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Lesson Plan

Dyes

Summary: 
Make red cabbage dye and vary it's colour with acid/base. Use to dye fabric. Separate the dyes in felt pens.
Science content (2016 curriculum): 
Chemistry: States of Matter, Properties of Materials (K-7)
Chemistry: Physical Changes, Solutions, Mixtures and Separating (2, 4, 5, 6)
Chemistry: Chemical Changes (2, 7)
Procedure: 

Make red cabbage dye and experiment with how it changes colour in acid or base.
Use to dye cotton strips/cotton yarn, and use them for weaving.
Discuss how many plant colours vary with acid and base.

Discuss how dyes are colours dissolved in water to make a solution. (A pigment, often used in paints, is a suspension of a solid in a liquid.) See notes.

Separate the dyes in felt pens using chromatography.
Use the resulting patterns to make art work.

Notes: 

The colour in children's markers is a dye - a solution of coloured molecules in water. Permanent markers, dry erase pens and ballpoint pens are also dyes in a solvent. Paints are generally a pigment - a colloid of solid particles suspended in a liquid. Pigment-based art materials are more opaque than dye-based art materials.
Should be able to see the difference between a dye and a pigment under the microscope.

Grades taught: 
Gr 4
Teacher: 
Ingrid
Site tested: 
ingridscience afterschool
Lesson plan originally developed and delivered: 

ingridscience aferschool