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Lesson Plan


Make crystals and understand the chemistry of dissolving and crystallization, as water is added to then removed from a solution. Separate the components of a solution through chromatography of marker pen ink. Use red cabbage dye to measure the pH of household materials.
Science content (2016 curriculum): 
Chemistry: States of Matter, Properties of Materials (K-7)
Chemistry: Atoms, Molecules (3-7)
Chemistry: Physical Changes, Solutions, Mixtures and Separating (2, 4, 5, 6)
Curriculum connection (2005 science topic): 
Physical Science: Chemistry (grade 7)

Introduce what a solution is - a mixture where the particles are evenly distributed and completely mixed up.
Do a selection of the activities to show how solutions can be made and separated (crystal making, and chromatography), and how concentration of solutions can be measured (red cabbage dye as a pH indicator).

Do the Epsom salt crystal activity, starting with showing students how the crystals dissolve in water.
Once students see the crystals, summarize again what is happening: the molecules of the epsom salts organize themselves in a regular arrangement to make crystals. Called crystallization.

Start the sugar crystal activity. Note that the crystals will not be ready for a few days.

The chromatography activity also separates out mixtures of molecules. This method is used a lot by chemists and forensic scientists, and was used to discover the structure of insulin.
Do the Chromatography with marker pens activity. Explain what is happening in terms of molecules while students work.

Introduce the idea of concentration. Students use red cabbage dye to measure the pH (or concentration of hydrogen atoms) in various household materials. Discuss how this relates to how acidic or basic materials are.


Laurier did epsom salt paintings, sugar crystals, then chromatography.
Maple Grove did Epsom salts, chromatography and red cabbage - too many activities for an hour and a half lesson. Stick with two of these if students are engaged and would experiment a bit with the chromatography or red cabbage.

Grades tested: 
Gr 3
Gr 4
Gr 5
Gr 6
Gretchen Bartlett
Sonia Ko
Sonja Watson
Site tested: 
Maple Grove Elementary
Laurier Elementary
Lesson plan originally developed and delivered: 

Laurier Elementary with the Vancouver School Board's Scientist in Residence Program