Driving Question: How Can I Smell Things From Across the Room?

This is a 6-week, project-based unit designed for 6th grade students. In order to contextualize chemistry concepts and scientific inquiry in real-world student experiences, the unit focuses on how people can smell odors from a distance. Central to this unit is students’ development of a model of the particulate nature of matter, which includes the following features: Air and all other gases are substances; substances are made of particles; in the gaseous state, there is empty space between the particles (the particles are not attached to each other); the particles are moving constantly.

There are three learning sets in the instructional sequence.

Learning Set 1 focuses on the behavior of gases in order to help students begin to understand the particulate nature of all matter. Students construct models, which are revisited throughout the unit, to explain how odors move in the air. Modeling is a scientific practice central to this unit, as students construct models, study the purposes of models, revise models based on new information, and examine the limitations of models in science.

Learning Set 2 introduces elements, atoms and then molecules. Students learn that the arrangement of atoms (in different molecules) determines the odor of a substance. This learning set also emphasizes the differences among substances: their properties.

In Learning Set 3, students use the particulate model to represent the three states of matter, to explain what happens at melting and boiling points, to explain phase changes, and to explain the relationship between temperature and the movement of molecules in each state (solid, liquid, gas).