Minds on Science Gazette

Volume 9

Planning Activities: Physical Science

Designing Units & Courses

In this activity students will investigate a chemical reaction occurring in a plastic baggie.

Objectives

• Observe a chemical reaction
• Describe the evidence indicating a chemical reaction has taken place

Concepts

• Chemical
• Chemical change
• Heat
• Gas
• Indicator

Materials

Calcium chloride, sodium bicarbonate (baking soda), red cabbage juice (boil red cabbage for 5 minutes, pour off liquid), or phenol red indicator, zip lock plastic bags (quart size), plastic spoon

Procedure

1, Ask students what they think is a chemical. Write their answers on the board.

2. Ask students what they think might happen if two chemicals are mixed together. Write their responses on the board.

3. Explain to the students that they are going to explore chemicals and chemical reactions using relatively safe chemicals, but they should keep chemical off their cloths and skin, rinsing with water if chemical do make contact, wiping up spills as they happen, and washing hands at the end of the activity.

4. Have teams of students obtain small cups containing baking soda and calcium chloride, small bottle of cabbage juice, wood splints, vial, goggles, and 1 plastic ziplock bag.

5. Give students a handout that contains the instructions and questions for investigation.

Inquiry Procedure

1. Measure one spoonful of calcium chloride and place it into the ziplock bag.

2. Add one spoonful of sodium bicarbonate (baking soda) to the bag. Zip the bag closed and shake it to observe for any evidence of a chemical change.

3. Pour 10 mL of cabbage juice into a small vial. Carefully put the vial into the baggie without spilling the indicator.

4. Zip the bag closed.

5. Tip the vial of indicator.

Inquiry Questions

1. What happened when the indicator mixed with the baking soda and calcium chloride?

2. What are at least five observations?

3. Do you think a chemical reaction occurred?

4. How would you define a chemical reaction?

1. What safety precautions will you take doing this activity? Can safety precautions be included as intended learning outcomes? How would you phrase a learning outcome that addressed safety in the science classroom?

2. Draw a concept map using the concepts listed above. Be sure to include the linking phrases.

3. What are some additional activities that you could do with these chemicals that would build on this initial activity? List ideas for at least three-to-five lessons.