Columbia University Physics Lecture Demonstrations


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4B30.1 Different Conductivity in Iron and Copper

[Setup Time: 30 Min.] [Current Condition: OK]

Info

An iron and a copper rod are heated simultaneously. Blocks fixed to each of the rods by wax will fall off at different rates.

[Note: This demonstration does not work very well and is tricky to set up.]

Setup Instructions

1. Ignite the Bunsen burner.

2. Scrape a bit of wax off the metal attachment on the block and roll it into a ball. (You may want to heat the metal portion briefly so that the wax is soft.)

3. Place the little wax ball on top of the metal portion of the block and place the block on the support jack.

4. Slide the jack under the rod to which you wish to attach the block.

5. Turn the knob on the jack so that it raises the top of the metal part of the block to the bar.

6. Heat the wax to soften it and then raise the jack slightly. Allow the metal on the block to cool and then proceed to attach the next block.

Note: Although up to six blocks may be attached, the demo can be set up with only two or three blocks. Also, the blocks should be placed closer rather than further apart from the heat source as it takes some minutes of heating for the blocks to begin to fall off.

Parts List

Stands with Bar (labeled Cu and Fe) in D. Thermo, 1B

Wooden Blocks with metal attachment in L. Misc

Bunsen Burner in D. Thermo, 1A

Support Jack (small) in L. Misc

Candle in D. Thermo, 1B

Relevant Simulation

Demo Example:

Other Information

Melting Wax

Real-Life Examples

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More Advanced Reading

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