Lesson plan

Mixtures with a focus on colloids

Summary
Mix materials to discover different kinds of mixtures, then focus on colloids.
Science content
Chemistry: Atoms, Molecules (3-7)
Chemistry: Physical Changes, Solutions, Mixtures and Separating (2, 4, 5, 6)
Materials
  • materials in the activities
  • optional: transmission microscope, slides and coverslips, pipette to look closely at the particles in colloids
Procedure

Discover and define differnet kinds of mixtures with the Making Mixtures activity.

Optional: Look at the colloidal particles in milk under the microscope (see photo), by making a slide of a milk drop. Under 100X power you can see the fat droplets, and at 400X power you can see that they are variously-sized. They are all small enough to stay in the milk, and not settle to the bottom.

Then make colloids, butter is recommended as there are three colloids in its making (cream, whipped cream and butter).
Alternatively, make oobleck or flubber, which are also colloids.

Optional: Set up a transmission microscope for small student groups to visit. Make a slide of whole milk to see the fat particles of varying sizes at high power. Make a slide of oobleck to see the cornstarch particles, with a different appearance from the milk.

See attached files for summary of mixtures including colloids.

Attached documents
Grades taught
Gr 4
Gr 5
Gr 6