Physical and Chemical Changes

Name of Activity

Physical and Chemical Changes

Author

Tom DePalma, Yash Gurditta, Dan Weinstein

Keywords

chemistry, baking soda, vinegar, fun, experiment, space, mars, gas, ballon, propulsion

Subject

Miscellaneous

Grade Level

3, 4, 5, 6

Time

1 Hour

Brief Description

The activity is structured like a traditional classroom experiment and is used to teach the difference between physical and chemical reactions.

Learning Goals:

Introduce students to basic principles of chemistry–Teach students how to analyze and interpret observations and use data to solve problems

Materials:

water, vinegar, baking soda, corn starch, table salt, plastic cups, large plastic bins, paper towels, newspaper

Preparation:

Prepare samples of each substance for groups. Could prepare a table if you want but we found letting the kids design their own worked much better

Knowledge Background

Notes: The activity is somewhat messy so it s a good idea to notify the teacher in advance.  The kids have a hard time understanding the difference between the two types of reactions.  Discussion after the experiment and before the challenge task it definitely the most important part of the activity.

Background:

Vinegar and baking soda react to produce a gas

Alka seltzer and water/vinegar react to for gas

corn starch and water/vinegar form a goopy solution

table salt and water/vinegar–>dissolves

Procedure

To start the class, we discussed the difference between physical and chemical changes. The group provided examples of both and we wrote them on the board. Using the list, we were able to create a spirit list of characteristics to be used in determining if an event results in a physical or chemical change.

The activity is structured like a traditional classroom experiment. The students were split into groups of three and were given these materials: Baking soda, table salt, alka seltzer, corn starch, water and vinegar. Their task was to mix each of the sold substances with the two liquids and record their observations. Each group was told to design a table to record their observations.

Each table was covered in newspaper to keep the areas clean and the experiments were performed in plastic NXT bins. Each group was given a pre-allocated amount of each substance and told that was all they would be receiving.

The reactions and the observations took about 20 minutes. After completing this, the group came together and the results were discussed.

The next part of the activity can be done by each group individually if time allows. We ran out of time so it was done as a class demonstration. The class observed that some of the reactions lead to the production of gas. We gave the class the challenge of blowing up the balloon using one of the reactions. They chose what materials would be best and we put the solid in the ballon and the liquid in a plastic water bottle. The balloon was stretched over the neck of the bottle and the solid was dumped into the liquid. The balloon inflated.

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