Blizzard in a Bottle

Modified from Flinn Scientific & D. Chapleau

Background: In this lab, you will learn about how some solutes that are only partly soluble can be forced to fully dissolve with heat. This lab has a serendipitous beginning when a supersaturated solution of benzoic acid was forgotten on a lab bench and allowed to cool! Voila! “A blizzard in a bottle”!

Objective: SWBAT explore the variables associated with making solutions in order to make a snow globe.

Safety: Although benzoic acid serves as a food preservative, it will irritate both eyes and skin if contact occurs. Do not play with the chemical solution. Leave the jar closed. Wear goggles and aprons at all times. Wear gloves when handling benzoic acid. Wash hands thoroughly before leaving the laboratory. Procedure: 1. Calculations: This procedure is for one baby food sized jar. Modify the quantities as necessary for your jar and group.

 1 small baby food jar = 75 mL H2O & ~ 1 gram of benzoic acid.

 1 large jar = 150 mL H2O & ~ 2 grams of benzoic acid.

# small jars: ______# large jars: ______Quantity of water needed for group: ______Quantity of benzoic acid needed for group: ______2. Get your calculations checked by the teacher. Teacher’s Initials: ______

3. Heat about 75 ml (______) of tap water in a beaker, but do not allow it to boil! 4. While the water is heating, measure between 0.9 and 1.1 grams of benzoic acid (______). Keep the cap on the benzoic acid when it is not in use to eliminate odors.

5. Place the benzoic acid into the heated water. With the beaker on the hot plate, stir the mixture until the benzoic acid completely dissolves and makes a solution. Remove the solution from the hot plate and allow it to begin cooling.

6. Take your figure and your VERY DRY AND CLEAN jar over to the hot glue station. Use a pair of forceps to hold the figure by its head with your most coordinated hand. Use your other hand to put some hot glue on the bottom of the figure, then immediately place the figure on the bottom of the jar. Hold it for a few seconds so it stays in place. Allow the glue to cool for several minutes.

7. Watch your benzoic acid solution as it begins to cool, and you will see beautiful snowy looking crystals appear. Allow the solution to completely cool to room temperature (if you don't, the figure usually falls off).

8. After your solution is cool, and the figure has been glued, stir the snow mixture a few times, then quickly pour it into the jar, on top of your holiday figure. You will not fill the jar with this procedure.

9. Slowly add water to fill the jar to the brim (use the graduated cylinder, don't try doing it directly from the faucet). Try to leave as little air as possible in the jar. Air pockets tend to cause the benzoic acid to clump at the top.

10. Place your cap on tightly. If all is well, you should be able to turn the snow scene upside down and watch your figure get buried in the blizzard!!

11. Something you can try when you get home is to use some silicon adhesive around the edge of the jar lid to seal it completely. DO NOT RE-OPEN THE SNOW GLOBE. BE CAREFUL NOT TO DRINK FROM THAT CUP OR TO GET ANY OF THE SOLUTION IN YOUR EYES!

Analysis:

Write a paragraph explaining the chemical phenomenon that was exploited to make snow globes today. Your paragraph must use the following twelve words/terms in the appropriate context: solute solvent solution supersaturated saturated heat cool solubility dissolve benzoic acid snow precipitate

You can use hot instead of heat, soluble instead of solubility, etc. You must underline, highlight, or bold each term. You can type and print your paragraph. This makes editing easier. Name(s) and signature(s) must accompany each paragraph that is turned in.