by: Nathalie Balbontin

Density

Description

In this lesson, students will explore the formula for density (Density = Mass / Volume) and how an object’s density determines whether it will sink or float.

Introduction

1. Make a density column by mixing different liquids (water, oil, syrup) and solids (a bolt, a grape, a bottle cap, etc.) in a tall clear container. Before adding each new substance, ask students to predict what will happen.
2. Ask students to propose reasons for why the substances arranged themselves the way they did (e.g., Why is the oil floating on top of the water?). Explain that the substances are layered according to their densities.

Working On It

1. Explain that density is a property of matter that can be described numerically and calculated. To calculate the density of a substance, we need two pieces of information: mass and volume. Introduce the equation: Density = Mass / Volume.
2. Have students explore the Density Simulation on Scratch. Provide them with guiding questions to focus their exploration (these can be given on a worksheet or written on the board). Suggested questions include:
   1. a. What happens if we increase the mass of the object?
   2. At what point does the object switch from floating to sinking?
   3. What can you infer about the density of water based on this simulation?

The provided code only allows students to adjust the mass of the object (i.e., the volume is fixed). Challenge students to use this as starter code and modify the program so they can vary both the mass and the volume. Ask them to explore what happens if they increase or decrease the volume while keeping the mass the same.

Consolidation

1. Bring the class back together for a group discussion. Invite students to share their answers to the guiding questions. Address any misconceptions or questions that arise.
2. Encourage students to think about real-life or practical situations where they have observed density in action and invite them to share those examples with the class.

Resource Information

Tags: Science; Fluids; Density; Variables; Algebra

Main Subject: Science (Expectation C2.2 demonstrate an understanding of the relationship between mass, volume, and density)

Other integrated subjects: Math (algebra and coding)

Learning to code: Yes

Coding to learn: Yes

URL link to code: https://scratch.mit.edu/projects/1143042989