Pure Substances & Mixtures (Grade 7)

Use Jamboard or Padlet and create a Venn diagram. Students compare and contrast pure substances, solutions, and mechanical mixtures.

Students work in a group to do an oil spill simulation. Each group will follow the steps below and complete an observation sheet:

1. In a paper cup, mix 4 spoons of vegetable oil with 1-4 drops of red food colouring (note that they will not mix). The vegetable oil represents crude oil and the food colouring represents chemicals trapped inside the oil.
2. Fill the container with water, then pour the oil and food colouring mixture – this represents oil spill. Float a popsicle stick, which represents a ship, in the middle of the oil spill. Answer Question 1 in the observation sheet.
3. Use cotton balls, cardboard, and paper towels (smaller than 1 inch), and foam/sponge and try to remove the oil before it reaches the sides of their container.
4. Record the findings in the observation sheet (under “BEFORE the Use of Dispersant”).
5. Add a few drops of dishwashing soap: dispersant. Answer Question 2 in the observation sheet.
6. Repeat Step 3, then record the findings in the observation sheet (under “AFTER the Use of Dispersant”).