Solutions

Summary

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 material solutions.

Science content

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)

Activities in this lesson

Epsom salt crystal painting

Chromatography with coloured marker pens

Chromatography with black markers and forensics of ink on a note

Red cabbage dye (and pH indicator)

Growing sugar crystals

Procedure

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, to show formation of a solution, then separation of components by crystallization.

The chromatography activity shows another method of separating components of a solution. This method is used a lot by chemists and forensic scientists, and was used to discover the structure of insulin.
Optional extension: forensic chromatography with black pens.

To explore the concept of concentration, use red cabbage dye to measure the pH in various household materials. Also introduction to acids and bases.

The sugar crystal activity makes edible crystals, but note that the crystals will not be ready for a few days.

Grades taught

Gr 3

Gr 4

Gr 5

Gr 6

Lesson plan