In this unit, students will learn to describe the structure of solids, liquids and gases in terms of particle arrangements and energy present within the molecular structure. Experiments to show the arrangements of particles, how heating and cooling changes the arrangements and also diffusion and osmosis of molecules in our daily life.
Understand a model for how matter is constructed.
McREL: Science, McREL: Level III (Grades 6-8) , Physical Sciences
Standard 8. Understands the structure and properties of matter
- Knows that matter is made up of tiny particles called atoms, and different arrangements of atoms into groups compose all substances
- Knows that atoms often combine to form a molecule (or crystal), the smallest particle of a substance that retains its properties
- Knows that states of matter depend on molecular arrangement and motion (e.g., molecules in solids are packed tightly together and their movement is restricted to vibrations; molecules in liquids are loosely packed and move easily past each other; molecules in gases are quite far apart and move about freely)
- Knows that many elements can be grouped according to similar properties (e.g., highly reactive metals, less-reactive metals, highly reactive nonmetals, almost completely nonreactive gases)
- Understands the conservation of mass in physical and chemical change (e.g., no matter how substances within a closed system interact with one another, the total weight of the system remains the same; the same number of atoms of a single element weighs the same, no matter how the atoms are arranged)
- Knows methods used to separate mixtures into their component parts (boiling, filtering, chromatography, screening)
- Knows that substances react chemically in characteristic ways with other substances to form new substances (compounds) with different characteristic properties
- Knows factors that influence reaction rates (e.g., types of substances involved, temperature, concentration of reactant molecules, amount of contact between reactant molecules)