EXPERIMENT Light and Dark Visitors experiment with several objects that glow in the dark through fluorescence, some that glow through phosphorescence, and some that do not glow in the dark at all. They place the objects in a lightproof box and observe them through a viewing area at the top of the box. Visitors can also switch on a black light inside the box. OBJECTIVES: Visitors learn how some objects glow in the dark. They learn the difference between fluorescence and phosphorescence. SCIENCE TOPICS PROCESS SKILLS VOCABULARY Light Observing Atom Phosphorescence Classifying Electron Fluorescence Investigating Energy Properties of Electrons Comparing/Contrasting Properties of Molecules Predicting Unit 6 The Chemistry of Toys U6.19 Experiencing Chemistry ©1997 OMSI Experiment: Light and Dark Operating Guide (with amounts to have on hand) ¼-in. plywood: four pieces, each 11 in. by 11 in.; one piece, 11 in. by 11.5 in.; two pieces, each 4 in. by 4 in.; plus two pieces, each 4 in. by 6 in. Heavyweight, opaque black fabric 1½ ft. by 1½ ft. (drapery fabric works well) White vinyl mat or material made of flexible, waterproof material 24 screws, longer than the plywood thickness One staple gun Black paper (four sheets) One ceramic lightbulb socket with attached cord (to mount in box) One push-button momentary switch Insulated electrical wire (about 6 in.) One “black light” bulb (keep two on hand) Thirty 6-in. glow-in-the-dark sticks (available from Dear Creek products, Inc., (305) 978-0597) One toy car painted fluorescent yellow One glow-in-the-dark toy One yellow toy (not fluorescent or glow-in-the-dark) . One small box or tray to hold toys Three boxes for glow sticks (longer than 6 in.) One spray bottle for cleaning solution Cleaning solution (for example, Formula 409) Box of tissues One large plastic beaker Setup/Takedown Procedures Label the large plastic beaker “Waste Tissues.” Set up the view box (see photograph): Build an 11-in. cube from the plywood with the following adaptations: Leave the front open, to be covered by a heavy black curtain. Cut a 6 in. by 3 in. viewing hole in the top. Attach a “head rest” over the viewing hole. The head rest is made as a 4 in. by 6 in. rectangular box with no top or bottom. The two 6-in. edges have an arc cut out along the top edge to allow a curved forehead to rest on them. U6.22 Unit 6 The Chemistry of Toys Experiencing Chemistry ©1997 OMSI Experiment: Light and Dark Operating Guide Line the inside of the box with black paper. In the upper left-hand corner of the back piece inside the box, attach a light socket. Install a momentary switch (button that turns light on only while it is held down) on the exterior of the box so that visitors can push it. Locate the switch in the upper back corner of the left- hand side. Connect the switch to the light socket. Screw the “black light” bulb into the socket. Set up the glow stick dispensing box and the used glow stick box (see photograph): Punch a hole in one end of each box large enough for a glow stick to fit through. Label the hole in one box “Glow Sticks,” “Dispense Here.” Label the hole in the other box “Insert Used Glow Sticks Here.” Using a rubber band, secure the lids of the boxes to discourage visitors from opening the boxes. Label the third box “Extra Glow Sticks.” Collect the view box from storage. Set out the view box and plug it in; test to see that the light works. At least 15 min before opening, quickly remove the glow sticks from the used glow stick box. Fill the dispensing box ½ full with glow sticks. Store extra sticks in the “Extra Glow Sticks” box. Refill the spray cleaner and tissue if necessary. Set out the dispensing and used glow stick boxes. Set out the spray cleaner and tissues. Set out the box or tray with the toy car, glow-in-the-dark toy, and yellow toy. Transfer the used glow sticks to the glow stick dispensing box. Store extra glow sticks in the “Extra Glow Sticks” box. Unit 6 The Chemistry of Toys U6.23 Experiencing Chemistry ©1997 OMSI Experiment: Light and Dark Operating Guide Return all equipment except the view box to the experiment tub. Clean the view box, especially the viewing area. Return the view box to the storeroom. ◊ Check the glow stick dispensing box periodically and replenish it as needed. Transfer new sticks from the “Used Glow Sticks” box or “Extra Glow Sticks” box. Transfer quickly and in a fairly dark area. Glow sticks will regenerate within ten minutes or less if not exposed to light very long. ◊ Periodically check the inside of the view box for stray toys and glow sticks. Experiments could be done on the glow sticks to chart exposure time vs. glow time. Various toys and objects could be viewed under black light to test for fluorescence. No special precautions are needed; follow standard lab safety procedures. U6.24 Unit 6 The Chemistry of Toys Experiencing Chemistry ©1997 OMSI .