Palo Alto Unified School District — Science OnLine Guide
for Teachers
Mixtures and Solutions
5th Grade Physical Science Unit |
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General Information
The Mixtures and Solutions unit is a Full Option Science System (FOSS)
kit created by the
Lawrence Hall of Science at the University of California, Berkeley. It is published by Britannica.
In this unit students are expected to
- Gain experience with the concepts of mixture and solution
- Gain experience with the concepts of concentration and saturation
- Gain experience with the concept of chemical reaction
- Apply an operational definition to determine the relative concentrations of solutions
- Use group problem-solving techniques to plan investigations
- Use measurement in the context of scientific investigations
- Apply mathematics in the context of science
- Acquire some vocabulary associated with chemistry
- Gain experiences that will contribute to their understanding of several pervasive themes that point out connections among scientific ideas and processes: Pattern, Structure, Interaction, and Change.
Core Concepts
Matter occupies space and has substance with observable properties.
- Mixtures are a combination of two or more materials which retain their individual properties and can be separated by physical means.
- A solution is a special kind of mixture which cannot be separated by filtration but may be separated by evaporation or some other physical means.
- A saturated solution is one in which no more of the solid material can be dissolved.
- Solubility is the property that substances have of dissolving in solvents. Solubility is different for different materials and can change with temperature and different solvents.
- A solution is saturated when as much solid material as possible has dissolved in the liquid.
- Concentration expresses a relationship between the amount of dissolved materials and the volumn of solvent.
- When a change occurs as a result of mixing two or more materials, that change is a chemical reaction. A reaction results in new materials.
Misconceptions
- Some students have difficulty believing that water is a solvent thinking instead that only "chemicals" can be solvents.
- For some students atomic theory may be too abstract. This unit can be considered an introduction because the information will be studied again in more depth at the eighth grade level.
