science teacher's guide - DepEd Naga City

Teacher's GuideModule 1: SolutionsProcedure1. Place ½ cup of cold water in a cup.2. Place ½ cup of hot water in another cup.3. At the same time, add ½ teaspoon of coffee to each cup.4. Stir each solid for 10 seconds and observe.5. Stir for another 10 seconds and observe again.Expected results: The coffee in hot water will make the color of water darkbrown or black. The coffee powder will dissolve faster in hot water. In coldwater, there will be some coffee particles remaining that did not dissolve.With more stirring, the coffee in the cold water may also completely dissolvein the water after some time.Note: Coffee is used in this activity because making hot coffee is common tostudents and such will show how heating a liquid can affect how fast a soliddissolves.Let the students draw diagrams or illustrations showing the stages of asolid dissolving. Ask students questions like the following:• Does coffee dissolve faster in hot water?• What is the best way to make “cold coffee”?The Effect of TemperatureMost solids, like coffee powder, dissolve faster in hot water than incold water. At higher temperature, the water particles in move faster andcome in contact more frequently with the solute particles (the coffeepowder).Activity6Which Dissolves Faster in Hot and in Cold Water:Sugar or Salt?The nature of soluteQuestions to investigate: Does salt dissolve faster in hot water than incold water? Does sugar dissolve faster in hot water than in cold water?1. Ask students to investigate how temperature affects how fast sugar andsalt dissolve in water.Grade 7 Science: MatterDiversity of Materials in the Environment 10WHAT ARE THE PROPERTIES OF SOLUTIONS?