Performance Standards/ Disciplinary Core Ideas / Science & Engineering Practices:
Teacher asks, “How can I make these pennies shiny again?”
Students should brainstorm what kind of change this will be and what – discuss ideas.
Teacher tries to wash the pennies and shows the luster and color does not change.
Teacher shows various liquids— some weak acids, like vinegar (white vinegar apple cider vinegar, malt vinegar… ), lemon juice, orange juice., water, milk,…
Teacher tells students they will chooses a liquid (1/2 cup) and salt (2 tsp). Teacher should provide measurements (standard units — tell the students they have to determine the metric units).
Next teacher mixes the (liquid) and salt, and places pennies in this solution. (use words mixture, solution, dissolve) Take pennies out 5 minutes later and rinses and dry on paper towel.
Students should “imagine” and brainstorm claims/hypotheses. Use STEM Engineering Design Plan for rough draft, then this paper for final work.
Teacher asks, “I wonder what will happen with the steel bolts or nails and screws if I place them in the vinegar salt solution that the pennies were in?” Teacher places a bolt in the solution, with a nail half in/half out of solution and states that she will leave it for 10 minutes and then check back.