Chemical Interactions, Second Edition

Grades 6 - 8

Chemistry is an inquiry into the structure, properties, and composition of matter, as well as the energy dynamics that accompany matter transformations. Students conduct experiments to observe macroscopic matter transformations, such as phase change, dissolution, and reaction, and apply kinetic particle theory to explain those transformations at the microscopic level. In the process, students learn conventions for thinking and communicating about chemical concepts. They also observe energy transfers associated with reactions and infer energy transfers associated with phase change. A diverse mix of empirical experiences and theoretical models helps students construct a solid basic understanding of the composition of their world and the interactions that maintain and transform it.

Investigation 1:
In Substances students are introduced to substances as unique forms of matter.
Investigation 2:
In Elements students learn that elements are the fundamental substances from which all matter is made, and that the periodic table displays all of the known elements.
Investigation 3:
In Particles students are introduced to the particle theory of matter and use it to explain how gas can be compressed.
Investigation 4:
In Kinetic Energy students observe expansion and contraction of solids, liquids, and gas, and explain those observations in terms of the kinetic energy of particles.
Investigation 5:
In Energy Transfer students explain heating up and cooling down in terms of changes of kinetic energy resulting from collisions between particles.
Investigation 6:
In Thermos Energy students use their understanding of energy transfer to face an engineering problem: how to build a container that keeps hot liquids hot and cold liquids cold.
Investigation 7:
In Solutions Students explore the difference between melting and dissolving. They go on to study dissolving by comparing aqueous mixtures, one with a soluble solid and one with an insoluble solid.
Investigation 8:
In Phase Change students experience three common phases (states) of matter—solid, liquid, and gas— and investigate the conditions that induce substances to change from one phase to another.
Investigation 9:
In Reaction students observe that starting substances (reactants) change into new substances (products) during reactions, and explain the change in terms of the rearrangement of atoms.
Investigation 10:
In Limiting Factors students conduct more chemical reactions, learning about limiting factors and reactants in excess.