A mechanical system in motion could be set if we used the expansion of substances when heated and shrinking when cooling. It would be best to use substances or materials having the highest expansion characteristics at temperature changes. Many gases, mercury, alcohol and other readily evaporating liquids have such characteristics [5].
This idea could be implemented similar to a balloon or power cylinder, which expands (elongates) when filled with some similar substance. Even slight changes in air temperatures could be used for a clock mechanism.
Still, the most readily available substance is ordinary air that we inhale, we could also use oxygen, hydrogen and many other gases but it would be more expensive. Mercury is not so suitable, either as it is toxic and much more expensive. The best solution is to use air mainly.
The arrangement is made using a corrugated expandable vessel connected by means of some mechanical coupling to the clock mechanism. The driving energy source in this case will be an alternative solution [5].
