Where's My Shine?

Learning Resource Type

Learning Activity

Subject Area

Science

Grade(s)

8

Overview

This learning activity should be used during a lesson on investigating chemical and physical changes.  The students will dissolve metal oxides formed on the surfaces of a penny into an ionic solution in order to investigate chemical and physical changes. This learning activity can be used as an assessment.

This activity was created as a result of the ALEX Resource Development Summit.

Phase

During/Explore/Explain
Science (2015) Grade(s): 8

SC15.8.5

Observe and analyze characteristic properties of substances (e.g., odor, density, solubility, flammability, melting point, boiling point) before and after the substances combine to determine if a chemical reaction has occurred.

UP:SC15.8.5

Vocabulary

  • Characteristic properties (e.g., odor, density, solubility, flammability, melting point, boiling point)
  • Substances
  • Chemical reaction

Knowledge

Students know:
  • Each pure substance has characteristic physical and chemical properties that can be used to identify it.
  • Characteristic properties of substances may include odor, density, solubility, flammability, melting point, and boiling point.
  • Chemical reactions change characteristic properties of substances.
  • Substances react chemically in characteristic ways.
  • In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants.

Skills

Students are able to:
  • Observe characteristic physical and chemical properties of pure substances before and after they interact.
  • Analyze characteristic physical and chemical properties of pure substances before and after they interact.
  • Analyze the properties to identify patterns (i.e., similarities and differences), including the changes in physical and chemical properties of each substance before and after the interaction.
  • Use the analysis to determine whether a chemical reaction has occurred.

Understanding

Students understand that:
  • Observations and analyses can be used to determine whether a chemical reaction has occurred.
  • The change in properties of substances is related to the rearrangement of atoms in the reactants and products in a chemical reaction (e.g., when a reaction has occurred, atoms from the substances present before the interaction must have been rearranged into new configurations, resulting in the properties of new substances).

Scientific and Engineering Practices

Analyzing and Interpreting Data

Crosscutting Concepts

Patterns

Learning Objectives

The students will be able to observe and analyze characteristic properties of ions in a compound, ions in a solution, and ions forming new ionic bonds before and after the substances combine to determine if a chemical reaction has occurred.

Activity Details

Lab Safety Rules should be reviewed before starting this Learning Activity.

  1. Distribute 2 beakers per group.
  2. Distribute goggles for each student.
  3. Pour 50 mL of distilled vinegar into each of the 250 mL beakers per group.
  4. In one beaker, use a teaspoon to add a spoonful of table salt to the distilled vinegar for each group. (Only add table salt to one of the beakers.)
  5. Students should use a plastic spoon to stir the vinegar and salt until the salt is dissolved completely.
  6. Add 5 "dirty" pennies to the vinegar-salt solution and add 5 "dirty" pennies to the plain distilled vinegar.
  7. Leave the pennies in each of the solutions for 10 minutes. (Students should set a timer.)
  8. Students should observe the pennies every 2 minutes.
  9. After 10 minutes, use one plastic spoon to remove the 5 pennies from the vinegar-salt solution and the other plastic spoon to remove the pennies from the vinegar.
  10. Rinse all pennies using water and dry them, but keep the 2 groups of pennies separated.
  11. Students will compare the "dirty' pennies to the pennies that have spent 10 minutes in the ionic solution (vinegar-salt solution) to the pennies in the vinegar solution using the Venn Diagram.

Assessment Strategies

Bring students back to the whole group and discuss the following (Questions are on the bottom of the Venn Diagram):

  1. What happened to the pennies to make them "dirty?"  Pennies become dull over time because the copper ions on the surface of the pennies react with oxygen in the air and form copper (II) oxide.
  2. What is an ionic solution? An ionic solution contains ions. For example, when table salt is dissolved in water.  
  3. What happened to the "dirty" pennies once they were placed in the ionic solution? When the "dirty" pennies were placed in the vinegar-salt solution, the copper ions separated from the oxygen ions. These ions dissolve in the solution.
  4. Based on what we observed during the experiment, did a chemical change occur? Why or why not? What evidence can you provide to explain your answer? A chemical did occur. You know a chemical change happened because the copper oxidizing is a chemical change and not a physical change (like simply getting dirt on something), soap will not wash it off. It takes a chemical reaction! The acetic acid in the vinegar reacts with the copper oxide and dissolves it.

Variation Tips

The size of the beakers may be adjusted as long as it will hold 50mL of distilled vinegar, a teaspoon of table salt, and 5 pennies. Also, lemon juice may be used instead of distilled vinegar. Lastly, in order to save copies, the Venn Diagram may be assigned through Google Classroom.

Background / Preparation

The teacher should gather the following materials to complete this learning activity:

  1. 250 mL Beaker (enough for each group to have 2)
  2. Teaspoon
  3. 2 Plastic Spoon
  4. 10 "dirty" pennies 
  5. Distilled Vinegar (room temperature)
  6. Paper Towels
  7. Timer
  8. Goggles
  9. Table Salt
  10. Print the Venn Diagram

 

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