Task:

At this station, you will observe two types of interactions, and then be asked to answer some questions about the interactions.

Materials: 2 resealable plastic bags 2 twist ties 1 half teaspoon measure 1 - 50 mL graduated cylinder baking soda vinegar water paper towels safety goggles

Background:

Directions:

Part A

1. In one of the bags, put 1/2 teaspoon of baking soda into one corner.
2. Tie off the corner of the bag with a twist tie as shown in the diagram.
3. Measure 30mL of WATER and pour it into the empty corner.
4. Remove as much air as possible and seal the bag tightly.
5. Remove the twist tie from the bag and gently mix the baking soda with the water.
6. Describe what you observed after you mixed the contents of this bag. List 2 observations.

7. Set the bag aside, and continue with Part B.

Part B

Questions:

1. In which of the bags did a chemical change occur? Circle your answer.

2. Based on your knowledge of science and your observations, explain why you think a chemical change occurred. Give 2 reasons to support your answer.

3. Based on your knowledge of science and your observations, explain why you think a chemical change occurred. Give 2 reasons to support your answer.

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