Density - An Introduction

This lesson is an introduction to density.  Students will explore a variety of materials and learn how density, mass, and volume are related. They will be introduced to how density in liquids affects their behavior. They will learn how to calculate the density of a cube using a scale and a ruler. In addition, they will hear the tale of Archimedes and learn how to use a graduated cylinder to solve for volume via the displacement of water. This lesson also reviews math skills, requiring students to multiply and divide to solve problems. (Most appropriate for grades 5-9, easily adjusted to fit each grade level.)

Lesson Time: 60 minutes

This lesson can be shortened if necessary. To fit a 45 min class period Activity 3 or 4 can be omitted. Activity 4 is more appropriate for higher grade levels.

Adult Demonstration 1:  Students will act out the concept of density using a square defined on the floor with masking tape. As more students step into the square the area becomes more dense!

Adult Demonstration 2: The students are amazed by a density bottle (filled with beads and liquid).

Student Activity 1: Students explore density and buoyancy using density spheres and a cup of water.

Student Activity 2: Our wizard will teach the students how to solve for the density of a rectangle and a cube.

Student Activity 3: Students will work in groups to determine the density of a series of density cubes.

Student Activity 4: Students will learn about Archimedes and how to solve for volume by displacement.

Adult Demonstration 3: Density of liquids is observed and discussed. Now that the students have a better grasp of the concepts the phenomena of the density bottle from demonstration 1 is further explored.

Group work: Students should work in groups of 3-4 students (materials provided for 7 groups total)

Use decimal notation for fractions with denominators 10 or 100. For example, rewrite 0.62 as 62/100; describe a length as 0.62 meters; locate 0.62 on a number line diagram.
 4.NF.7 Compare two decimals to hundredths by reasoning about their size. Recognize that comparisons are valid only when the two decimals refer to the same whole.
5.NF.3 Interpret a fraction as division of the numerator by the denominator (a/b = a ÷ b).
5.MD.3: 3 Recognize volume as an attribute of solid figures and understand concepts of volume measurement. a. A cube with side length 1 unit, called a “unit cube,” is said to have “one cubic unit” of volume, and can be used to measure volume. b. A solid figure which can be packed without gaps or overlaps using n unit cubes is said to have a volume of n cubic units.
5.MD.5: Relate volume to the operations of multiplication and addition and solve real-world and mathematical problems involving volume. a. Find the volume of a right rectangular prism with whole number side lengths by packing it with unit cubes, and show that the volume is the same as would be found by multiplying the edge lengths, equivalently by multiplying the height by the area of the base. Represent threefold whole number products as volumes, e.g., to represent the Associative Property of Multiplication. b. Apply the formulas V = ℓ × w × h
6.PS.1:  Matter is made up of small particles called atoms. Matter has mass, volume, and density and is made up of small particles called atoms. Single kinds of atoms are elements, combinations of two or more atoms joined chemically are called molecules.
PS.M.1: Classification of matter: Heterogeneous vs. homogeneous (alloys are discussed, liquid solutions and the separation of heterogeneous mixtures).  Properties of matter (density).