How does one prove that all metal bars expand when heated in a scientific way? Thanks for your help?

Question

Philosophy

Guys, i meant that ALL metal bars expand when heated. Experiments cannot prove all do. Thanks for your help though!

Answer 1

Make an experiment!

Hypothesis: All metal bars expand when heated.
Corollary: All metal bars reduce when cooled.

Materials: metal bars of all known metals, micrometer, (method of heating), (method of cooling)

Method:
- At room temperature, measure volume of each sample material using micrometer. Record data.
- Apply heat to each sample; measure material volume when 'hot' (i.e. raise temperature of sample at least 100 C). Record data.
- Allow material to cool to room temperature. Measure material volume; record data.

Observations: (Did material expand when heated? How much? Did it reduce when cooled? Did it match the original measurements? Etc)

Conclusions: Metal bars do/do not expand when heated. Metal bars do/do not reduce when cooled.

Answer 2

CanTexans answer is good. There is an easy way to see it for yourself without going to a lab.

This summer go to the nearest railroad track and look at the gap between each section of rail (Look for trains first, haha). Since metal expands when heated, the gap should be very small. Note your exact location and go back in the middle of winter and measure the same gap. You will notice that the gap is significantly wider than it was during the summer.

The change in length of a piece of steel material can be quantified by the following expression.

Delta L = (6.5E-6)(the change in temperature)(the length of the steel).

the coefficient of expansion for steel = 6.5E-6

Here is an example:

A piece of steel is exactly 40 ft long at 60 degrees F. Find the length at 100 deg F, assuming the ends are free to move

change in length = (6.5E-6)(100-60)(40 ft) = 0.0104 ft or approximately .1248 inches or about 1/8 of an inch.

Answer 3

particular - the final rule is that metals improve on heating and settlement on cooling - besides the undeniable fact that there are exceptions. As yet another guy or woman responded - Antimony unquestionably expands slightly because it solidifies from the molten state. because of this supplies it became used as a constituent of style steel - by way of fact the molten steel cooled it accelerated slightly and gave a sharper definition to the type that had merely been forged.