During this CELL, students will conduct several investigations focused on calculating the density of matter. By conducting experiments, investigating different variables, and utilizing formulas, students will begin to draw conclusions concerning the relationship between the mass and volume of an object and the density of that object.
Students will explore the density of matter in a number of different ways in this CELL. They will begin their exploration of density by comparing how liquids with different densities will interact with one another, and how liquids interact with solids. Through measurements of mass and volume, and use of the mathematical formula, density = mass ÷ volume, students will determine the density of five solid objects, the density of water, and the density of two additional liquids. Students will also conduct an investigation that examines how the density of water changes as solute is added. In the Performance Assessment, students will have an opportunity to apply their knowledge from this CELL, by selecting the appropriate materials needed to construct and test a defined model of an undersea city. By the conclusion of this CELL, students should realize that density is a property of all matter and that it is a constant value that is dependent on mass and volume. As the mass and volume of a solid or a liquid increases, the density of the solid or liquid will also increase. Students should also discover that the density of water will increase as more solute is added.
Through performing experiments and participating in class discussions, students will begin to comprehend that all matter found in the world around them has density. This CELL will promote students’ awareness of matter and density that they encounter in their daily lives, building continuity between classroom investigations and daily applications.
___________________________________________________________________
Investigation 1: Introducing Density
Investigation One introduces students to the concept of density. Through observation and experimentation, students will learn that different liquids and different solids have different densities. Students will use volumetric equipment to combine two different liquids and to combine liquids and solids. Their observations will enable them to realize that matter that has a low density will float above matter that has a higher density.
Investigation 1: Teacher’s Video (11:42)
Investigation 1: Student’s Video (13:24)
___________________________________________________________________
Investigation 2: Calculating the Density of Water
In Investigation Two, students will calculate the density of water. Students will use volumetric equipment and a triple beam balance to obtain measurements of different volumes of water. Students will then use a mathematical formula to calculate the density of water. Students will discover that the density of water is a constant value of 1 g/ml. Their measurements and calculations will enable them to realize that if the mass and volume of water is changed, the density of water will not change.
Investigation 2: Teacher’s Video (4:17)
Investigation 2: Student’s Video (7:42)
___________________________________________________________________
Investigation 3: Densities of Different Liquids
During Investigation Three, students will compare the densities of three different liquids. Students will use volumetric equipment and a triple beam balance to obtain measurements of different volumes of each liquid. Students will then calculate the density of each liquid using a mathematical formula. Through their experiments, students will conclude that different liquids have different constant values. They will also come to realize that when the mass or volume of any liquid is changed, the density of that liquid will not change.
Investigation 3: Teacher’s Video (8:59)
Investigation 3: Student’s Video (12:00)
___________________________________________________________________
Investigation 4: Densities of Different Solids
Investigation Four gives students an opportunity to explore the density of five different solid objects. Through measurement and calculations, students will calculate the density of each solid. Students will discover that the volume of each solid can be measured by use of a mathematical formula or by the volume displacement method. Their observations will enable them to realize that solid matter has a constant density that is dependent upon the mass and volume of the solid, but that different solids have different densities.
Investigation 4: Teacher’s Video (8:28)
Investigation 4: Student’s Video (19:10)
___________________________________________________________________