♦ The formulation of the mechanical equivalent of heat was instrumental in defining the first law of thermodynamics, which describes the conservation of energy. Two stories, which stress different aspects of the scientific work, will provide insight into Joule's set of experiments by which he determined the ratio of heat and mechanical work.
Joule and energy
♦ The immediate use of solar energy is indeed known for quite some time already. This story tells you about the development of the first solar powered cookstove and the political and economical reasons, why it did not become a best practice model.
Mouchot and the solar cooker
♦ What is the nature of heat – is it a substance or infinitesimal movement of matter? Among others, the Bavarian War Minister Benjamin Thompson, later known as Count Rumford, found an answer by analysing the drilling process for manufacturing cannons.
Rumford and calorics