(2) Contrast Between Thermodynamic and Biological Terminology: Note that because of historical accident, students encounter a possible source of confusion between the terminology of physics and biology. Whereas the thermodynamic terms "exothermic" and "endothermic" respectively refer to processes that give out heat energy and processes that absorb heat energy, in biology the sense is effectively inverted. The metabolic terms "ectothermic" and "endothermic" respectively refer to organisms that rely largely on external heat to achieve a full working temperature, and to organisms that produce heat from within as a major factor in controlling their bodily temperature. (3) Examples: Photosynthesis, Melting ice, Vaporising Rubbing Alchool, Thermal decomposition reactions, Forming a cation from an atom in the gas phase, Dissolving ammonium chloride in water. High-energy neutrons can also produce tritium from lithium-7 in an endothermic reaction, consuming 2. 466 MeV. This was discovered when the 1954 Castle Bravo nuclear test produced an unexpectedly high yield. ₃Li (Lithium-7) + n (Neutron) →  ₂He (Helium-4) + ₁T (Tritium-3) + n (Neutron)