|
|
Code Number: 4A30.10
Demo Title: Expansion & Contraction Demo - Bimetal Strip
Condition: Good
Principle: Expansion & Contraction with Temperature Variation
Area of Study: Thermodynamics
Equipment:
Bimetal strip, Gloves, Bunsen burner, Grill Lighter.
Procedure:
Place the bimetal strip directly into the flame of the Bunsen burner. The strip should immediately start to bend. The strip can be bent to almost 90 degrees, if a 3 inch portion is heated. The bimetal strip is made out of Invar Steel and Brass that has been laminated together.
A variation on this theme is to take one of the newer bimetal strips on which you can see the silver and the brass side and dip it in liquid nitrogen. Take it out of the liquid nitrogen and observe the direction of the bend. Now place it in the flame of a Bunsen burner and observe that it will bend towards the opposite side of the bimetal strip.
The set of compound bars has pairs of Brass/Aluminum, Brass/Iron, Copper/Iron, and Brass/Copper.
References:
- H. Richard Crane, "Popping Bimetal Can Keep You Warm or Cool", TPT, Vol. 36, # 5, May 1998, p. 302.
- Philip B. Allen, "Conduction of Heat", TPT, Vol. 21, #9, Dec. 1983, p. 582.
- "The Thermal Expansion of a Soda Straw", TPT, Vol. 16, # 9, Dec. 1978, p. 632.
- Peter W. Hewson, "The Bimetallic Strip - A Quantitative Experiment", TPT, Vol. 13, # 6, Sept. 1975, p. 350.
- Peter W. Hewson, "Wrong Determination", TPT, Vol. 13, # 7, Oct. 1975, p. 448.
- Thomas B. Greenslade, Jr., "Bimetallic Thermometer", AJP, Vol. 93, #3, March 2025, p. 209.
- Ha- 5: Freier and Anderson, A Demonstration Handbook for Physics.
- H-110: "Bimetallic Strip & Flag Waver", DICK and RAE Physics Demo Notebook.
- George M. Hopkins, "Hygrometry", Experimental Science, p. 197.
- Charles Vivian, "A Lively Celluloid Fish", Science Experiments & Amusements for Children, p. 47.
- Tik Liem, "The Curving Tape", Investigation to Science Inquiry, p. 21.
- Joseph Frick, "# 346 - Expansion of Solids", Physical Technics: Or Practical Instructions for Making Experiments in Physics and the Construction of Physical Apparatus with the Most Limmited Means, p. 412.