Interactive, scaffolded model
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In this activity, students determine what holds ions in solution, and they experiment with dissolving different solutes in various solvents.
Students will be able to:
The Dissolving model-based activity is designed to help students learn what is happening at the atomic level when a substance dissolves. Students see that particles of the substance, such as ions or polar molecules, are attracted to water molecules more strongly than they are attracted to each other. It is these intermolecular attractions that are responsible for the process of dissolving.
In this activity students will consider what happens when different types of substance are added to water:
For this activity to be most successful, students should have some idea about the different types of bonds (Stepping Stone 2) as well as understand that the strong polar nature of water molecule allows it to be one of the most universal solvents.
Polar water attracts polar molecules and ions, and pushes out non-polar and non-charged substances.
Additional Related Concepts
There are several models in the database that help students learn about water. If your students have not acquired this information, you may want to have students do these models first:
The model Water: Getting to Know the Water Molecule -- Activity #140 (http://molo.concord.org/database/activities/140.html) has students look at the properties of water and how these properties influence intermolecular interactions.
This dissolving activity was originally field tested as part of a unit on solutions and solubility, Aquatic Solutions and Our Cells