, flipping over to the hot side once again.

===== Notes =====

It may be necessary to elevate one of the sides, should it turn out that the disk can't jump high enough from that side to reach the other.

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| **Location** | ---- |
| **Maker** | Unknown |
| **Current State** | Working |
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