This activity provides an exciting and colorful chemical reaction that students can hold in their hands. It’s a great activity for the first couple of weeks of science class as it requires easy prep, any easy procedure to follow, and a fun and interesting phenomena for students to practice making good observations and asking questions about empirical evidence.
Each student will need goggles.
Each group of three students will need:
A small (50 mL) beaker with solid calcium chloride pellets (I use the kind made for putting in pools at Home Depot)
A small (50 mL) beaker with baking soda (sodium bicarbonate)
2 teaspoons (one in each beaker above)
Phenol red solution (0.02%) (available on Amazon or at science supply stores like Flinn Scientific)
A Ziploc sandwich bag (or generic brand!) that has a ‘ziplock’
A sharpie marker
(optionally) a tray to hold materials
Copies of pages 2-5 of this resource
Students should follow the procedure and record observations. They should also label what they see happening in the bag on the picture of the bag under the data table. Then, they should brainstorm a list of “What if…?” and “I wonder…?” questions about what they’ve observed. Maybe make a list of these on the board or have students use a polling app like Poll Everywhere to make a digital brainstorming wall on the front screen of your classroom. If you have enough materials, you may ask students to take this activity a step further and design controlled experiments to test some of their questions. They can make a data table in their science notebook and actually do the tests and collect data. Or, if you don’t have enough materials, test some of their ideas as a demonstration to continue the conversation about what combinations of chemicals produced the color change, heating up, cooling down, and gas!
Have the students complete the analysis questions after performing the lab. Use these to discuss the concepts of quantitative, qualitative, endothermic, exothermic, chemical equations, and indications of chemical reactions!
Thanks for looking!