Lesson Plan: Mixtures and Pure Substances

Lesson plan developed and implemented by Amanda Sanniti and Melanie Sleep (Chantier7 Project Team Members)

Unit: Chemistry - Mixtures and Pure Substances

Pre-test:

Question: Observe the following images. Which image best illustrates a salt water solution at a molecular level?

 (Developed by The Chantier 7 project team members)

 

Instruction:

1. Teacher places one 4-corner “placemat” on every second table.
2. Assign students into groups of 4 and place them at a table with a placemat. (A-D).
3. Students pick up Chromebooks and open the Google Form “Mixtures and Pure Substances”.  Students do not answer yet.
4. Students read through the Google Form questions and write the answers they choose down on their section of the placemat, keeping their answers covered until all in their group have completed them.
5. Each group member shares their answers for the first question and their reasoning. (Call on each letter one question at a time) The group must come to a consensus (need not be unanimous) for question #1 before moving on to #2.  Do this for all 5 questions.
6. Once all questions have been discussed and a group consensus reached and written in the center, students return to their desks and answer the Form individually; their answers will be informed by the group discussion but may not be the same as the group consensus.
7. Distribute worksheets: “Mixtures and Pure Substances Handout”.

Demo #1: Marbles in Water

Show students that you have marbles and water and ask them to complete the particle models for each on the handout.  Add the marbles to a beaker of water.  Ask them for observations about the mixture after you have stirred.

Verbal discussion lead in:

• Do they see signs of a chemical change?
• If not, what is this telling you is happening at a particle level to the marbles and the water?
• Complete Demo #1 section on handout, drawing particle models for before and after the particles are mixed.

Demo #2:  Salt and Water

Show students that you are going to mix salt into a beaker of water.  Have students draw the particle models for salt and water separately.  Add the salt to a beaker of water.  Ask them for observations about this mixture after you have stirred.

Verbal discussion lead in:

• Do students see signs of a chemical change?
• If not, what is this telling you is happening at a particle level to the marbles and the water?
• Complete Demo #2 section on handout, drawing particle models for before and after the particles are mixed.

Demo #3:  Sulfur and Iron

Have students observe the sulfur and iron separately, drawing particle models for each and describing their color and texture.  Test both substances with a magnet.  Mix the iron and sulfur together until it appears homogeneous. 

Verbal discussion lead in: 

• Do students see signs of a chemical change?
• If not, what is this telling you about what is happening at a particle level to the iron and the sulfur?
• Complete Demo #3 section on handout, drawing particle models for before and after the particles are mixed.

Post-test

Question: Observe the following images. Circle the beaker that contains a mixture.

(Developed by The Chantier 7 project team members)