But when the tragic incident occurs between those who are near or dear to one another--if, for example, a brother kills, or intends to kill, a brother, a son his father, a mother her son, a son his mother, or any other deed of the kind is done---these are the situations to be looked for by the poet.
When water is heated it expands. For example, water heated from 90Â°F to a thermostat setting of 140Â°F in a 40 gallon hot water heater will expand by almost one-half gallon.
The water at the bottom of the pot heats up first. This causes it to expand. Since the warmed water has a lower density than the water around it, it rises up through the cooler, dense water. At the top of the pot, the water cools, increasing its density, which causes it to sink back down to the bottom. This up and down movement eventually heats all of the water.