Snow Globe Chemistry
In this Chemistry activity, students create a snow globe using the concept of "like dissolves like." Students will be provided with several liquid solvents and solid solutes. Students will predict and test the best mixture to create an aesthetically pleasing snow globe. In order to complete this activity, students should have prior knowledge of polarity, solutions, and solubility. Students report their findings in a science lab format.
-Students will write a standard lab report showing data collection and reporting their results.
-Students will use and develop cooperative learning skills.
-Students will review and apply the concept of polarity and "like dissolves like."
-Students will apply what they learned about polarity to create a mixture in which the solute will not dissolve in the solvent.
-Students will promote Chemistry by showing and explaining to others "What they made in class today."
Key Terms: solutions, solubility, polarity, solute, solvent, mixture.
Context for Use
It is advisable that students come to class with the written lab report partially completed from "title" through "data table." The lab work takes about 40-50 minutes.
Description and Teaching Materials
1 baby food jar per group, hot glue gun, small item to place in globe (brought in by student), rubbing alcohol, 4 small vials (or test tubes), water, vegetable oil, baby oil, sodium chloride, Epsom salt, sucrose, cornstarch, sand, sodium bicarbonate, laundry detergent.
Students choose 4 different combinations of solute and solvent. In their lab notebook, students create a data table showing each combination, their prediction for each combination (before mixing), and the scientific reasoning for their predictions. For example, if the combination is water and sodium chloride, the combination will dissolve because water is polar and sodium chloride is ionic. Like dissolves like (both have charged parts). In contrast, vegetable oil will not dissolve the salt because the oil is nonpolar and the salt is ionic. Students also include a rating of each combination (after mixing).
To minimize waste, each solution is tested in a small vial (or test tube) and then the best combination is put into the baby food jar. To prepare the jar, clean the jar, the lid of the jar and the item with rubbing alcohol. Let the alcohol evaporate. Affix the item to the cap of the baby food jar with hot glue. Fill the jar with the selected solute and solvent. Apply a ring of hot glue around the inside of the lid. While the lid is still hot, screw the lid on the jar.
This activity was developed by Ian Gutch and Tom Haugh
Teaching Notes and Tips
Part of the goal is to create a globe that is aesthetically pleasing. There are many combinations that are insoluble however, not every one of those mixtures is desirable. Some cause the mixture to be cloudy or milky. The best combinations are vegetable oil/Epsom salt, or baby oil/Epsom salt.
This lab could be modified by supplying the solvents and then having students find and bring in their own solutes. The danger here is that they may not have ANY appropriate solute and therefore do not have any combination that will make a good snow globe.
This is a messy lab. Watch for spills along the way. Allow 5-7 minutes for clean up.
The lab could be followed by a discussion of biodegradable products or the polarity of different types of packing peanuts.
Physical Science 126.96.36.199.1 - 188.8.131.52.4: Matter
Chemistry 9C.184.108.40.206: Solutions
Chemistry 9C.220.127.116.11: Solubility