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Activity

Making mixtures to discover physical and chemical changes

Summary: 
Experiment freely with mixing a variety of solids and liquids, and find that each mixture has different properties. Discussion on physical changes, chemical changes, kinds of mixtures and chemical reactions.
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)
Materials: 
  • ice cube tray (not white), or little pots to mix in e.g. dollar store shot glasses
  • coffee stirrer sticks
  • a variety of solids in separate cups e.g. flour, sugar, salt, rice, sand, baking soda
  • a variety of liquids in separate squeeze bottles e.g. water, vinegar
Procedure: 

This activity has been run using the Play-Debrief-Replay model of science education described in "The New Teaching Elementary Science" book (see resource).

Students try mixing different combinations of solids and liquids and record what they find.
At some point, if necessary, encourage pair wise mixing so that they can determine which substances produce the result seen.
Students write down their discoveries, so that they can refer to them when the group is brought together to discuss findings.

Some expected outcomes and terminology with the materials listed:
Absorb: some solids will soak up liquids
Dissolving: some solids will “disappear” into the liquid as they dissolve in it. Solute/solvent.
Suspension: some solids will disperse in a liquid but not dissolve, to make a suspension.
Solutions and suspensions are both kinds of mixtures.
Chemical reaction: some solids and liquids will react together to make new things (gas bubbles appear when baking soda and vinegar are mixed).

Notes: 

This is a general exploration of mixtures and chemical reactions. For a more focused exploration of mixtures (suspensions, solutions and colloids) see Making Mixtures.

Kindergarteners at Tyee were given baking soda, vinegar, water and sugar. They were asked to find a chemical change (when it looks different).
baking soda, vinegar, flour, water, sugar

Grades taught: 
Gr K
Gr 1
Gr 2
Gr 3
Teacher: 
Barbara Duncan
Becky Evermon
Ingrid
Patricia Ellis
Wendy Zwaagstra
Teaching site: 
Laurier Elementary
Selkirk Elementary
Tyee Elementary
Activity originally developed and delivered: 

Scientist in Residence Program, Vancouver.