User Tools
demonstrations:4_thermodynamics:4f_entropy_and_the_second_law:thermobile:start
Differences
This shows you the differences between two versions of the page.
| Next revision | Previous revision | ||
|
demonstrations:4_thermodynamics:4f_entropy_and_the_second_law:thermobile:start [2019/02/14 23:33] 127.0.0.1 external edit |
demonstrations:4_thermodynamics:4f_entropy_and_the_second_law:thermobile:start [2020/02/03 20:49] (current) demoroom |
||
|---|---|---|---|
| Line 1: | Line 1: | ||
| ====== Thermobile ====== | ====== Thermobile ====== | ||
| - | {{tag> needs_review untagged unlocated}} | + | {{tag> heat_engine thermodynamics shape_memory_effect nitinol unlocated}} |
| <WRAP box right> | <WRAP box right> | ||
| Line 11: | Line 11: | ||
| ===== Description ===== | ===== Description ===== | ||
| - | Simple heat engine | + | Stored in a small box with the branding 'Thermobile' on it. A plastic chassis connects two wheels, one bigger one made of plastic and a smaller one made of brass. Around them is a loop of nitinol- a shape memory alloy- that has been 'trained' to straighten when heated up. |
| - | + | ||
| - | + | ||
| - | + | ||
| - | Dip the wheel into water ~60'C (requires an approximate 35'C temperature difference across the wheels) and wheels will start spinning. This simple engine work due to the metal wire regaining it straight shape when it reaches a warm temperature. Updated on: 06/20/13 | + | |
| ===== Purpose ===== | ===== Purpose ===== | ||
| + | Illustrate another example of the huge variety of heat engines. Demonstrate the action of a much simpler heat engine, and show what unites all heat engines: a heat differential. | ||
| ===== Apparatus ===== | ===== Apparatus ===== | ||
| + | * 'Thermobile' Heat engine | ||
| + | * Cup of hot water (~60ºC) | ||
| + | * [[equipment:lab_stands:start|Lab stand and clamp]] (Optional) | ||
| ===== Setup ===== | ===== Setup ===== | ||
| + | Dip the bottom edge of the brass wheel into the cup of hot water (this demo requires an approximate 35ºC temperature difference across the wheels to run), give the wheel a spin, and it should continue on it's own. | ||
| + | It may be helpful to mount the thermobile on a lab stand so that the demo may be more easily shown. | ||
| ===== Notes ===== | ===== Notes ===== | ||
| + | This simple engine works using a more complicated principle: the [[wp>Shape-memory_alloy|shape memory effect]]. When the wire is bent around a wheel and heated, it will exert a force attempting to straighten itself out. Once the wheel is given a spin, a temperature asymmetry will cause more force to be exerted on one side of the thermobile, so it continues to spin. | ||
| <WRAP group> | <WRAP group> | ||
| Line 47: | Line 47: | ||
| </WRAP> | </WRAP> | ||
| <WRAP tablewidth 100%> | <WRAP tablewidth 100%> | ||
| - | | **Location** | ---- | | + | | **Location** | C3 | |
| | **Maker** | Unknown | | | **Maker** | Unknown | | ||
| | **Current State** | Working | | | **Current State** | Working | | ||
demonstrations/4_thermodynamics/4f_entropy_and_the_second_law/thermobile/start.1550187203.txt.gz · Last modified: 2019/02/14 23:33 by 127.0.0.1
Page Tools
