Grade: Middle
Subject: Science

Teachers.Net Lesson Plans

#108. Chemical Reaction in a Bag

Science, level: Middle
Posted by Michael H. Edmondson (
Hardaway High School, USA
Materials Required: Zip loc bag, baking soda, phenol red, vinegar, calcium chloride
Activity Time: 1 class period
Concepts Taught: Chemical reactions, gases, indicators


Purpose: Students will learn to make careful observations involving chemical reactions.

Materials Needed:

Road salt (calcium chloride)
Baking soda (sodium hydrogen carbonate)
Indicator (phenol red or bromthymol blue work well)
Baggies, sandwich size (regular and ziplock)
Spatulas or plastic spoons
10 ml graduated cylinders


1. Put two scoops of road salt and one scoop of baking soda into a ziplock bag.

2. In another baggie (not ziplock) put 10 ml of indicator.

3. Place the baggie containing indicator inside the ziplock bag with salt and soda. Be sure the indicator baggie is completely stuffed into the ziplock bag.

4. Carefully squeeze all air out of the ziplock bag.

5. Zip the top of the ziplock bag.

6. Invert the bag so that all contents of both bags combine. Make observations.


Several evidences of a chemical reaction are very apparent (color change, gas produced, heat produced., etc.)

Make a list of all the observations you can gather. These include mass changes (if any), color changes, temperature of materials, sounds, and any other change you may note. Make this list on your own paper.