Solve the Mystery Lab and Make a Silver Christmas Ornament
By Susan Godfrey
Carolina Teaching Partner
Traditional Christmas: the family singing carols while cutting down the perfectly shaped tree on grandma and grandpa’s farm, stringing popcorn and cranberries for garland, fashioning angels from macaroni. Modern Christmas: grandma got run over by a reindeer, grandpa is in Florida soaking up some rays. The pre-lit Christmas tree is from the big-box discount center, and the color-coordinated ornaments are from a “designer” line carried at a favored department store.
However, you can still practice one tradition—fashioning ornaments—but through the not-so-traditional use of a chemistry mystery. Don’t let the Christmas season come and go without creating memorabilia to pass along to future generations of chemistry prodigies. This lab helps your students make the pretty keepsake ornament for their parents and learn some chemistry, too!
Bring curling ribbon and ornament hangers to school for students’ use in embellishing their creations. Use any size rimmed test tube. Recommended size is 10 × 75 mm with rim. You also need a glass stirrer, cork stoppers large enough to fit slightly into the top of the test tube, labels, and markers. With the 4 “mystery” solutions and a little Christmas-oriented chemistry, your students will create silver mirrors inside test tubes that make beautiful ornaments. Prepare the solutions needed for students to use in the silver ornament lab.
- 2.5 g Glucose (or dextrose)
- 2.5 g Levulose
- 350 mL Distilled Water
- 0.6 g Tartaric Acid
- 10 mL Ethyl Alcohol
- 4.0 g Silver Nitrate
- 6.0 g Ammonium Nitrate
- 10 g Sodium Hydroxide
- 3 Glass Beakers
- Dropping Pipet
- Heat Source
- Solution W: Dissolve 2.5 g of glucose (or dextrose) and 2.5 g levulose in 50 mL distilled water. Add 0.6 g tartaric acid and heat the solution to a boil. Allow to cool; add 10 mL ethyl alcohol as a stabilizer. Dilute to 100 mL with distilled water.
- Solution X: Dissolve 4.0 g silver nitrate in 50 mL distilled water.
- Solution Y: Dissolve 6.0 g ammonium nitrate in 50 mL distilled water.
- Solution Z: Dissolve 10 g sodium hydroxide in 100 mL distilled water.
- For the waste beaker, pour 100 mL of water into a 250 mL beaker and add at least 40 g of sodium chloride. Stir until no more sodium chloride will dissolve. The solution will be saturated and should contain undissolved sodium chloride. Note: Warning! Explosive silver fulminate (Ag2C2N2O2) may form if unreacted waste mixture is allowed to stand without being added to the sodium chloride solution. Adding the waste mixtures to sodium chloride solution creates silver chloride, which is stable.
Silver ornament lab
Purpose: To use a chemical reaction to create a silver mirror on the inside of a test tube
- 2 Small Test Tubes (with rim and marking label)
- 1 Cork Stopper (large enough to fit slightly into the top of the test tube)
- “Mystery” Solutions W, X, Y, and Z
- Distilled Water
- Read all MSDS labels for chemical hazards.
- Wear chemical-resistant apron, gloves, and goggles.
- Dispose of waste according to local, state, and federal regulations.
- Place 10 drops of Solution W in a new, dry test tube.
- In a separate test tube, put 5 drops of Solution X and 5 drops of Solution Y. Stopper the test tube, shake to mix, then pour into test tube with Solution W.
- In a separate test tube, put 5 drops of Solution X and 5 drops of Solution Y.
- Quickly add 10 drops of Solution Z; stopper and shake the test tube. Continue rotating the test tube on its side, keeping all surfaces wet, for about 1 minute, or until you see a uniform coating inside the test tube.
- Immediately pour residue into the waste beaker. Rinse the test tube thoroughly with water.
- Dry the outside and shake water out of the test tube. Do not rub the inside of the tube.
- Tie a piece of ribbon and hanger around the tube; put the cork stopper in the tube if desired.
- Put the date on the test tube marking label and give it to your mom (or special whoever) for Christmas. She will love it!
What type of reaction could have caused silver deposits inside the test tube?
Chemical reaction and conclusion
A redox (shorthand for oxidation-reduction) reaction occurs in which the silver ion from Solution X is reduced by the reducing sugars, glucose and levulose, from Solution W. The aldehyde part of the sugar molecule is oxidized. Commercial companies use this process to resilver mirrors. Now that you’ve solved this mystery lab, maybe you can work on solving how Santa gets his jolly self in and down, and up and out of that chimney. Merry Christmas!