Are these objects made cooler by the melting of the ice? They are made cooler by the melting of the ice. What effect does salt have upon ice? Salt makes the ice melt more rapidly. When salt and ice are placed around a vessel of cream, what takes place? The salt causes the ice to melt quickly, and the ice in melting takes so much heat from the cream as to freeze it, thus making it ice-cream. Ebullition. What is meant by ebullition? _Ebullition_ means boiling. When is a liquid in a state of ebullition? When it has been heated so as to boil. Can solids be made to boil? No; liquids only can be made to boil. What change takes place when a liquid boils? The liquid is changed into a vapor or gas. What becomes of water when it is boiled? Water when boiled passes off into steam. What is necessary to make water boil? Heat is necessary to boil water or any other liquid. How much heat is contained in boiling water? Two hundred and twelve degrees of heat. When water passes into steam, how much is its bulk increased? About seventeen hundred times. How much steam will a pint of water make? A pint of water will make about seventeen hundred pints of steam. What do bubbles of boiling water contain? They contain steam. Why are these bubbles formed? Because the water at the bottom of the vessel is heated and changed into steam, which expands and forms the bubbles. Why do these bubbles rise to the surface? Because steam is lighter than water. When does water simmer? When water is heated, the steam at first forms in very small bubbles at the bottom of the vessel, and as these bubbles rise through the colder water, the steam in them is condensed to water, so that they break before reaching the surface, thus producing what is called “simmering.” When does water boil? Water boils when it becomes heated so that the bubbles rise to the surface of the water before breaking. Why will a vessel full of water run over when heated? Because the water is expanded by heat, and some of it must run over. Why will the water boil over when the vessel is not full? Because the steam, in trying to escape, throws some of the water over the edge of the vessel. Vaporization. When water is boiled, what change does it undergo? It is changed into a vapor, called steam. What is this process called? It is called _Vaporization_. What is meant by vaporization? Vaporization is the changing of a liquid into a vapor, by boiling. What is necessary to change a liquid into a vapor? Heat is necessary to change a liquid into a vapor. At what temperature is water changed into steam? At the temperature of two hundred and twelve degrees. Are all liquids changed to vapor at the same temperature? No; they vary very much in the amount of heat required. Ether boils at 96 degrees, alcohol at 176 degrees, and quicksilver at a temperature of 662 degrees.