Small Groups
Activities involving dry ice and root beer help students understand the chemical and physical changes that occur in matter.
Additional Resources
Books
The Root Beer Book: A Celebration of America's Best-Loved Soft Drink, by Laura E. Quarantiello; ISBN 0936653787
A Flying Needs Lots of Root Beer, by Charles M. Schulz; ISBN 0694010464
Root Beer Lady: The Dorothy Molter Story, by Bob Cary; ISBN 0938586688
A physical change involves the changes that can be observed without changing the identity of substances. A chemical change is a process in which reactants are changed into one or more different products. A chemical change occurs whenever compounds are formed or decomposed. During this reaction, there is a rearrangement of atoms that makes or breaks chemical bonds. This change is usually not reversible.
Another way in which the distinction between chemical and physical changes is often expressed is to state that only chemical reactions involve the rearrangement of atoms within the molecule, which leads to the creation of a new molecule (new substance). Physical change does not create anything new; there is no change in the identity of the material (substance).
Changes in state but not chemical composition are not considered chemical changes. For example, while boiling water involves a change in temperature and the release of a gas (water vapor), a chemical change did not take place.
1. Use science process and thinking skills.
Invitation to Learn
Which Soda Pop Contains the Most Fizz?
In this activity the class will be split up into five or six different groups. Each group will be given a different brand 24 oz. bottle of soda pop. The groups will predict which soda has the most fizz and tell why they think that. The groups will be instructed to equally disperse about 1⁄2 of their bottle to the members of their group using small cups. As the students drink their soda, instruct them to think about descriptive words to describe how the soda pop tastes. The students will write these words on 3x5 cards. The groups will then take the remainder of their soda in the bottle and put a balloon over the opening. Have the students will take turns shaking the bottle lightly. The balloon will begin to fill with carbon dioxide. Then, have the groups will then take the carbon dioxide filled balloons and tie them off. The groups measure their balloons on the scale provided to see how much carbon dioxide was released from their soda. The groups will then compare their findings.
Instructional Procedures
A fun (and often wild) activity vividly demonstrates the sublimation process. Place a piece of dry ice into a plastic 35mm film container - the kind that has the snap-on cap. Then wait. The cap will pop off, and sometimes fly several meters. The clear Fuji brand containers shoot farther than the gray and black Kodak type. Warn anyone performing this experiment not to aim for anyone's eyes.
Press a warm spoon firmly against a chunk of dry ice. The spoon will scream loudly as the heat of the spoon causes the dry ice to instantly turn to gas where the two make contact. The pressure of this gas pushes the spoon away from the dry ice, and without contact, the dry ice stops sublimating. The spoon falls back into contact again, and the cycle repeats. This all happens so quickly that the spoon vibrates, causing the singing sound you hear.
When you place dry ice into some warm or hot water, clouds of white fog are created. This white fog is not the CO 2 gas, but rather it is condensed water vapor, mixed in with the invisible CO 2. The extreme cold causes the water vapor to condense into clouds. The fog is heavy, being carried by the CO 2, and will settle to the bottom of a container, and can be poured.
Curriculum Extensions/Adaptations/ Integration
Family Connections
Research Basis
Maryland State Dept. of Education, Baltimore Div. of Instruction (1988). Better Thinking and Learning: Building Effective Teaching through Educational Research. 1-98.
Instruction in 30 program areas, this paper is designed as a resource to assist teachers in expanding and refining teaching strategies. Topics included in the article include: activating prior knowledge, cooperative learning, critical thinking, graphic organizers, and metacognitive strategies.
Bathajthy, Ernest. (1988). From Metacognition to Whole Language: The Spectrum of Literacy in Elementary School Science. 26p.
This article considers the integration of reading and writing into elementary science. The article discusses the use of graphic organizers for teaching text structure, and the use of semantic feature analysis for teaching vocabulary concepts.